Merge in from trunk r64802 - r68625

[wxWidgets.git] / src / png / pngrtran.c

diff --git a/src/png/pngrtran.c b/src/png/pngrtran.c
index 489554c7e43060458e105bf0c81107fcf6f27f07..b5e8f1a26f2b1386d287359dd1a19e82abc4fde5 100644 (file)
--- a/src/png/pngrtran.c
+++ b/src/png/pngrtran.c
@@ -1,11 +1,14 @@
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *

- * libpng 1.0.3 - January 14, 1999
- * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
- * Copyright (c) 1996, 1997 Andreas Dilger
- * Copyright (c) 1998, 1999 Glenn Randers-Pehrson
+ * Last changed in libpng 1.4.2 [May 6, 2010]
+ * Copyright (c) 1998-2010 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h

  *
  * This file contains functions optionally called by an application
  * in order to tell libpng how to handle data when reading a PNG.
  *
  * This file contains functions optionally called by an application
  * in order to tell libpng how to handle data when reading a PNG.


@@ -13,64 +16,72 @@
  * in pngtrans.c.
  */
 
  * in pngtrans.c.
  */
 

-#define PNG_INTERNAL
+#define PNG_NO_PEDANTIC_WARNINGS

 #include "png.h"
 #include "png.h"

-
-#if defined(_MSC_VER) && !defined(__MWERKS__)
-#define __VISUALC__ _MSC_VER
-#endif
-#ifdef __VISUALC__
-#ifndef WIN32
-#pragma warning(disable:4135)
-#endif
-#endif
+#ifdef PNG_READ_SUPPORTED
+#include "pngpriv.h"

 
 /* Set the action on getting a CRC error for an ancillary or critical chunk. */
 
 /* Set the action on getting a CRC error for an ancillary or critical chunk. */

-void
+void PNGAPI

 png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
 {
 png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
 {

-   png_debug(1, "in png_set_crc_action\n");
+   png_debug(1, "in png_set_crc_action");
+ 
+   if (png_ptr == NULL)
+      return;
+

    /* Tell libpng how we react to CRC errors in critical chunks */
    switch (crit_action)
    {
    /* Tell libpng how we react to CRC errors in critical chunks */
    switch (crit_action)
    {

-      case PNG_CRC_NO_CHANGE:                        /* leave setting as is */
+      case PNG_CRC_NO_CHANGE:                        /* Leave setting as is */

          break;
          break;

-      case PNG_CRC_WARN_USE:                               /* warn/use data */
+
+      case PNG_CRC_WARN_USE:                               /* Warn/use data */

          png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
          break;
          png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
          break;

-      case PNG_CRC_QUIET_USE:                             /* quiet/use data */
+
+      case PNG_CRC_QUIET_USE:                             /* Quiet/use data */

          png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
                            PNG_FLAG_CRC_CRITICAL_IGNORE;
          break;
          png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
                            PNG_FLAG_CRC_CRITICAL_IGNORE;
          break;

-      case PNG_CRC_WARN_DISCARD:    /* not a valid action for critical data */
-         png_warning(png_ptr, "Can't discard critical data on CRC error.");
-      case PNG_CRC_ERROR_QUIT:                                /* error/quit */
+
+      case PNG_CRC_WARN_DISCARD:    /* Not a valid action for critical data */
+         png_warning(png_ptr,
+            "Can't discard critical data on CRC error");
+      case PNG_CRC_ERROR_QUIT:                                /* Error/quit */
+

       case PNG_CRC_DEFAULT:
       default:
          png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
          break;
    }
 
       case PNG_CRC_DEFAULT:
       default:
          png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
          break;
    }
 

+   /* Tell libpng how we react to CRC errors in ancillary chunks */

    switch (ancil_action)
    {
    switch (ancil_action)
    {

-      case PNG_CRC_NO_CHANGE:                       /* leave setting as is */
+      case PNG_CRC_NO_CHANGE:                       /* Leave setting as is */

          break;
          break;

-      case PNG_CRC_WARN_USE:                              /* warn/use data */
+
+      case PNG_CRC_WARN_USE:                              /* Warn/use data */

          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
          break;
          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
          break;

-      case PNG_CRC_QUIET_USE:                            /* quiet/use data */
+
+      case PNG_CRC_QUIET_USE:                            /* Quiet/use data */

          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
                            PNG_FLAG_CRC_ANCILLARY_NOWARN;
          break;
          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
                            PNG_FLAG_CRC_ANCILLARY_NOWARN;
          break;

-      case PNG_CRC_ERROR_QUIT:                               /* error/quit */
+
+      case PNG_CRC_ERROR_QUIT:                               /* Error/quit */

          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
          break;
          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
          png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
          break;

-      case PNG_CRC_WARN_DISCARD:                      /* warn/discard data */
+
+      case PNG_CRC_WARN_DISCARD:                      /* Warn/discard data */
+

       case PNG_CRC_DEFAULT:
       default:
          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
       case PNG_CRC_DEFAULT:
       default:
          png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;


@@ -78,14 +89,18 @@ png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
    }
 }
 
    }
 }
 

-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
-/* handle alpha and tRNS via a background color */
-void
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+    defined(PNG_FLOATING_POINT_SUPPORTED)
+/* Handle alpha and tRNS via a background color */
+void PNGAPI

 png_set_background(png_structp png_ptr,
    png_color_16p background_color, int background_gamma_code,
    int need_expand, double background_gamma)
 {
 png_set_background(png_structp png_ptr,
    png_color_16p background_color, int background_gamma_code,
    int need_expand, double background_gamma)
 {

-   png_debug(1, "in png_set_background\n");
+   png_debug(1, "in png_set_background");
+ 
+   if (png_ptr == NULL)
+      return;

    if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
    {
       png_warning(png_ptr, "Application must supply a known background gamma");
    if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
    {
       png_warning(png_ptr, "Application must supply a known background gamma");


@@ -93,50 +108,46 @@ png_set_background(png_structp png_ptr,
    }
 
    png_ptr->transformations |= PNG_BACKGROUND;
    }
 
    png_ptr->transformations |= PNG_BACKGROUND;

-   png_memcpy(&(png_ptr->background), background_color, sizeof(png_color_16));
+   png_memcpy(&(png_ptr->background), background_color,
+      png_sizeof(png_color_16));

    png_ptr->background_gamma = (float)background_gamma;
    png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
    png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0);
    png_ptr->background_gamma = (float)background_gamma;
    png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
    png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0);

-
-   /* Note:  if need_expand is set and color_type is either RGB or RGB_ALPHA
-    * (in which case need_expand is superfluous anyway), the background color
-    * might actually be gray yet not be flagged as such. This is not a problem
-    * for the current code, which uses PNG_FLAG_BACKGROUND_IS_GRAY only to
-    * decide when to do the png_do_gray_to_rgb() transformation.
-    */
-   if ((need_expand && !(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) ||
-       (!need_expand && background_color->red == background_color->green &&
-        background_color->red == background_color->blue))
-      png_ptr->flags |= PNG_FLAG_BACKGROUND_IS_GRAY;

 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_16_TO_8_SUPPORTED)
-/* strip 16 bit depth files to 8 bit depth */
-void
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+/* Strip 16 bit depth files to 8 bit depth */
+void PNGAPI

 png_set_strip_16(png_structp png_ptr)
 {
 png_set_strip_16(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_strip_16\n");
+   png_debug(1, "in png_set_strip_16");
+
+   if (png_ptr == NULL)
+      return;

    png_ptr->transformations |= PNG_16_TO_8;
 }
 #endif
 
    png_ptr->transformations |= PNG_16_TO_8;
 }
 #endif
 

-#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
-void
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+void PNGAPI

 png_set_strip_alpha(png_structp png_ptr)
 {
 png_set_strip_alpha(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_strip_alpha\n");
-   png_ptr->transformations |= PNG_STRIP_ALPHA;
+   png_debug(1, "in png_set_strip_alpha");
+
+   if (png_ptr == NULL)
+      return;
+   png_ptr->flags |= PNG_FLAG_STRIP_ALPHA;

 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_DITHER_SUPPORTED)
-/* Dither file to 8 bit.  Supply a palette, the current number
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+/* Quantize file to 8 bit.  Supply a palette, the current number

  * of elements in the palette, the maximum number of elements
  * allowed, and a histogram if possible.  If the current number
  * of colors is greater then the maximum number, the palette will be
  * of elements in the palette, the maximum number of elements
  * allowed, and a histogram if possible.  If the current number
  * of colors is greater then the maximum number, the palette will be

- * modified to fit in the maximum number.  "full_dither" indicates
- * whether we need a dithering cube set up for RGB images, or if we
+ * modified to fit in the maximum number.  "full_quantize" indicates
+ * whether we need a quantizeing cube set up for RGB images, or if we

  * simply are reducing the number of colors in a paletted image.
  */
 
  * simply are reducing the number of colors in a paletted image.
  */
 


@@ -149,22 +160,25 @@ typedef struct png_dsort_struct
 typedef png_dsort FAR *       png_dsortp;
 typedef png_dsort FAR * FAR * png_dsortpp;
 
 typedef png_dsort FAR *       png_dsortp;
 typedef png_dsort FAR * FAR * png_dsortpp;
 

-void
-png_set_dither(png_structp png_ptr, png_colorp palette,
+void PNGAPI
+png_set_quantize(png_structp png_ptr, png_colorp palette,

    int num_palette, int maximum_colors, png_uint_16p histogram,
    int num_palette, int maximum_colors, png_uint_16p histogram,

-   int full_dither)
+   int full_quantize)

 {
 {

-   png_debug(1, "in png_set_dither\n");
-   png_ptr->transformations |= PNG_DITHER;
+   png_debug(1, "in png_set_quantize");
+
+   if (png_ptr == NULL)
+      return;
+   png_ptr->transformations |= PNG_QUANTIZE;

 
 

-   if (!full_dither)
+   if (!full_quantize)

    {
       int i;
 
    {
       int i;
 

-      png_ptr->dither_index = (png_bytep)png_malloc(png_ptr,
-         (png_uint_32)(num_palette * sizeof (png_byte)));
+      png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr,
+         (png_uint_32)(num_palette * png_sizeof(png_byte)));

       for (i = 0; i < num_palette; i++)
       for (i = 0; i < num_palette; i++)

-         png_ptr->dither_index[i] = (png_byte)i;
+         png_ptr->quantize_index[i] = (png_byte)i;

    }
 
    if (num_palette > maximum_colors)
    }
 
    if (num_palette > maximum_colors)


@@ -172,40 +186,42 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
       if (histogram != NULL)
       {
          /* This is easy enough, just throw out the least used colors.
       if (histogram != NULL)
       {
          /* This is easy enough, just throw out the least used colors.

-            Perhaps not the best solution, but good enough. */
+          * Perhaps not the best solution, but good enough.
+          */

 
          int i;
 
          int i;

-         png_bytep sort;

 
 

-         /* initialize an array to sort colors */
-         sort = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_palette
-            * sizeof (png_byte)));
+         /* Initialize an array to sort colors */
+         png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr,
+            (png_uint_32)(num_palette * png_sizeof(png_byte)));

 
 

-         /* initialize the sort array */
+         /* Initialize the quantize_sort array */

          for (i = 0; i < num_palette; i++)
          for (i = 0; i < num_palette; i++)

-            sort[i] = (png_byte)i;
+            png_ptr->quantize_sort[i] = (png_byte)i;

 
          /* Find the least used palette entries by starting a
 
          /* Find the least used palette entries by starting a

-            bubble sort, and running it until we have sorted
-            out enough colors.  Note that we don't care about
-            sorting all the colors, just finding which are
-            least used. */
+          * bubble sort, and running it until we have sorted
+          * out enough colors.  Note that we don't care about
+          * sorting all the colors, just finding which are
+          * least used.
+          */

 
          for (i = num_palette - 1; i >= maximum_colors; i--)
          {
 
          for (i = num_palette - 1; i >= maximum_colors; i--)
          {

-            int done; /* to stop early if the list is pre-sorted */
+            int done; /* To stop early if the list is pre-sorted */

             int j;
 
             done = 1;
             for (j = 0; j < i; j++)
             {
             int j;
 
             done = 1;
             for (j = 0; j < i; j++)
             {

-               if (histogram[sort[j]] < histogram[sort[j + 1]])
+               if (histogram[png_ptr->quantize_sort[j]]
+                   < histogram[png_ptr->quantize_sort[j + 1]])

                {
                   png_byte t;
 
                {
                   png_byte t;
 

-                  t = sort[j];
-                  sort[j] = sort[j + 1];
-                  sort[j + 1] = t;
+                  t = png_ptr->quantize_sort[j];
+                  png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1];
+                  png_ptr->quantize_sort[j + 1] = t;

                   done = 0;
                }
             }
                   done = 0;
                }
             }


@@ -213,20 +229,21 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
                break;
          }
 
                break;
          }
 

-         /* swap the palette around, and set up a table, if necessary */
-         if (full_dither)
+         /* Swap the palette around, and set up a table, if necessary */
+         if (full_quantize)

          {
             int j = num_palette;
 
          {
             int j = num_palette;
 

-            /* put all the useful colors within the max, but don't
-               move the others */
+            /* Put all the useful colors within the max, but don't
+             * move the others.
+             */

             for (i = 0; i < maximum_colors; i++)
             {
             for (i = 0; i < maximum_colors; i++)
             {

-               if ((int)sort[i] >= maximum_colors)
+               if ((int)png_ptr->quantize_sort[i] >= maximum_colors)

                {
                   do
                      j--;
                {
                   do
                      j--;

-                  while ((int)sort[j] >= maximum_colors);
+                  while ((int)png_ptr->quantize_sort[j] >= maximum_colors);

                   palette[i] = palette[j];
                }
             }
                   palette[i] = palette[j];
                }
             }


@@ -235,37 +252,38 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
          {
             int j = num_palette;
 
          {
             int j = num_palette;
 

-            /* move all the used colors inside the max limit, and
-               develop a translation table */
+            /* Move all the used colors inside the max limit, and
+             * develop a translation table.
+             */

             for (i = 0; i < maximum_colors; i++)
             {
             for (i = 0; i < maximum_colors; i++)
             {

-               /* only move the colors we need to */
-               if ((int)sort[i] >= maximum_colors)
+               /* Only move the colors we need to */
+               if ((int)png_ptr->quantize_sort[i] >= maximum_colors)

                {
                   png_color tmp_color;
 
                   do
                      j--;
                {
                   png_color tmp_color;
 
                   do
                      j--;

-                  while ((int)sort[j] >= maximum_colors);
+                  while ((int)png_ptr->quantize_sort[j] >= maximum_colors);

 
                   tmp_color = palette[j];
                   palette[j] = palette[i];
                   palette[i] = tmp_color;
 
                   tmp_color = palette[j];
                   palette[j] = palette[i];
                   palette[i] = tmp_color;

-                  /* indicate where the color went */
-                  png_ptr->dither_index[j] = (png_byte)i;
-                  png_ptr->dither_index[i] = (png_byte)j;
+                  /* Indicate where the color went */
+                  png_ptr->quantize_index[j] = (png_byte)i;
+                  png_ptr->quantize_index[i] = (png_byte)j;

                }
             }
 
                }
             }
 

-            /* find closest color for those colors we are not using */
+            /* Find closest color for those colors we are not using */

             for (i = 0; i < num_palette; i++)
             {
             for (i = 0; i < num_palette; i++)
             {

-               if ((int)png_ptr->dither_index[i] >= maximum_colors)
+               if ((int)png_ptr->quantize_index[i] >= maximum_colors)

                {
                   int min_d, k, min_k, d_index;
 
                {
                   int min_d, k, min_k, d_index;
 

-                  /* find the closest color to one we threw out */
-                  d_index = png_ptr->dither_index[i];
+                  /* Find the closest color to one we threw out */
+                  d_index = png_ptr->quantize_index[i];

                   min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
                   for (k = 1, min_k = 0; k < maximum_colors; k++)
                   {
                   min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
                   for (k = 1, min_k = 0; k < maximum_colors; k++)
                   {


@@ -279,61 +297,58 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
                         min_k = k;
                      }
                   }
                         min_k = k;
                      }
                   }

-                  /* point to closest color */
-                  png_ptr->dither_index[i] = (png_byte)min_k;
+                  /* Point to closest color */
+                  png_ptr->quantize_index[i] = (png_byte)min_k;

                }
             }
          }
                }
             }
          }

-         png_free(png_ptr, sort);
+         png_free(png_ptr, png_ptr->quantize_sort);
+         png_ptr->quantize_sort = NULL;

       }
       else
       {
          /* This is much harder to do simply (and quickly).  Perhaps
       }
       else
       {
          /* This is much harder to do simply (and quickly).  Perhaps

-            we need to go through a median cut routine, but those
-            don't always behave themselves with only a few colors
-            as input.  So we will just find the closest two colors,
-            and throw out one of them (chosen somewhat randomly).
-            [We don't understand this at all, so if someone wants to
-             work on improving it, be our guest - AED, GRP]
-            */
+          * we need to go through a median cut routine, but those
+          * don't always behave themselves with only a few colors
+          * as input.  So we will just find the closest two colors,
+          * and throw out one of them (chosen somewhat randomly).
+          * [We don't understand this at all, so if someone wants to
+          *  work on improving it, be our guest - AED, GRP]
+          */

          int i;
          int max_d;
          int num_new_palette;
          int i;
          int max_d;
          int num_new_palette;

+         png_dsortp t;

          png_dsortpp hash;
          png_dsortpp hash;

-         png_bytep index_to_palette;
-            /* where the original index currently is in the palette */
-         png_bytep palette_to_index;
-            /* which original index points to this palette color */
-
-         /* initialize palette index arrays */
-         index_to_palette = (png_bytep)png_malloc(png_ptr,
-            (png_uint_32)(num_palette * sizeof (png_byte)));
-         palette_to_index = (png_bytep)png_malloc(png_ptr,
-            (png_uint_32)(num_palette * sizeof (png_byte)));
-
-         /* initialize the sort array */
+
+         t = NULL;
+
+         /* Initialize palette index arrays */
+         png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
+            (png_uint_32)(num_palette * png_sizeof(png_byte)));
+         png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
+            (png_uint_32)(num_palette * png_sizeof(png_byte)));
+
+         /* Initialize the sort array */

          for (i = 0; i < num_palette; i++)
          {
          for (i = 0; i < num_palette; i++)
          {

-            index_to_palette[i] = (png_byte)i;
-            palette_to_index[i] = (png_byte)i;
+            png_ptr->index_to_palette[i] = (png_byte)i;
+            png_ptr->palette_to_index[i] = (png_byte)i;

          }
 
          }
 

-         hash = (png_dsortpp)png_malloc(png_ptr, (png_uint_32)(769 *
-            sizeof (png_dsortp)));
-         for (i = 0; i < 769; i++)
-            hash[i] = NULL;
-/*         png_memset(hash, 0, 769 * sizeof (png_dsortp)); */
+         hash = (png_dsortpp)png_calloc(png_ptr, (png_uint_32)(769 *
+            png_sizeof(png_dsortp)));

 
          num_new_palette = num_palette;
 
 
          num_new_palette = num_palette;
 

-         /* initial wild guess at how far apart the farthest pixel
-            pair we will be eliminating will be.  Larger
-            numbers mean more areas will be allocated, Smaller
-            numbers run the risk of not saving enough data, and
-            having to do this all over again.
-
-            I have not done extensive checking on this number.
-            */
+         /* Initial wild guess at how far apart the farthest pixel
+          * pair we will be eliminating will be.  Larger
+          * numbers mean more areas will be allocated, Smaller
+          * numbers run the risk of not saving enough data, and
+          * having to do this all over again.
+          *
+          * I have not done extensive checking on this number.
+          */

          max_d = 96;
 
          while (num_new_palette > maximum_colors)
          max_d = 96;
 
          while (num_new_palette > maximum_colors)


@@ -350,18 +365,22 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
 
                   if (d <= max_d)
                   {
 
                   if (d <= max_d)
                   {

-                     png_dsortp t;

 
 

-                     t = (png_dsortp)png_malloc(png_ptr, (png_uint_32)(sizeof
-                         (png_dsort)));
+                     t = (png_dsortp)png_malloc_warn(png_ptr,
+                         (png_uint_32)(png_sizeof(png_dsort)));
+                     if (t == NULL)
+                         break;

                      t->next = hash[d];
                      t->left = (png_byte)i;
                      t->right = (png_byte)j;
                      hash[d] = t;
                   }
                }
                      t->next = hash[d];
                      t->left = (png_byte)i;
                      t->right = (png_byte)j;
                      hash[d] = t;
                   }
                }

+               if (t == NULL)
+                  break;

             }
 
             }
 

+            if (t != NULL)

             for (i = 0; i <= max_d; i++)
             {
                if (hash[i] != NULL)
             for (i = 0; i <= max_d; i++)
             {
                if (hash[i] != NULL)


@@ -370,12 +389,14 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
 
                   for (p = hash[i]; p; p = p->next)
                   {
 
                   for (p = hash[i]; p; p = p->next)
                   {

-                     if ((int)index_to_palette[p->left] < num_new_palette &&
-                        (int)index_to_palette[p->right] < num_new_palette)
+                     if ((int)png_ptr->index_to_palette[p->left]
+                        < num_new_palette &&
+                        (int)png_ptr->index_to_palette[p->right]
+                        < num_new_palette)

                      {
                         int j, next_j;
 
                      {
                         int j, next_j;
 

-                        if (num_new_palette & 1)
+                        if (num_new_palette & 0x01)

                         {
                            j = p->left;
                            next_j = p->right;
                         {
                            j = p->left;
                            next_j = p->right;


@@ -387,31 +408,34 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
                         }
 
                         num_new_palette--;
                         }
 
                         num_new_palette--;

-                        palette[index_to_palette[j]] = palette[num_new_palette];
-                        if (!full_dither)
+                        palette[png_ptr->index_to_palette[j]]
+                          = palette[num_new_palette];
+                        if (!full_quantize)

                         {
                            int k;
 
                            for (k = 0; k < num_palette; k++)
                            {
                         {
                            int k;
 
                            for (k = 0; k < num_palette; k++)
                            {

-                              if (png_ptr->dither_index[k] ==
-                                 index_to_palette[j])
-                                 png_ptr->dither_index[k] =
-                                    index_to_palette[next_j];
-                              if ((int)png_ptr->dither_index[k] ==
+                              if (png_ptr->quantize_index[k] ==
+                                 png_ptr->index_to_palette[j])
+                                 png_ptr->quantize_index[k] =
+                                    png_ptr->index_to_palette[next_j];
+                              if ((int)png_ptr->quantize_index[k] ==

                                  num_new_palette)
                                  num_new_palette)

-                                 png_ptr->dither_index[k] =
-                                    index_to_palette[j];
+                                 png_ptr->quantize_index[k] =
+                                    png_ptr->index_to_palette[j];

                            }
                         }
 
                            }
                         }
 

-                        index_to_palette[palette_to_index[num_new_palette]] =
-                           index_to_palette[j];
-                        palette_to_index[index_to_palette[j]] =
-                           palette_to_index[num_new_palette];
+                        png_ptr->index_to_palette[png_ptr->palette_to_index
+                           [num_new_palette]] = png_ptr->index_to_palette[j];
+                        png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
+                           = png_ptr->palette_to_index[num_new_palette];

 
 

-                        index_to_palette[j] = (png_byte)num_new_palette;
-                        palette_to_index[num_new_palette] = (png_byte)j;
+                        png_ptr->index_to_palette[j] =
+                            (png_byte)num_new_palette;
+                        png_ptr->palette_to_index[num_new_palette] =
+                            (png_byte)j;

                      }
                      if (num_new_palette <= maximum_colors)
                         break;
                      }
                      if (num_new_palette <= maximum_colors)
                         break;


@@ -428,8 +452,6 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
                   png_dsortp p = hash[i];
                   while (p)
                   {
                   png_dsortp p = hash[i];
                   while (p)
                   {

-                     png_dsortp t;
-

                      t = p->next;
                      png_free(png_ptr, p);
                      p = t;
                      t = p->next;
                      png_free(png_ptr, p);
                      p = t;


@@ -440,8 +462,10 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
             max_d += 96;
          }
          png_free(png_ptr, hash);
             max_d += 96;
          }
          png_free(png_ptr, hash);

-         png_free(png_ptr, palette_to_index);
-         png_free(png_ptr, index_to_palette);
+         png_free(png_ptr, png_ptr->palette_to_index);
+         png_free(png_ptr, png_ptr->index_to_palette);
+         png_ptr->palette_to_index = NULL;
+         png_ptr->index_to_palette = NULL;

       }
       num_palette = maximum_colors;
    }
       }
       num_palette = maximum_colors;
    }


@@ -451,50 +475,51 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
    }
    png_ptr->num_palette = (png_uint_16)num_palette;
 
    }
    png_ptr->num_palette = (png_uint_16)num_palette;
 

-   if (full_dither)
+   if (full_quantize)

    {
       int i;
       png_bytep distance;
    {
       int i;
       png_bytep distance;

-      int total_bits = PNG_DITHER_RED_BITS + PNG_DITHER_GREEN_BITS +
-         PNG_DITHER_BLUE_BITS;
-      int num_red = (1 << PNG_DITHER_RED_BITS);
-      int num_green = (1 << PNG_DITHER_GREEN_BITS);
-      int num_blue = (1 << PNG_DITHER_BLUE_BITS);
+      int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS +
+         PNG_QUANTIZE_BLUE_BITS;
+      int num_red = (1 << PNG_QUANTIZE_RED_BITS);
+      int num_green = (1 << PNG_QUANTIZE_GREEN_BITS);
+      int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS);

       png_size_t num_entries = ((png_size_t)1 << total_bits);
 
       png_size_t num_entries = ((png_size_t)1 << total_bits);
 

-      png_ptr->palette_lookup = (png_bytep )png_malloc(png_ptr,
-         (png_uint_32)(num_entries * sizeof (png_byte)));
-
-      png_memset(png_ptr->palette_lookup, 0, num_entries * sizeof (png_byte));
+      png_ptr->palette_lookup = (png_bytep )png_calloc(png_ptr,
+         (png_uint_32)(num_entries * png_sizeof(png_byte)));

 
       distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries *
 
       distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries *

-         sizeof(png_byte)));
-
-      png_memset(distance, 0xff, num_entries * sizeof(png_byte));
+         png_sizeof(png_byte)));
+      png_memset(distance, 0xff, num_entries * png_sizeof(png_byte));

 
       for (i = 0; i < num_palette; i++)
       {
          int ir, ig, ib;
 
       for (i = 0; i < num_palette; i++)
       {
          int ir, ig, ib;

-         int r = (palette[i].red >> (8 - PNG_DITHER_RED_BITS));
-         int g = (palette[i].green >> (8 - PNG_DITHER_GREEN_BITS));
-         int b = (palette[i].blue >> (8 - PNG_DITHER_BLUE_BITS));
+         int r = (palette[i].red >> (8 - PNG_QUANTIZE_RED_BITS));
+         int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS));
+         int b = (palette[i].blue >> (8 - PNG_QUANTIZE_BLUE_BITS));

 
          for (ir = 0; ir < num_red; ir++)
          {
 
          for (ir = 0; ir < num_red; ir++)
          {

-            int dr = abs(ir - r);
-            int index_r = (ir << (PNG_DITHER_BLUE_BITS + PNG_DITHER_GREEN_BITS));
+            /* int dr = abs(ir - r); */
+            int dr = ((ir > r) ? ir - r : r - ir);
+            int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS +
+                PNG_QUANTIZE_GREEN_BITS));

 
             for (ig = 0; ig < num_green; ig++)
             {
 
             for (ig = 0; ig < num_green; ig++)
             {

-               int dg = abs(ig - g);
+               /* int dg = abs(ig - g); */
+               int dg = ((ig > g) ? ig - g : g - ig);

                int dt = dr + dg;
                int dm = ((dr > dg) ? dr : dg);
                int dt = dr + dg;
                int dm = ((dr > dg) ? dr : dg);

-               int index_g = index_r | (ig << PNG_DITHER_BLUE_BITS);
+               int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS);

 
                for (ib = 0; ib < num_blue; ib++)
                {
                   int d_index = index_g | ib;
 
                for (ib = 0; ib < num_blue; ib++)
                {
                   int d_index = index_g | ib;

-                  int db = abs(ib - b);
+                  /* int db = abs(ib - b); */
+                  int db = ((ib > b) ? ib - b : b - ib);

                   int dmax = ((dm > db) ? dm : db);
                   int d = dmax + dt + db;
 
                   int dmax = ((dm > db) ? dm : db);
                   int d = dmax + dt + db;
 


@@ -511,148 +536,303 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
       png_free(png_ptr, distance);
    }
 }
       png_free(png_ptr, distance);
    }
 }

-#endif
+#endif /* PNG_READ_QUANTIZE_SUPPORTED */

 
 

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)

 /* Transform the image from the file_gamma to the screen_gamma.  We
  * only do transformations on images where the file_gamma and screen_gamma
  * are not close reciprocals, otherwise it slows things down slightly, and
  * also needlessly introduces small errors.
 /* Transform the image from the file_gamma to the screen_gamma.  We
  * only do transformations on images where the file_gamma and screen_gamma
  * are not close reciprocals, otherwise it slows things down slightly, and
  * also needlessly introduces small errors.

+ *
+ * We will turn off gamma transformation later if no semitransparent entries
+ * are present in the tRNS array for palette images.  We can't do it here
+ * because we don't necessarily have the tRNS chunk yet.

  */
  */

-void
+void PNGAPI

 png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
 {
 png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
 {

-   png_debug(1, "in png_set_gamma\n");
-   if (fabs(scrn_gamma * file_gamma - 1.0) > PNG_GAMMA_THRESHOLD)
-      png_ptr->transformations |= PNG_GAMMA;
+   png_debug(1, "in png_set_gamma");
+
+   if (png_ptr == NULL)
+      return;
+
+   if ((fabs(scrn_gamma * file_gamma - 1.0) > PNG_GAMMA_THRESHOLD) ||
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) ||
+       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
+     png_ptr->transformations |= PNG_GAMMA;

    png_ptr->gamma = (float)file_gamma;
    png_ptr->screen_gamma = (float)scrn_gamma;
 }
 #endif
 
    png_ptr->gamma = (float)file_gamma;
    png_ptr->screen_gamma = (float)scrn_gamma;
 }
 #endif
 

-#if defined(PNG_READ_EXPAND_SUPPORTED)
-/* Expand paletted images to rgb, expand grayscale images of
- * less than 8 bit depth to 8 bit depth, and expand tRNS chunks
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* Expand paletted images to RGB, expand grayscale images of
+ * less than 8-bit depth to 8-bit depth, and expand tRNS chunks

  * to alpha channels.
  */
  * to alpha channels.
  */

-void
+void PNGAPI

 png_set_expand(png_structp png_ptr)
 {
 png_set_expand(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_expand\n");
+   png_debug(1, "in png_set_expand");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
+}
+
+/* GRR 19990627:  the following three functions currently are identical
+ *  to png_set_expand().  However, it is entirely reasonable that someone
+ *  might wish to expand an indexed image to RGB but *not* expand a single,
+ *  fully transparent palette entry to a full alpha channel--perhaps instead
+ *  convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
+ *  the transparent color with a particular RGB value, or drop tRNS entirely.
+ *  IOW, a future version of the library may make the transformations flag
+ *  a bit more fine-grained, with separate bits for each of these three
+ *  functions.
+ *
+ *  More to the point, these functions make it obvious what libpng will be
+ *  doing, whereas "expand" can (and does) mean any number of things.
+ *
+ *  GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified
+ *  to expand only the sample depth but not to expand the tRNS to alpha
+ *  and its name was changed to png_set_expand_gray_1_2_4_to_8().
+ */
+
+/* Expand paletted images to RGB. */
+void PNGAPI
+png_set_palette_to_rgb(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_palette_to_rgb");
+
+   if (png_ptr == NULL)
+      return;
+
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
+}
+
+/* Expand grayscale images of less than 8-bit depth to 8 bits. */
+void PNGAPI
+png_set_expand_gray_1_2_4_to_8(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
+
+   if (png_ptr == NULL)
+      return;
+

    png_ptr->transformations |= PNG_EXPAND;
    png_ptr->transformations |= PNG_EXPAND;

+   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;

 }
 }

-#endif

 
 

-#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
-void
+
+
+/* Expand tRNS chunks to alpha channels. */
+void PNGAPI
+png_set_tRNS_to_alpha(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_tRNS_to_alpha");
+
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;
+}
+#endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+void PNGAPI

 png_set_gray_to_rgb(png_structp png_ptr)
 {
 png_set_gray_to_rgb(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_gray_to_rgb\n");
+   png_debug(1, "in png_set_gray_to_rgb");
+

    png_ptr->transformations |= PNG_GRAY_TO_RGB;
    png_ptr->transformations |= PNG_GRAY_TO_RGB;

+   png_ptr->flags &= ~PNG_FLAG_ROW_INIT;

 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+#ifdef PNG_FLOATING_POINT_SUPPORTED

 /* Convert a RGB image to a grayscale of the same width.  This allows us,
  * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
  */
 /* Convert a RGB image to a grayscale of the same width.  This allows us,
  * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
  */

-void
-png_set_rgb_to_gray(png_structp png_ptr, int error_action, float red,
-  float green)
+
+void PNGAPI
+png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red,
+   double green)
+{
+   int red_fixed = (int)((float)red*100000.0 + 0.5);
+   int green_fixed = (int)((float)green*100000.0 + 0.5);
+   if (png_ptr == NULL)
+      return;
+   png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed);
+}
+#endif
+
+void PNGAPI
+png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action,
+   png_fixed_point red, png_fixed_point green)

 {
 {

-   png_debug(1, "in png_set_rgb_to_gray\n");
+   png_debug(1, "in png_set_rgb_to_gray");
+
+   if (png_ptr == NULL)
+      return;
+

    switch(error_action)
    {
       case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY;
               break;
    switch(error_action)
    {
       case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY;
               break;

+

       case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
               break;
       case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
               break;

+

       case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
    }
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
    }
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)

-#if defined(PNG_READ_EXPAND_SUPPORTED)
+#ifdef PNG_READ_EXPAND_SUPPORTED

       png_ptr->transformations |= PNG_EXPAND;
 #else
    {
       png_ptr->transformations |= PNG_EXPAND;
 #else
    {

-      png_warning(png_ptr, "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED.");
+      png_warning(png_ptr,
+        "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");

       png_ptr->transformations &= ~PNG_RGB_TO_GRAY;
    }
 #endif
    {
       png_ptr->transformations &= ~PNG_RGB_TO_GRAY;
    }
 #endif
    {

-      png_byte red_byte = (png_byte)(red*255.0 + 0.5);
-      png_byte green_byte = (png_byte)(green*255.0 + 0.5);
-      if(red < 0.0 || green < 0.0)
+      png_uint_16 red_int, green_int;
+      if (red < 0 || green < 0)
+      {
+         red_int   =  6968; /* .212671 * 32768 + .5 */
+         green_int = 23434; /* .715160 * 32768 + .5 */
+      }
+      else if (red + green < 100000L)

       {
       {

-         red_byte = 54;
-         green_byte = 183;
+         red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L);
+         green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L);

       }
       }

-      else if(red_byte + green_byte > 255)
+      else

       {
          png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients");
       {
          png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients");

-         red_byte = 54;
-         green_byte = 183;
+         red_int   =  6968;
+         green_int = 23434;

       }
       }

-      png_ptr->rgb_to_gray_red_coeff   = red_byte;
-      png_ptr->rgb_to_gray_green_coeff = green_byte;
-      png_ptr->rgb_to_gray_blue_coeff  = 255 - red_byte - green_byte;
+      png_ptr->rgb_to_gray_red_coeff   = red_int;
+      png_ptr->rgb_to_gray_green_coeff = green_int;
+      png_ptr->rgb_to_gray_blue_coeff  =
+         (png_uint_16)(32768 - red_int - green_int);

    }
 }
 #endif
 
    }
 }
 #endif
 

-#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
-void
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+void PNGAPI

 png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
    read_user_transform_fn)
 {
 png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
    read_user_transform_fn)
 {

-   png_debug(1, "in png_set_read_user_transform_fn\n");
+   png_debug(1, "in png_set_read_user_transform_fn");
+
+   if (png_ptr == NULL)
+      return;
+
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED

    png_ptr->transformations |= PNG_USER_TRANSFORM;
    png_ptr->read_user_transform_fn = read_user_transform_fn;
    png_ptr->transformations |= PNG_USER_TRANSFORM;
    png_ptr->read_user_transform_fn = read_user_transform_fn;

+#endif

 }
 #endif
 
 /* Initialize everything needed for the read.  This includes modifying
  * the palette.
  */
 }
 #endif
 
 /* Initialize everything needed for the read.  This includes modifying
  * the palette.
  */

-void
+void /* PRIVATE */

 png_init_read_transformations(png_structp png_ptr)
 {
 png_init_read_transformations(png_structp png_ptr)
 {

-   png_debug(1, "in png_init_read_transformations\n");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-   if(png_ptr != NULL)
-#endif
+   png_debug(1, "in png_init_read_transformations");
+

   {
   {

-#if defined(PNG_READ_BACKGROUND_SUPPORTED) || defined(PNG_READ_SHIFT_SUPPORTED) \
- || defined(PNG_READ_GAMMA_SUPPORTED)
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+    defined(PNG_READ_SHIFT_SUPPORTED) || \
+    defined(PNG_READ_GAMMA_SUPPORTED)

    int color_type = png_ptr->color_type;
 #endif
 
 #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
    int color_type = png_ptr->color_type;
 #endif
 
 #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)

-   if (png_ptr->transformations & PNG_BACKGROUND_EXPAND)
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   /* Detect gray background and attempt to enable optimization
+    * for gray --> RGB case
+    *
+    * Note:  if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
+    * RGB_ALPHA (in which case need_expand is superfluous anyway), the
+    * background color might actually be gray yet not be flagged as such.
+    * This is not a problem for the current code, which uses
+    * PNG_BACKGROUND_IS_GRAY only to decide when to do the
+    * png_do_gray_to_rgb() transformation.
+    */
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+       !(color_type & PNG_COLOR_MASK_COLOR))
+   {
+          png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+   } else if ((png_ptr->transformations & PNG_BACKGROUND) &&
+              !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+              (png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+              png_ptr->background.red == png_ptr->background.green &&
+              png_ptr->background.red == png_ptr->background.blue)
+   {
+          png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+          png_ptr->background.gray = png_ptr->background.red;
+   }
+#endif
+
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+       (png_ptr->transformations & PNG_EXPAND))

    {
       if (!(color_type & PNG_COLOR_MASK_COLOR))  /* i.e., GRAY or GRAY_ALPHA */
       {
    {
       if (!(color_type & PNG_COLOR_MASK_COLOR))  /* i.e., GRAY or GRAY_ALPHA */
       {

-         /* expand background chunk. */
+         /* Expand background and tRNS chunks */

          switch (png_ptr->bit_depth)
          {
             case 1:
                png_ptr->background.gray *= (png_uint_16)0xff;
          switch (png_ptr->bit_depth)
          {
             case 1:
                png_ptr->background.gray *= (png_uint_16)0xff;

-               png_ptr->background.red = png_ptr->background.green =
-               png_ptr->background.blue = png_ptr->background.gray;
+               png_ptr->background.red = png_ptr->background.green
+                 =  png_ptr->background.blue = png_ptr->background.gray;
+               if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+               {
+                 png_ptr->trans_color.gray *= (png_uint_16)0xff;
+                 png_ptr->trans_color.red = png_ptr->trans_color.green
+                   = png_ptr->trans_color.blue = png_ptr->trans_color.gray;
+               }

                break;
                break;

+

             case 2:
                png_ptr->background.gray *= (png_uint_16)0x55;
             case 2:
                png_ptr->background.gray *= (png_uint_16)0x55;

-               png_ptr->background.red = png_ptr->background.green =
-               png_ptr->background.blue = png_ptr->background.gray;
+               png_ptr->background.red = png_ptr->background.green
+                 = png_ptr->background.blue = png_ptr->background.gray;
+               if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+               {
+                 png_ptr->trans_color.gray *= (png_uint_16)0x55;
+                 png_ptr->trans_color.red = png_ptr->trans_color.green
+                   = png_ptr->trans_color.blue = png_ptr->trans_color.gray;
+               }

                break;
                break;

+

             case 4:
                png_ptr->background.gray *= (png_uint_16)0x11;
             case 4:
                png_ptr->background.gray *= (png_uint_16)0x11;

-               png_ptr->background.red = png_ptr->background.green =
-               png_ptr->background.blue = png_ptr->background.gray;
+               png_ptr->background.red = png_ptr->background.green
+                 = png_ptr->background.blue = png_ptr->background.gray;
+               if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+               {
+                 png_ptr->trans_color.gray *= (png_uint_16)0x11;
+                 png_ptr->trans_color.red = png_ptr->trans_color.green
+                   = png_ptr->trans_color.blue = png_ptr->trans_color.gray;
+               }

                break;
                break;

+

             case 8:
             case 8:

+

             case 16:
             case 16:

-               png_ptr->background.red = png_ptr->background.green =
-               png_ptr->background.blue = png_ptr->background.gray;
+               png_ptr->background.red = png_ptr->background.green
+                 = png_ptr->background.blue = png_ptr->background.gray;

                break;
          }
       }
                break;
          }
       }


@@ -665,19 +845,20 @@ png_init_read_transformations(png_structp png_ptr)
          png_ptr->background.blue  =
             png_ptr->palette[png_ptr->background.index].blue;
 
          png_ptr->background.blue  =
             png_ptr->palette[png_ptr->background.index].blue;
 

-#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED

         if (png_ptr->transformations & PNG_INVERT_ALPHA)
         {
         if (png_ptr->transformations & PNG_INVERT_ALPHA)
         {

-#if defined(PNG_READ_EXPAND_SUPPORTED)
-           if (!(png_ptr->transformations & PNG_EXPAND))
+#ifdef PNG_READ_EXPAND_SUPPORTED
+           if (!(png_ptr->transformations & PNG_EXPAND_tRNS))

 #endif
            {
 #endif
            {

-           /* invert the alpha channel (in tRNS) unless the pixels are
-              going to be expanded, in which case leave it for later */
-              int i,istop;
+           /* Invert the alpha channel (in tRNS) unless the pixels are
+            * going to be expanded, in which case leave it for later
+            */
+              int i, istop;

               istop=(int)png_ptr->num_trans;
               for (i=0; i<istop; i++)
               istop=(int)png_ptr->num_trans;
               for (i=0; i<istop; i++)

-                 png_ptr->trans[i] = 255 - png_ptr->trans[i];
+                 png_ptr->trans_alpha[i] = (png_byte)(255 - png_ptr->trans_alpha[i]);

            }
         }
 #endif
            }
         }
 #endif


@@ -686,23 +867,41 @@ png_init_read_transformations(png_structp png_ptr)
    }
 #endif
 
    }
 #endif
 

-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)

    png_ptr->background_1 = png_ptr->background;
 #endif
    png_ptr->background_1 = png_ptr->background;
 #endif

-#if defined(PNG_READ_GAMMA_SUPPORTED)
-   if (png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY))
+#if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
+
+   if ((color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_trans != 0)
+       && (fabs(png_ptr->screen_gamma * png_ptr->gamma - 1.0)
+         < PNG_GAMMA_THRESHOLD))

    {
    {

-      png_build_gamma_table(png_ptr);
-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+    int i, k;
+    k=0;
+    for (i=0; i<png_ptr->num_trans; i++)
+    {
+      if (png_ptr->trans_alpha[i] != 0 && png_ptr->trans_alpha[i] != 0xff)
+        k=1; /* Partial transparency is present */
+    }
+    if (k == 0)
+      png_ptr->transformations &= ~PNG_GAMMA;
+   }
+
+   if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) &&
+        png_ptr->gamma != 0.0)
+   {
+      png_build_gamma_table(png_ptr, png_ptr->bit_depth);
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED

       if (png_ptr->transformations & PNG_BACKGROUND)
       {
          if (color_type == PNG_COLOR_TYPE_PALETTE)
          {
       if (png_ptr->transformations & PNG_BACKGROUND)
       {
          if (color_type == PNG_COLOR_TYPE_PALETTE)
          {

+           /* Could skip if no transparency */

             png_color back, back_1;
             png_colorp palette = png_ptr->palette;
             int num_palette = png_ptr->num_palette;
             int i;
             png_color back, back_1;
             png_colorp palette = png_ptr->palette;
             int num_palette = png_ptr->num_palette;
             int i;

-

             if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
             {
                back.red = png_ptr->gamma_table[png_ptr->background.red];
             if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
             {
                back.red = png_ptr->gamma_table[png_ptr->background.red];


@@ -723,10 +922,12 @@ png_init_read_transformations(png_structp png_ptr)
                      g = (png_ptr->screen_gamma);
                      gs = 1.0;
                      break;
                      g = (png_ptr->screen_gamma);
                      gs = 1.0;
                      break;

+

                   case PNG_BACKGROUND_GAMMA_FILE:
                      g = 1.0 / (png_ptr->gamma);
                      gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
                      break;
                   case PNG_BACKGROUND_GAMMA_FILE:
                      g = 1.0 / (png_ptr->gamma);
                      gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
                      break;

+

                   case PNG_BACKGROUND_GAMMA_UNIQUE:
                      g = 1.0 / (png_ptr->background_gamma);
                      gs = 1.0 / (png_ptr->background_gamma *
                   case PNG_BACKGROUND_GAMMA_UNIQUE:
                      g = 1.0 / (png_ptr->background_gamma);
                      gs = 1.0 / (png_ptr->background_gamma *


@@ -746,43 +947,43 @@ png_init_read_transformations(png_structp png_ptr)
                else
                {
                   back.red = (png_byte)(pow(
                else
                {
                   back.red = (png_byte)(pow(

-                     (double)png_ptr->background.red/255, gs) * 255.0 + .5);
+                     (double)png_ptr->background.red/255.0, gs) * 255.0 + .5);

                   back.green = (png_byte)(pow(
                   back.green = (png_byte)(pow(

-                     (double)png_ptr->background.green/255, gs) * 255.0 + .5);
+                     (double)png_ptr->background.green/255.0, gs) * 255.0
+                         + .5);

                   back.blue = (png_byte)(pow(
                   back.blue = (png_byte)(pow(

-                     (double)png_ptr->background.blue/255, gs) * 255.0 + .5);
+                     (double)png_ptr->background.blue/255.0, gs) * 255.0 + .5);

                }
 
                back_1.red = (png_byte)(pow(
                }
 
                back_1.red = (png_byte)(pow(

-                  (double)png_ptr->background.red/255, g) * 255.0 + .5);
+                  (double)png_ptr->background.red/255.0, g) * 255.0 + .5);

                back_1.green = (png_byte)(pow(
                back_1.green = (png_byte)(pow(

-                  (double)png_ptr->background.green/255, g) * 255.0 + .5);
+                  (double)png_ptr->background.green/255.0, g) * 255.0 + .5);

                back_1.blue = (png_byte)(pow(
                back_1.blue = (png_byte)(pow(

-                  (double)png_ptr->background.blue/255, g) * 255.0 + .5);
+                  (double)png_ptr->background.blue/255.0, g) * 255.0 + .5);

             }
             }

-

             for (i = 0; i < num_palette; i++)
             {
             for (i = 0; i < num_palette; i++)
             {

-               if (i < (int)png_ptr->num_trans && png_ptr->trans[i] != 0xff)
+               if (i < (int)png_ptr->num_trans && png_ptr->trans_alpha[i] != 0xff)

                {
                {

-                  if (png_ptr->trans[i] == 0)
+                  if (png_ptr->trans_alpha[i] == 0)

                   {
                      palette[i] = back;
                   }
                   {
                      palette[i] = back;
                   }

-                  else /* if (png_ptr->trans[i] != 0xff) */
+                  else /* if (png_ptr->trans_alpha[i] != 0xff) */

                   {
                      png_byte v, w;
 
                      v = png_ptr->gamma_to_1[palette[i].red];
                   {
                      png_byte v, w;
 
                      v = png_ptr->gamma_to_1[palette[i].red];

-                     png_composite(w, v, png_ptr->trans[i], back_1.red);
+                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.red);

                      palette[i].red = png_ptr->gamma_from_1[w];
 
                      v = png_ptr->gamma_to_1[palette[i].green];
                      palette[i].red = png_ptr->gamma_from_1[w];
 
                      v = png_ptr->gamma_to_1[palette[i].green];

-                     png_composite(w, v, png_ptr->trans[i], back_1.green);
+                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.green);

                      palette[i].green = png_ptr->gamma_from_1[w];
 
                      v = png_ptr->gamma_to_1[palette[i].blue];
                      palette[i].green = png_ptr->gamma_from_1[w];
 
                      v = png_ptr->gamma_to_1[palette[i].blue];

-                     png_composite(w, v, png_ptr->trans[i], back_1.blue);
+                     png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue);

                      palette[i].blue = png_ptr->gamma_from_1[w];
                   }
                }
                      palette[i].blue = png_ptr->gamma_from_1[w];
                   }
                }


@@ -793,8 +994,16 @@ png_init_read_transformations(png_structp png_ptr)
                   palette[i].blue = png_ptr->gamma_table[palette[i].blue];
                }
             }
                   palette[i].blue = png_ptr->gamma_table[palette[i].blue];
                }
             }

+            /* Prevent the transformations being done again, and make sure
+             * that the now spurious alpha channel is stripped - the code
+             * has just reduced background composition and gamma correction
+             * to a simple alpha channel strip.
+             */
+            png_ptr->transformations &= ~PNG_BACKGROUND;
+            png_ptr->transformations &= ~PNG_GAMMA;
+            png_ptr->transformations |= PNG_STRIP_ALPHA;

          }
          }

-         /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN)*/
+         /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */

          else
          /* color_type != PNG_COLOR_TYPE_PALETTE */
          {
          else
          /* color_type != PNG_COLOR_TYPE_PALETTE */
          {


@@ -808,10 +1017,12 @@ png_init_read_transformations(png_structp png_ptr)
                   g = (png_ptr->screen_gamma);
                   gs = 1.0;
                   break;
                   g = (png_ptr->screen_gamma);
                   gs = 1.0;
                   break;

+

                case PNG_BACKGROUND_GAMMA_FILE:
                   g = 1.0 / (png_ptr->gamma);
                   gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
                   break;
                case PNG_BACKGROUND_GAMMA_FILE:
                   g = 1.0 / (png_ptr->gamma);
                   gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
                   break;

+

                case PNG_BACKGROUND_GAMMA_UNIQUE:
                   g = 1.0 / (png_ptr->background_gamma);
                   gs = 1.0 / (png_ptr->background_gamma *
                case PNG_BACKGROUND_GAMMA_UNIQUE:
                   g = 1.0 / (png_ptr->background_gamma);
                   gs = 1.0 / (png_ptr->background_gamma *


@@ -819,9 +1030,16 @@ png_init_read_transformations(png_structp png_ptr)
                   break;
             }
 
                   break;
             }
 

-            if (color_type & PNG_COLOR_MASK_COLOR)
+            png_ptr->background_1.gray = (png_uint_16)(pow(
+               (double)png_ptr->background.gray / m, g) * m + .5);
+            png_ptr->background.gray = (png_uint_16)(pow(
+               (double)png_ptr->background.gray / m, gs) * m + .5);
+
+            if ((png_ptr->background.red != png_ptr->background.green) ||
+                (png_ptr->background.red != png_ptr->background.blue) ||
+                (png_ptr->background.red != png_ptr->background.gray))

             {
             {

-               /* RGB or RGBA */
+               /* RGB or RGBA with color background */

                png_ptr->background_1.red = (png_uint_16)(pow(
                   (double)png_ptr->background.red / m, g) * m + .5);
                png_ptr->background_1.green = (png_uint_16)(pow(
                png_ptr->background_1.red = (png_uint_16)(pow(
                   (double)png_ptr->background.red / m, g) * m + .5);
                png_ptr->background_1.green = (png_uint_16)(pow(


@@ -837,17 +1055,17 @@ png_init_read_transformations(png_structp png_ptr)
             }
             else
             {
             }
             else
             {

-               /* GRAY or GRAY ALPHA */
-               png_ptr->background_1.gray = (png_uint_16)(pow(
-                  (double)png_ptr->background.gray / m, g) * m + .5);
-               png_ptr->background.gray = (png_uint_16)(pow(
-                  (double)png_ptr->background.gray / m, gs) * m + .5);
+               /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
+               png_ptr->background_1.red = png_ptr->background_1.green
+                 = png_ptr->background_1.blue = png_ptr->background_1.gray;
+               png_ptr->background.red = png_ptr->background.green
+                 = png_ptr->background.blue = png_ptr->background.gray;

             }
          }
       }
       else
             }
          }
       }
       else

-      /* transformation does not include PNG_BACKGROUND */
-#endif
+      /* Transformation does not include PNG_BACKGROUND */
+#endif /* PNG_READ_BACKGROUND_SUPPORTED */

       if (color_type == PNG_COLOR_TYPE_PALETTE)
       {
          png_colorp palette = png_ptr->palette;
       if (color_type == PNG_COLOR_TYPE_PALETTE)
       {
          png_colorp palette = png_ptr->palette;


@@ -860,16 +1078,19 @@ png_init_read_transformations(png_structp png_ptr)
             palette[i].green = png_ptr->gamma_table[palette[i].green];
             palette[i].blue = png_ptr->gamma_table[palette[i].blue];
          }
             palette[i].green = png_ptr->gamma_table[palette[i].green];
             palette[i].blue = png_ptr->gamma_table[palette[i].blue];
          }

+
+         /* Done the gamma correction. */
+         png_ptr->transformations &= ~PNG_GAMMA;

       }
    }
       }
    }

-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+#ifdef PNG_READ_BACKGROUND_SUPPORTED

    else
 #endif
    else
 #endif

-#endif
-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+#endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */
+#ifdef PNG_READ_BACKGROUND_SUPPORTED

    /* No GAMMA transformation */
    /* No GAMMA transformation */

-   if (png_ptr->transformations & PNG_BACKGROUND &&
-       color_type == PNG_COLOR_TYPE_PALETTE)
+   if ((png_ptr->transformations & PNG_BACKGROUND) &&
+       (color_type == PNG_COLOR_TYPE_PALETTE))

    {
       int i;
       int istop = (int)png_ptr->num_trans;
    {
       int i;
       int istop = (int)png_ptr->num_trans;


@@ -882,27 +1103,31 @@ png_init_read_transformations(png_structp png_ptr)
 
       for (i = 0; i < istop; i++)
       {
 
       for (i = 0; i < istop; i++)
       {

-         if (png_ptr->trans[i] == 0)
+         if (png_ptr->trans_alpha[i] == 0)

          {
             palette[i] = back;
          }
          {
             palette[i] = back;
          }

-         else if (png_ptr->trans[i] != 0xff)
+         else if (png_ptr->trans_alpha[i] != 0xff)

          {
             /* The png_composite() macro is defined in png.h */
             png_composite(palette[i].red, palette[i].red,
          {
             /* The png_composite() macro is defined in png.h */
             png_composite(palette[i].red, palette[i].red,

-               png_ptr->trans[i], back.red);
+               png_ptr->trans_alpha[i], back.red);

             png_composite(palette[i].green, palette[i].green,
             png_composite(palette[i].green, palette[i].green,

-               png_ptr->trans[i], back.green);
+               png_ptr->trans_alpha[i], back.green);

             png_composite(palette[i].blue, palette[i].blue,
             png_composite(palette[i].blue, palette[i].blue,

-               png_ptr->trans[i], back.blue);
+               png_ptr->trans_alpha[i], back.blue);

          }
       }
          }
       }

+
+      /* Handled alpha, still need to strip the channel. */
+      png_ptr->transformations &= ~PNG_BACKGROUND;
+      png_ptr->transformations |= PNG_STRIP_ALPHA;

    }
    }

-#endif
+#endif /* PNG_READ_BACKGROUND_SUPPORTED */

 
 

-#if defined(PNG_READ_SHIFT_SUPPORTED)
+#ifdef PNG_READ_SHIFT_SUPPORTED

    if ((png_ptr->transformations & PNG_SHIFT) &&
    if ((png_ptr->transformations & PNG_SHIFT) &&

-      color_type == PNG_COLOR_TYPE_PALETTE)
+      (color_type == PNG_COLOR_TYPE_PALETTE))

    {
       png_uint_16 i;
       png_uint_16 istop = png_ptr->num_palette;
    {
       png_uint_16 i;
       png_uint_16 istop = png_ptr->num_palette;


@@ -923,24 +1148,31 @@ png_init_read_transformations(png_structp png_ptr)
          png_ptr->palette[i].blue >>= sb;
       }
    }
          png_ptr->palette[i].blue >>= sb;
       }
    }

-#endif
+#endif  /* PNG_READ_SHIFT_SUPPORTED */

  }
  }

+#if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \
+ && !defined(PNG_READ_BACKGROUND_SUPPORTED)
+   if (png_ptr)
+      return;
+#endif

 }
 
 /* Modify the info structure to reflect the transformations.  The
  * info should be updated so a PNG file could be written with it,
  * assuming the transformations result in valid PNG data.
  */
 }
 
 /* Modify the info structure to reflect the transformations.  The
  * info should be updated so a PNG file could be written with it,
  * assuming the transformations result in valid PNG data.
  */

-void
+void /* PRIVATE */

 png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
 {
 png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
 {

-   png_debug(1, "in png_read_transform_info\n");
-#if defined(PNG_READ_EXPAND_SUPPORTED)
+   png_debug(1, "in png_read_transform_info");
+
+#ifdef PNG_READ_EXPAND_SUPPORTED

    if (png_ptr->transformations & PNG_EXPAND)
    {
       if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       {
    if (png_ptr->transformations & PNG_EXPAND)
    {
       if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       {

-         if (png_ptr->num_trans)
+         if (png_ptr->num_trans &&
+              (png_ptr->transformations & PNG_EXPAND_tRNS))

             info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
          else
             info_ptr->color_type = PNG_COLOR_TYPE_RGB;
             info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
          else
             info_ptr->color_type = PNG_COLOR_TYPE_RGB;


@@ -950,7 +1182,10 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
       else
       {
          if (png_ptr->num_trans)
       else
       {
          if (png_ptr->num_trans)

-            info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+         {
+            if (png_ptr->transformations & PNG_EXPAND_tRNS)
+              info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+         }

          if (info_ptr->bit_depth < 8)
             info_ptr->bit_depth = 8;
          info_ptr->num_trans = 0;
          if (info_ptr->bit_depth < 8)
             info_ptr->bit_depth = 8;
          info_ptr->num_trans = 0;


@@ -958,7 +1193,7 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
    }
 #endif
 
    }
 #endif
 

-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+#ifdef PNG_READ_BACKGROUND_SUPPORTED

    if (png_ptr->transformations & PNG_BACKGROUND)
    {
       info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
    if (png_ptr->transformations & PNG_BACKGROUND)
    {
       info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;


@@ -967,43 +1202,50 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
    }
 #endif
 
    }
 #endif
 

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

    if (png_ptr->transformations & PNG_GAMMA)
    if (png_ptr->transformations & PNG_GAMMA)

+   {
+#ifdef PNG_FLOATING_POINT_SUPPORTED

       info_ptr->gamma = png_ptr->gamma;
 #endif
       info_ptr->gamma = png_ptr->gamma;
 #endif

-
-#if defined(PNG_READ_16_TO_8_SUPPORTED)
-   if ((png_ptr->transformations & PNG_16_TO_8) && info_ptr->bit_depth == 16)
-      info_ptr->bit_depth = 8;
+#ifdef PNG_FIXED_POINT_SUPPORTED
+      info_ptr->int_gamma = png_ptr->int_gamma;

 #endif
 #endif

-
-#if defined(PNG_READ_DITHER_SUPPORTED)
-   if (png_ptr->transformations & PNG_DITHER)
-   {
-      if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
-         (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
-         png_ptr->palette_lookup && info_ptr->bit_depth == 8)
-      {
-         info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
-      }

    }
 #endif
 
    }
 #endif
 

-#if defined(PNG_READ_PACK_SUPPORTED)
-   if ((png_ptr->transformations & PNG_PACK) && info_ptr->bit_depth < 8)
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+   if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16))

       info_ptr->bit_depth = 8;
 #endif
 
       info_ptr->bit_depth = 8;
 #endif
 

-#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED

    if (png_ptr->transformations & PNG_GRAY_TO_RGB)
       info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
 #endif
 
    if (png_ptr->transformations & PNG_GRAY_TO_RGB)
       info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
 #endif
 

-#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED

    if (png_ptr->transformations & PNG_RGB_TO_GRAY)
       info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR;
 #endif
 
    if (png_ptr->transformations & PNG_RGB_TO_GRAY)
       info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR;
 #endif
 

+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   if (png_ptr->transformations & PNG_QUANTIZE)
+   {
+      if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
+          (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
+          png_ptr->palette_lookup && info_ptr->bit_depth == 8)
+      {
+         info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
+      }
+   }
+#endif
+
+#ifdef PNG_READ_PACK_SUPPORTED
+   if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
+      info_ptr->bit_depth = 8;
+#endif
+

    if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       info_ptr->channels = 1;
    else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
    if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       info_ptr->channels = 1;
    else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)


@@ -1011,63 +1253,98 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
    else
       info_ptr->channels = 1;
 
    else
       info_ptr->channels = 1;
 

-#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
-   if (png_ptr->transformations & PNG_STRIP_ALPHA)
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)

       info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
 #endif
 
    if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
       info_ptr->channels++;
 
       info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
 #endif
 
    if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
       info_ptr->channels++;
 

-#if defined(PNG_READ_FILLER_SUPPORTED)
+#ifdef PNG_READ_FILLER_SUPPORTED

    /* STRIP_ALPHA and FILLER allowed:  MASK_ALPHA bit stripped above */
    /* STRIP_ALPHA and FILLER allowed:  MASK_ALPHA bit stripped above */

-   if (png_ptr->transformations & PNG_FILLER &&
-       (info_ptr->color_type == PNG_COLOR_TYPE_RGB ||
-        info_ptr->color_type == PNG_COLOR_TYPE_GRAY))
-      ++info_ptr->channels;
+   if ((png_ptr->transformations & PNG_FILLER) &&
+       ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
+       (info_ptr->color_type == PNG_COLOR_TYPE_GRAY)))
+   {
+      info_ptr->channels++;
+      /* If adding a true alpha channel not just filler */
+      if (png_ptr->transformations & PNG_ADD_ALPHA)
+        info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+   }
+#endif
+
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
+defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+   if (png_ptr->transformations & PNG_USER_TRANSFORM)
+     {
+       if (info_ptr->bit_depth < png_ptr->user_transform_depth)
+         info_ptr->bit_depth = png_ptr->user_transform_depth;
+       if (info_ptr->channels < png_ptr->user_transform_channels)
+         info_ptr->channels = png_ptr->user_transform_channels;
+     }

 #endif
 
    info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
       info_ptr->bit_depth);
 #endif
 
    info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
       info_ptr->bit_depth);

-   info_ptr->rowbytes = ((info_ptr->width * info_ptr->pixel_depth + 7) >> 3);
+
+   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
+
+#ifndef PNG_READ_EXPAND_SUPPORTED
+   if (png_ptr)
+      return;
+#endif

 }
 
 /* Transform the row.  The order of transformations is significant,
  * and is very touchy.  If you add a transformation, take care to
  * decide how it fits in with the other transformations here.
  */
 }
 
 /* Transform the row.  The order of transformations is significant,
  * and is very touchy.  If you add a transformation, take care to
  * decide how it fits in with the other transformations here.
  */

-void
+void /* PRIVATE */

 png_do_read_transformations(png_structp png_ptr)
 {
 png_do_read_transformations(png_structp png_ptr)
 {

-   png_debug(1, "in png_do_read_transformations\n");
-#if !defined(PNG_USELESS_TESTS_SUPPORTED)
+   png_debug(1, "in png_do_read_transformations");
+

    if (png_ptr->row_buf == NULL)
    {
    if (png_ptr->row_buf == NULL)
    {

-#if !defined(PNG_NO_STDIO)
+#ifdef PNG_STDIO_SUPPORTED

       char msg[50];
 
       char msg[50];
 

-      sprintf(msg, "NULL row buffer for row %ld, pass %d", png_ptr->row_number,
+      png_snprintf2(msg, 50,
+         "NULL row buffer for row %ld, pass %d", (long)png_ptr->row_number,

          png_ptr->pass);
       png_error(png_ptr, msg);
 #else
       png_error(png_ptr, "NULL row buffer");
 #endif
    }
          png_ptr->pass);
       png_error(png_ptr, msg);
 #else
       png_error(png_ptr, "NULL row buffer");
 #endif
    }

+#ifdef PNG_WARN_UNINITIALIZED_ROW
+   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
+      /* Application has failed to call either png_read_start_image()
+       * or png_read_update_info() after setting transforms that expand
+       * pixels.  This check added to libpng-1.2.19
+       */
+#if (PNG_WARN_UNINITIALIZED_ROW==1)
+      png_error(png_ptr, "Uninitialized row");
+#else
+      png_warning(png_ptr, "Uninitialized row");
+#endif

 #endif
 
 #endif
 

-#if defined(PNG_READ_EXPAND_SUPPORTED)
+#ifdef PNG_READ_EXPAND_SUPPORTED

    if (png_ptr->transformations & PNG_EXPAND)
    {
       if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE)
       {
          png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1,
    if (png_ptr->transformations & PNG_EXPAND)
    {
       if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE)
       {
          png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1,

-            png_ptr->palette, png_ptr->trans, png_ptr->num_trans);
+            png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);

       }
       else
       {
       }
       else
       {

-         if (png_ptr->num_trans)
+         if (png_ptr->num_trans &&
+             (png_ptr->transformations & PNG_EXPAND_tRNS))

             png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
             png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,

-               &(png_ptr->trans_values));
+               &(png_ptr->trans_color));

          else
             png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
                NULL);
          else
             png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
                NULL);


@@ -1075,194 +1352,211 @@ png_do_read_transformations(png_structp png_ptr)
    }
 #endif
 
    }
 #endif
 

-#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
-   if (png_ptr->transformations & PNG_STRIP_ALPHA)
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+   if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)

       png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
       png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,

-         PNG_FLAG_FILLER_AFTER);
+         PNG_FLAG_FILLER_AFTER | (png_ptr->flags & PNG_FLAG_STRIP_ALPHA));

 #endif
 
 #endif
 

-#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED

    if (png_ptr->transformations & PNG_RGB_TO_GRAY)
    {
       int rgb_error =
    if (png_ptr->transformations & PNG_RGB_TO_GRAY)
    {
       int rgb_error =

-         png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info), png_ptr->row_buf + 1);
-      if(rgb_error)
+         png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info),
+             png_ptr->row_buf + 1);
+      if (rgb_error)

       {
          png_ptr->rgb_to_gray_status=1;
       {
          png_ptr->rgb_to_gray_status=1;

-         if(png_ptr->transformations == PNG_RGB_TO_GRAY_WARN)
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+             PNG_RGB_TO_GRAY_WARN)

             png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
             png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");

-         if(png_ptr->transformations == PNG_RGB_TO_GRAY_ERR)
+         if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+             PNG_RGB_TO_GRAY_ERR)

             png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
       }
    }
 #endif
 
             png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
       }
    }
 #endif
 

-/*
-From Andreas Dilger e-mail to png-implement, 26 March 1998:
-
-  In most cases, the "simple transparency" should be done prior to doing
-  gray-to-RGB, or you will have to test 3x as many bytes to check if a
-  pixel is transparent.  You would also need to make sure that the
-  transparency information is upgraded to RGB.
-
-  To summarize, the current flow is:
-  - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
-                                  with background "in place" if transparent,
-                                  convert to RGB if necessary
-  - Gray + alpha -> composite with gray background and remove alpha bytes,
-                                  convert to RGB if necessary
-
-  To support RGB backgrounds for gray images we need:
-  - Gray + simple transparency -> convert to RGB + simple transparency, compare
-                                  3 or 6 bytes and composite with background
-                                  "in place" if transparent (3x compare/pixel
-                                  compared to doing composite with gray bkgrnd)
-  - Gray + alpha -> convert to RGB + alpha, composite with background and
-                                  remove alpha bytes (3x float operations/pixel
-                                  compared with composite on gray background)
-
-  Greg's change will do this.  The reason it wasn't done before is for
-  performance, as this increases the per-pixel operations.  If we would check
-  in advance if the background was gray or RGB, and position the gray-to-RGB
-  transform appropriately, then it would save a lot of work/time.
+/* From Andreas Dilger e-mail to png-implement, 26 March 1998:
+ *
+ *   In most cases, the "simple transparency" should be done prior to doing
+ *   gray-to-RGB, or you will have to test 3x as many bytes to check if a
+ *   pixel is transparent.  You would also need to make sure that the
+ *   transparency information is upgraded to RGB.
+ *
+ *   To summarize, the current flow is:
+ *   - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
+ *                                   with background "in place" if transparent,
+ *                                   convert to RGB if necessary
+ *   - Gray + alpha -> composite with gray background and remove alpha bytes,
+ *                                   convert to RGB if necessary
+ *
+ *   To support RGB backgrounds for gray images we need:
+ *   - Gray + simple transparency -> convert to RGB + simple transparency,
+ *                                   compare 3 or 6 bytes and composite with
+ *                                   background "in place" if transparent
+ *                                   (3x compare/pixel compared to doing
+ *                                   composite with gray bkgrnd)
+ *   - Gray + alpha -> convert to RGB + alpha, composite with background and
+ *                                   remove alpha bytes (3x float
+ *                                   operations/pixel compared with composite
+ *                                   on gray background)
+ *
+ *  Greg's change will do this.  The reason it wasn't done before is for
+ *  performance, as this increases the per-pixel operations.  If we would check
+ *  in advance if the background was gray or RGB, and position the gray-to-RGB
+ *  transform appropriately, then it would save a lot of work/time.

  */
 
  */
 

-#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
-   /* if gray -> RGB, do so now only if background is non-gray; else do later
-    * for performance reasons */
-   if (png_ptr->transformations & PNG_GRAY_TO_RGB &&
-       !(png_ptr->flags & PNG_FLAG_BACKGROUND_IS_GRAY))
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   /* If gray -> RGB, do so now only if background is non-gray; else do later
+    * for performance reasons
+    */
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+       !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))

       png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 
       png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 

-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+#ifdef PNG_READ_BACKGROUND_SUPPORTED

    if ((png_ptr->transformations & PNG_BACKGROUND) &&
       ((png_ptr->num_trans != 0 ) ||
       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA)))
       png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1,
    if ((png_ptr->transformations & PNG_BACKGROUND) &&
       ((png_ptr->num_trans != 0 ) ||
       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA)))
       png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1,

-         &(png_ptr->trans_values), &(png_ptr->background),
-         &(png_ptr->background_1),
+         &(png_ptr->trans_color), &(png_ptr->background)
+#ifdef PNG_READ_GAMMA_SUPPORTED
+         , &(png_ptr->background_1),

          png_ptr->gamma_table, png_ptr->gamma_from_1,
          png_ptr->gamma_to_1, png_ptr->gamma_16_table,
          png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1,
          png_ptr->gamma_table, png_ptr->gamma_from_1,
          png_ptr->gamma_to_1, png_ptr->gamma_16_table,
          png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1,

-         png_ptr->gamma_shift);
+         png_ptr->gamma_shift
+#endif
+);

 #endif
 
 #endif
 

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

    if ((png_ptr->transformations & PNG_GAMMA) &&
    if ((png_ptr->transformations & PNG_GAMMA) &&

-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
-      !((png_ptr->transformations & PNG_BACKGROUND) &&
-      ((png_ptr->num_trans != 0) ||
-      (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+       !((png_ptr->transformations & PNG_BACKGROUND) &&
+       ((png_ptr->num_trans != 0) ||
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&

 #endif
 #endif

-      (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
+       (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))

       png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1,
       png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1,

-         png_ptr->gamma_table, png_ptr->gamma_16_table,
-         png_ptr->gamma_shift);
+          png_ptr->gamma_table, png_ptr->gamma_16_table,
+          png_ptr->gamma_shift);

 #endif
 
 #endif
 

-#if defined(PNG_READ_16_TO_8_SUPPORTED)
+#ifdef PNG_READ_16_TO_8_SUPPORTED

    if (png_ptr->transformations & PNG_16_TO_8)
       png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 
    if (png_ptr->transformations & PNG_16_TO_8)
       png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 

-#if defined(PNG_READ_DITHER_SUPPORTED)
-   if (png_ptr->transformations & PNG_DITHER)
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+   if (png_ptr->transformations & PNG_QUANTIZE)

    {
    {

-      png_do_dither((png_row_infop)&(png_ptr->row_info), png_ptr->row_buf + 1,
-         png_ptr->palette_lookup, png_ptr->dither_index);
-      if(png_ptr->row_info.rowbytes == (png_uint_32)0)
-         png_error(png_ptr, "png_do_dither returned rowbytes=0");
+      png_do_quantize((png_row_infop)&(png_ptr->row_info), png_ptr->row_buf + 1,
+         png_ptr->palette_lookup, png_ptr->quantize_index);
+      if (png_ptr->row_info.rowbytes == (png_uint_32)0)
+         png_error(png_ptr, "png_do_quantize returned rowbytes=0");

    }
 #endif
 
    }
 #endif
 

-#if defined(PNG_READ_INVERT_SUPPORTED)
+#ifdef PNG_READ_INVERT_SUPPORTED

    if (png_ptr->transformations & PNG_INVERT_MONO)
       png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 
    if (png_ptr->transformations & PNG_INVERT_MONO)
       png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 

-#if defined(PNG_READ_SHIFT_SUPPORTED)
+#ifdef PNG_READ_SHIFT_SUPPORTED

    if (png_ptr->transformations & PNG_SHIFT)
       png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1,
          &(png_ptr->shift));
 #endif
 
    if (png_ptr->transformations & PNG_SHIFT)
       png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1,
          &(png_ptr->shift));
 #endif
 

-#if defined(PNG_READ_PACK_SUPPORTED)
+#ifdef PNG_READ_PACK_SUPPORTED

    if (png_ptr->transformations & PNG_PACK)
       png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 
    if (png_ptr->transformations & PNG_PACK)
       png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 

-#if defined(PNG_READ_BGR_SUPPORTED)
+#ifdef PNG_READ_BGR_SUPPORTED

    if (png_ptr->transformations & PNG_BGR)
       png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 
    if (png_ptr->transformations & PNG_BGR)
       png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 

-#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+#ifdef PNG_READ_PACKSWAP_SUPPORTED

    if (png_ptr->transformations & PNG_PACKSWAP)
       png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 
    if (png_ptr->transformations & PNG_PACKSWAP)
       png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 

-#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
-   /* if gray -> RGB, do so now only if we did not do so above */
-   if (png_ptr->transformations & PNG_GRAY_TO_RGB &&
-       png_ptr->flags & PNG_FLAG_BACKGROUND_IS_GRAY)
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   /* If gray -> RGB, do so now only if we did not do so above */
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))

       png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 
       png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 

-#if defined(PNG_READ_FILLER_SUPPORTED)
+#ifdef PNG_READ_FILLER_SUPPORTED

    if (png_ptr->transformations & PNG_FILLER)
       png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
          (png_uint_32)png_ptr->filler, png_ptr->flags);
 #endif
 
    if (png_ptr->transformations & PNG_FILLER)
       png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
          (png_uint_32)png_ptr->filler, png_ptr->flags);
 #endif
 

-#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED

    if (png_ptr->transformations & PNG_INVERT_ALPHA)
       png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 
    if (png_ptr->transformations & PNG_INVERT_ALPHA)
       png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 

-#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED

    if (png_ptr->transformations & PNG_SWAP_ALPHA)
       png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 
    if (png_ptr->transformations & PNG_SWAP_ALPHA)
       png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 

-#if defined(PNG_READ_SWAP_SUPPORTED)
+#ifdef PNG_READ_SWAP_SUPPORTED

    if (png_ptr->transformations & PNG_SWAP_BYTES)
       png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 
    if (png_ptr->transformations & PNG_SWAP_BYTES)
       png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
 #endif
 

-#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+#ifdef PNG_READ_USER_TRANSFORM_SUPPORTED

    if (png_ptr->transformations & PNG_USER_TRANSFORM)
    if (png_ptr->transformations & PNG_USER_TRANSFORM)

-      if(png_ptr->read_user_transform_fn != NULL)
-        (*(png_ptr->read_user_transform_fn)) /* user read transform function */
-          (png_ptr,                    /* png_ptr */
-           &(png_ptr->row_info),       /* row_info:     */
-             /*  png_uint_32 width;          width of row */
-             /*  png_uint_32 rowbytes;       number of bytes in row */
-             /*  png_byte color_type;        color type of pixels */
-             /*  png_byte bit_depth;         bit depth of samples */
-             /*  png_byte channels;          number of channels (1-4) */
-             /*  png_byte pixel_depth;       bits per pixel (depth*channels) */
-           png_ptr->row_buf + 1);      /* start of pixel data for row */
+    {
+      if (png_ptr->read_user_transform_fn != NULL)
+         (*(png_ptr->read_user_transform_fn)) /* User read transform function */
+            (png_ptr,                    /* png_ptr */
+               &(png_ptr->row_info),     /* row_info: */
+               /*  png_uint_32 width;       width of row */
+               /*  png_uint_32 rowbytes;    number of bytes in row */
+               /*  png_byte color_type;     color type of pixels */
+               /*  png_byte bit_depth;      bit depth of samples */
+               /*  png_byte channels;       number of channels (1-4) */
+               /*  png_byte pixel_depth;    bits per pixel (depth*channels) */
+               png_ptr->row_buf + 1);    /* start of pixel data for row */
+#ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
+      if (png_ptr->user_transform_depth)
+         png_ptr->row_info.bit_depth = png_ptr->user_transform_depth;
+      if (png_ptr->user_transform_channels)
+         png_ptr->row_info.channels = png_ptr->user_transform_channels;
+#endif
+      png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
+         png_ptr->row_info.channels);
+      png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
+         png_ptr->row_info.width);
+   }

 #endif
 
 }
 
 #endif
 
 }
 

-#if defined(PNG_READ_PACK_SUPPORTED)
+#ifdef PNG_READ_PACK_SUPPORTED

 /* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
  * without changing the actual values.  Thus, if you had a row with
  * a bit depth of 1, you would end up with bytes that only contained
  * the numbers 0 or 1.  If you would rather they contain 0 and 255, use
  * png_do_shift() after this.
  */
 /* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
  * without changing the actual values.  Thus, if you had a row with
  * a bit depth of 1, you would end up with bytes that only contained
  * the numbers 0 or 1.  If you would rather they contain 0 and 255, use
  * png_do_shift() after this.
  */

-void
+void /* PRIVATE */

 png_do_unpack(png_row_infop row_info, png_bytep row)
 {
 png_do_unpack(png_row_infop row_info, png_bytep row)
 {

-   png_debug(1, "in png_do_unpack\n");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-   if (row != NULL && row_info != NULL && row_info->bit_depth < 8)
-#else
+   png_debug(1, "in png_do_unpack");
+

    if (row_info->bit_depth < 8)
    if (row_info->bit_depth < 8)

-#endif

    {
       png_uint_32 i;
       png_uint_32 row_width=row_info->width;
    {
       png_uint_32 i;
       png_uint_32 row_width=row_info->width;


@@ -1273,10 +1567,10 @@ png_do_unpack(png_row_infop row_info, png_bytep row)
          {
             png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
             png_bytep dp = row + (png_size_t)row_width - 1;
          {
             png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
             png_bytep dp = row + (png_size_t)row_width - 1;

-            png_uint_32 shift = 7 - (int)((row_width + 7) & 7);
+            png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07);

             for (i = 0; i < row_width; i++)
             {
             for (i = 0; i < row_width; i++)
             {

-               *dp = (png_byte)((*sp >> shift) & 0x1);
+               *dp = (png_byte)((*sp >> shift) & 0x01);

                if (shift == 7)
                {
                   shift = 0;
                if (shift == 7)
                {
                   shift = 0;


@@ -1289,15 +1583,16 @@ png_do_unpack(png_row_infop row_info, png_bytep row)
             }
             break;
          }
             }
             break;
          }

+

          case 2:
          {
 
             png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
             png_bytep dp = row + (png_size_t)row_width - 1;
          case 2:
          {
 
             png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
             png_bytep dp = row + (png_size_t)row_width - 1;

-            png_uint_32 shift = (int)((3 - ((row_width + 3) & 3)) << 1);
+            png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);

             for (i = 0; i < row_width; i++)
             {
             for (i = 0; i < row_width; i++)
             {

-               *dp = (png_byte)((*sp >> shift) & 0x3);
+               *dp = (png_byte)((*sp >> shift) & 0x03);

                if (shift == 6)
                {
                   shift = 0;
                if (shift == 6)
                {
                   shift = 0;


@@ -1310,14 +1605,15 @@ png_do_unpack(png_row_infop row_info, png_bytep row)
             }
             break;
          }
             }
             break;
          }

+

          case 4:
          {
             png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
             png_bytep dp = row + (png_size_t)row_width - 1;
          case 4:
          {
             png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
             png_bytep dp = row + (png_size_t)row_width - 1;

-            png_uint_32 shift = (int)((1 - ((row_width + 1) & 1)) << 2);
+            png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);

             for (i = 0; i < row_width; i++)
             {
             for (i = 0; i < row_width; i++)
             {

-               *dp = (png_byte)((*sp >> shift) & 0xf);
+               *dp = (png_byte)((*sp >> shift) & 0x0f);

                if (shift == 4)
                {
                   shift = 0;
                if (shift == 4)
                {
                   shift = 0;


@@ -1338,20 +1634,18 @@ png_do_unpack(png_row_infop row_info, png_bytep row)
 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_SHIFT_SUPPORTED)
+#ifdef PNG_READ_SHIFT_SUPPORTED

 /* Reverse the effects of png_do_shift.  This routine merely shifts the
  * pixels back to their significant bits values.  Thus, if you have
  * a row of bit depth 8, but only 5 are significant, this will shift
  * the values back to 0 through 31.
  */
 /* Reverse the effects of png_do_shift.  This routine merely shifts the
  * pixels back to their significant bits values.  Thus, if you have
  * a row of bit depth 8, but only 5 are significant, this will shift
  * the values back to 0 through 31.
  */

-void
+void /* PRIVATE */

 png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
 {
 png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
 {

-   png_debug(1, "in png_do_unshift\n");
+   png_debug(1, "in png_do_unshift");
+

    if (
    if (

-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-       row != NULL && row_info != NULL && sig_bits != NULL &&
-#endif

        row_info->color_type != PNG_COLOR_TYPE_PALETTE)
    {
       int shift[4];
        row_info->color_type != PNG_COLOR_TYPE_PALETTE)
    {
       int shift[4];


@@ -1401,13 +1695,14 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
             }
             break;
          }
             }
             break;
          }

+

          case 4:
          {
             png_bytep bp = row;
             png_uint_32 i;
             png_uint_32 istop = row_info->rowbytes;
          case 4:
          {
             png_bytep bp = row;
             png_uint_32 i;
             png_uint_32 istop = row_info->rowbytes;

-            png_byte mask = (png_byte)(((int)0xf0 >> shift[0]) & (int)0xf0) |
-               (png_byte)((int)0xf >> shift[0]);
+            png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) |
+               (png_byte)((int)0xf >> shift[0]));

 
             for (i = 0; i < istop; i++)
             {
 
             for (i = 0; i < istop; i++)
             {


@@ -1416,6 +1711,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
             }
             break;
          }
             }
             break;
          }

+

          case 8:
          {
             png_bytep bp = row;
          case 8:
          {
             png_bytep bp = row;


@@ -1428,6 +1724,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
             }
             break;
          }
             }
             break;
          }

+

          case 16:
          {
             png_bytep bp = row;
          case 16:
          {
             png_bytep bp = row;


@@ -1448,17 +1745,14 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_16_TO_8_SUPPORTED)
-/* chop rows of bit depth 16 down to 8 */
-void
+#ifdef PNG_READ_16_TO_8_SUPPORTED
+/* Chop rows of bit depth 16 down to 8 */
+void /* PRIVATE */

 png_do_chop(png_row_infop row_info, png_bytep row)
 {
 png_do_chop(png_row_infop row_info, png_bytep row)
 {

-   png_debug(1, "in png_do_chop\n");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-   if (row != NULL && row_info != NULL && row_info->bit_depth == 16)
-#else
+   png_debug(1, "in png_do_chop");
+

    if (row_info->bit_depth == 16)
    if (row_info->bit_depth == 16)

-#endif

    {
       png_bytep sp = row;
       png_bytep dp = row;
    {
       png_bytep sp = row;
       png_bytep dp = row;


@@ -1467,20 +1761,23 @@ png_do_chop(png_row_infop row_info, png_bytep row)
 
       for (i = 0; i<istop; i++, sp += 2, dp++)
       {
 
       for (i = 0; i<istop; i++, sp += 2, dp++)
       {

-#if defined(PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED)
+#ifdef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED

       /* This does a more accurate scaling of the 16-bit color
        * value, rather than a simple low-byte truncation.
        *
        * What the ideal calculation should be:
        *   *dp = (((((png_uint_32)(*sp) << 8) |
       /* This does a more accurate scaling of the 16-bit color
        * value, rather than a simple low-byte truncation.
        *
        * What the ideal calculation should be:
        *   *dp = (((((png_uint_32)(*sp) << 8) |

-       *          (png_uint_32)(*(sp + 1))) * 255 + 127) / (png_uint_32)65535L;
+       *          (png_uint_32)(*(sp + 1))) * 255 + 127)
+       *          / (png_uint_32)65535L;

        *
        * GRR: no, I think this is what it really should be:
        *   *dp = (((((png_uint_32)(*sp) << 8) |
        *
        * GRR: no, I think this is what it really should be:
        *   *dp = (((((png_uint_32)(*sp) << 8) |

-       *           (png_uint_32)(*(sp + 1))) + 128L) / (png_uint_32)257L;
+       *           (png_uint_32)(*(sp + 1))) + 128L)
+       *           / (png_uint_32)257L;

        *
        * GRR: here's the exact calculation with shifts:
        *
        * GRR: here's the exact calculation with shifts:

-       *   temp = (((png_uint_32)(*sp) << 8) | (png_uint_32)(*(sp + 1))) + 128L;
+       *   temp = (((png_uint_32)(*sp) << 8) |
+       *           (png_uint_32)(*(sp + 1))) + 128L;

        *   *dp = (temp - (temp >> 8)) >> 8;
        *
        * Approximate calculation with shift/add instead of multiply/divide:
        *   *dp = (temp - (temp >> 8)) >> 8;
        *
        * Approximate calculation with shift/add instead of multiply/divide:


@@ -1503,14 +1800,12 @@ png_do_chop(png_row_infop row_info, png_bytep row)
 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
-void
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
+void /* PRIVATE */

 png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
 {
 png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
 {

-   png_debug(1, "in png_do_read_swap_alpha\n");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-   if (row != NULL && row_info != NULL)
-#endif
+   png_debug(1, "in png_do_read_swap_alpha");
+

    {
       png_uint_32 row_width = row_info->width;
       if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
    {
       png_uint_32 row_width = row_info->width;
       if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)


@@ -1595,14 +1890,12 @@ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
-void
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
+void /* PRIVATE */

 png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
 {
 png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
 {

-   png_debug(1, "in png_do_read_invert_alpha\n");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-   if (row != NULL && row_info != NULL)
-#endif
+   png_debug(1, "in png_do_read_invert_alpha");
+

    {
       png_uint_32 row_width = row_info->width;
       if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
    {
       png_uint_32 row_width = row_info->width;
       if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)


@@ -1616,10 +1909,16 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
 
             for (i = 0; i < row_width; i++)
             {
 
             for (i = 0; i < row_width; i++)
             {

-               *(--dp) = 255 - *(--sp);
+               *(--dp) = (png_byte)(255 - *(--sp));
+
+/*             This does nothing:

                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);

+               We can replace it with:
+*/
+               sp-=3;
+               dp=sp;

             }
          }
          /* This inverts the alpha channel in RRGGBBAA */
             }
          }
          /* This inverts the alpha channel in RRGGBBAA */


@@ -1631,14 +1930,20 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
 
             for (i = 0; i < row_width; i++)
             {
 
             for (i = 0; i < row_width; i++)
             {

-               *(--dp) = 255 - *(--sp);
-               *(--dp) = 255 - *(--sp);
+               *(--dp) = (png_byte)(255 - *(--sp));
+               *(--dp) = (png_byte)(255 - *(--sp));
+
+/*             This does nothing:

                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);

+               We can replace it with:
+*/
+               sp-=6;
+               dp=sp;

             }
          }
       }
             }
          }
       }


@@ -1653,7 +1958,7 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
 
             for (i = 0; i < row_width; i++)
             {
 
             for (i = 0; i < row_width; i++)
             {

-               *(--dp) = 255 - *(--sp);
+               *(--dp) = (png_byte)(255 - *(--sp));

                *(--dp) = *(--sp);
             }
          }
                *(--dp) = *(--sp);
             }
          }


@@ -1666,10 +1971,14 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
 
             for (i = 0; i < row_width; i++)
             {
 
             for (i = 0; i < row_width; i++)
             {

-               *(--dp) = 255 - *(--sp);
-               *(--dp) = 255 - *(--sp);
+               *(--dp) = (png_byte)(255 - *(--sp));
+               *(--dp) = (png_byte)(255 - *(--sp));
+/*

                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);
                *(--dp) = *(--sp);

+*/
+               sp-=2;
+               dp=sp;

             }
          }
       }
             }
          }
       }


@@ -1677,9 +1986,9 @@ png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_FILLER_SUPPORTED)
+#ifdef PNG_READ_FILLER_SUPPORTED

 /* Add filler channel if we have RGB color */
 /* Add filler channel if we have RGB color */

-void
+void /* PRIVATE */

 png_do_read_filler(png_row_infop row_info, png_bytep row,
    png_uint_32 filler, png_uint_32 flags)
 {
 png_do_read_filler(png_row_infop row_info, png_bytep row,
    png_uint_32 filler, png_uint_32 flags)
 {


@@ -1689,14 +1998,12 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
    png_byte hi_filler = (png_byte)((filler>>8) & 0xff);
    png_byte lo_filler = (png_byte)(filler & 0xff);
 
    png_byte hi_filler = (png_byte)((filler>>8) & 0xff);
    png_byte lo_filler = (png_byte)(filler & 0xff);
 

-   png_debug(1, "in png_do_read_filler\n");
+   png_debug(1, "in png_do_read_filler");
+

    if (
    if (

-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-       row != NULL  && row_info != NULL &&
-#endif

        row_info->color_type == PNG_COLOR_TYPE_GRAY)
    {
        row_info->color_type == PNG_COLOR_TYPE_GRAY)
    {

-      if(row_info->bit_depth == 8)
+      if (row_info->bit_depth == 8)

       {
          /* This changes the data from G to GX */
          if (flags & PNG_FLAG_FILLER_AFTER)
       {
          /* This changes the data from G to GX */
          if (flags & PNG_FLAG_FILLER_AFTER)


@@ -1728,13 +2035,13 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
             row_info->rowbytes = row_width * 2;
          }
       }
             row_info->rowbytes = row_width * 2;
          }
       }

-      else if(row_info->bit_depth == 16)
+      else if (row_info->bit_depth == 16)

       {
          /* This changes the data from GG to GGXX */
          if (flags & PNG_FLAG_FILLER_AFTER)
          {
       {
          /* This changes the data from GG to GGXX */
          if (flags & PNG_FLAG_FILLER_AFTER)
          {

-            png_bytep sp = row + (png_size_t)row_width;
-            png_bytep dp = sp  + (png_size_t)row_width;
+            png_bytep sp = row + (png_size_t)row_width * 2;
+            png_bytep dp = sp  + (png_size_t)row_width * 2;

             for (i = 1; i < row_width; i++)
             {
                *(--dp) = hi_filler;
             for (i = 1; i < row_width; i++)
             {
                *(--dp) = hi_filler;


@@ -1746,13 +2053,13 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
             *(--dp) = lo_filler;
             row_info->channels = 2;
             row_info->pixel_depth = 32;
             *(--dp) = lo_filler;
             row_info->channels = 2;
             row_info->pixel_depth = 32;

-            row_info->rowbytes = row_width * 2;
+            row_info->rowbytes = row_width * 4;

          }
          /* This changes the data from GG to XXGG */
          else
          {
          }
          /* This changes the data from GG to XXGG */
          else
          {

-            png_bytep sp = row + (png_size_t)row_width;
-            png_bytep dp = sp  + (png_size_t)row_width;
+            png_bytep sp = row + (png_size_t)row_width * 2;
+            png_bytep dp = sp  + (png_size_t)row_width * 2;

             for (i = 0; i < row_width; i++)
             {
                *(--dp) = *(--sp);
             for (i = 0; i < row_width; i++)
             {
                *(--dp) = *(--sp);


@@ -1761,14 +2068,14 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
                *(--dp) = lo_filler;
             }
             row_info->channels = 2;
                *(--dp) = lo_filler;
             }
             row_info->channels = 2;

-            row_info->pixel_depth = 16;
-            row_info->rowbytes = row_width * 2;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;

          }
       }
    } /* COLOR_TYPE == GRAY */
    else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
    {
          }
       }
    } /* COLOR_TYPE == GRAY */
    else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
    {

-      if(row_info->bit_depth == 8)
+      if (row_info->bit_depth == 8)

       {
          /* This changes the data from RGB to RGBX */
          if (flags & PNG_FLAG_FILLER_AFTER)
       {
          /* This changes the data from RGB to RGBX */
          if (flags & PNG_FLAG_FILLER_AFTER)


@@ -1804,13 +2111,13 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
             row_info->rowbytes = row_width * 4;
          }
       }
             row_info->rowbytes = row_width * 4;
          }
       }

-      else if(row_info->bit_depth == 16)
+      else if (row_info->bit_depth == 16)

       {
          /* This changes the data from RRGGBB to RRGGBBXX */
          if (flags & PNG_FLAG_FILLER_AFTER)
          {
       {
          /* This changes the data from RRGGBB to RRGGBBXX */
          if (flags & PNG_FLAG_FILLER_AFTER)
          {

-            png_bytep sp = row + (png_size_t)row_width * 3;
-            png_bytep dp = sp  + (png_size_t)row_width;
+            png_bytep sp = row + (png_size_t)row_width * 6;
+            png_bytep dp = sp  + (png_size_t)row_width * 2;

             for (i = 1; i < row_width; i++)
             {
                *(--dp) = hi_filler;
             for (i = 1; i < row_width; i++)
             {
                *(--dp) = hi_filler;


@@ -1826,13 +2133,13 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
             *(--dp) = lo_filler;
             row_info->channels = 4;
             row_info->pixel_depth = 64;
             *(--dp) = lo_filler;
             row_info->channels = 4;
             row_info->pixel_depth = 64;

-            row_info->rowbytes = row_width * 4;
+            row_info->rowbytes = row_width * 8;

          }
          /* This changes the data from RRGGBB to XXRRGGBB */
          else
          {
          }
          /* This changes the data from RRGGBB to XXRRGGBB */
          else
          {

-            png_bytep sp = row + (png_size_t)row_width * 3;
-            png_bytep dp = sp  + (png_size_t)row_width;
+            png_bytep sp = row + (png_size_t)row_width * 6;
+            png_bytep dp = sp  + (png_size_t)row_width * 2;

             for (i = 0; i < row_width; i++)
             {
                *(--dp) = *(--sp);
             for (i = 0; i < row_width; i++)
             {
                *(--dp) = *(--sp);


@@ -1846,26 +2153,24 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
             }
             row_info->channels = 4;
             row_info->pixel_depth = 64;
             }
             row_info->channels = 4;
             row_info->pixel_depth = 64;

-            row_info->rowbytes = row_width * 4;
+            row_info->rowbytes = row_width * 8;

          }
       }
    } /* COLOR_TYPE == RGB */
 }
 #endif
 
          }
       }
    } /* COLOR_TYPE == RGB */
 }
 #endif
 

-#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
-/* expand grayscale files to RGB, with or without alpha */
-void
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+/* Expand grayscale files to RGB, with or without alpha */
+void /* PRIVATE */

 png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
 {
    png_uint_32 i;
    png_uint_32 row_width = row_info->width;
 
 png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
 {
    png_uint_32 i;
    png_uint_32 row_width = row_info->width;
 

-   png_debug(1, "in png_do_gray_to_rgb\n");
+   png_debug(1, "in png_do_gray_to_rgb");
+

    if (row_info->bit_depth >= 8 &&
    if (row_info->bit_depth >= 8 &&

-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-       row != NULL && row_info != NULL &&
-#endif

       !(row_info->color_type & PNG_COLOR_MASK_COLOR))
    {
       if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
       !(row_info->color_type & PNG_COLOR_MASK_COLOR))
    {
       if (row_info->color_type == PNG_COLOR_TYPE_GRAY)


@@ -1878,8 +2183,7 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
             {
                *(dp--) = *sp;
                *(dp--) = *sp;
             {
                *(dp--) = *sp;
                *(dp--) = *sp;

-               *(dp--) = *sp;
-               sp--;
+               *(dp--) = *(sp--);

             }
          }
          else
             }
          }
          else


@@ -1892,10 +2196,8 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
                *(dp--) = *(sp - 1);
                *(dp--) = *sp;
                *(dp--) = *(sp - 1);
                *(dp--) = *(sp - 1);
                *(dp--) = *sp;
                *(dp--) = *(sp - 1);

-               *(dp--) = *sp;
-               *(dp--) = *(sp - 1);
-               sp--;
-               sp--;
+               *(dp--) = *(sp--);
+               *(dp--) = *(sp--);

             }
          }
       }
             }
          }
       }


@@ -1910,8 +2212,7 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
                *(dp--) = *(sp--);
                *(dp--) = *sp;
                *(dp--) = *sp;
                *(dp--) = *(sp--);
                *(dp--) = *sp;
                *(dp--) = *sp;

-               *(dp--) = *sp;
-               sp--;
+               *(dp--) = *(sp--);

             }
          }
          else
             }
          }
          else


@@ -1926,10 +2227,8 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
                *(dp--) = *(sp - 1);
                *(dp--) = *sp;
                *(dp--) = *(sp - 1);
                *(dp--) = *(sp - 1);
                *(dp--) = *sp;
                *(dp--) = *(sp - 1);

-               *(dp--) = *sp;
-               *(dp--) = *(sp - 1);
-               sp--;
-               sp--;
+               *(dp--) = *(sp--);
+               *(dp--) = *(sp--);

             }
          }
       }
             }
          }
       }


@@ -1937,33 +2236,34 @@ png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
       row_info->color_type |= PNG_COLOR_MASK_COLOR;
       row_info->pixel_depth = (png_byte)(row_info->channels *
          row_info->bit_depth);
       row_info->color_type |= PNG_COLOR_MASK_COLOR;
       row_info->pixel_depth = (png_byte)(row_info->channels *
          row_info->bit_depth);

-      row_info->rowbytes = ((row_width *
-         row_info->pixel_depth + 7) >> 3);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);

    }
 }
 #endif
 
    }
 }
 #endif
 

-#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-/* reduce RGB files to grayscale, with or without alpha 
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* Reduce RGB files to grayscale, with or without alpha

  * using the equation given in Poynton's ColorFAQ at
  * using the equation given in Poynton's ColorFAQ at

- * <http://www.inforamp.net/~poynton/>
- * Copyright (c) 1998-01-04 Charles Poynton poynton@inforamp.net
+ * <http://www.inforamp.net/~poynton/>  (THIS LINK IS DEAD June 2008)
+ * New link:
+ * <http://www.poynton.com/notes/colour_and_gamma/>
+ * Charles Poynton poynton at poynton.com

  *
  *     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
  *
  *  We approximate this with
  *
  *     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
  *
  *  We approximate this with

- * 
- *     Y = 0.211 * R    + 0.715 * G    + 0.074 * B
+ *
+ *     Y = 0.21268 * R    + 0.7151 * G    + 0.07217 * B

  *
  *  which can be expressed with integers as
  *
  *
  *  which can be expressed with integers as
  *

- *     Y = (54 * R + 183 * G + 19 * B)/256
+ *     Y = (6969 * R + 23434 * G + 2365 * B)/32768

  *
  *  The calculation is to be done in a linear colorspace.
  *
  *  Other integer coefficents can be used via png_set_rgb_to_gray().
  */
  *
  *  The calculation is to be done in a linear colorspace.
  *
  *  Other integer coefficents can be used via png_set_rgb_to_gray().
  */

-int
+int /* PRIVATE */

 png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
 
 {
 png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
 
 {


@@ -1972,16 +2272,14 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
    png_uint_32 row_width = row_info->width;
    int rgb_error = 0;
 
    png_uint_32 row_width = row_info->width;
    int rgb_error = 0;
 

-   png_debug(1, "in png_do_rgb_to_gray\n");
+   png_debug(1, "in png_do_rgb_to_gray");
+

    if (
    if (

-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-       row != NULL && row_info != NULL &&
-#endif

       (row_info->color_type & PNG_COLOR_MASK_COLOR))
    {
       (row_info->color_type & PNG_COLOR_MASK_COLOR))
    {

-      png_byte rc = png_ptr->rgb_to_gray_red_coeff;
-      png_byte gc = png_ptr->rgb_to_gray_green_coeff;
-      png_byte bc = png_ptr->rgb_to_gray_blue_coeff;
+      png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
+      png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
+      png_uint_32 bc = png_ptr->rgb_to_gray_blue_coeff;

 
       if (row_info->color_type == PNG_COLOR_TYPE_RGB)
       {
 
       if (row_info->color_type == PNG_COLOR_TYPE_RGB)
       {


@@ -1998,14 +2296,14 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                   png_byte red   = png_ptr->gamma_to_1[*(sp++)];
                   png_byte green = png_ptr->gamma_to_1[*(sp++)];
                   png_byte blue  = png_ptr->gamma_to_1[*(sp++)];
                   png_byte red   = png_ptr->gamma_to_1[*(sp++)];
                   png_byte green = png_ptr->gamma_to_1[*(sp++)];
                   png_byte blue  = png_ptr->gamma_to_1[*(sp++)];

-                  if(red != green || red != blue)
+                  if (red != green || red != blue)

                   {
                      rgb_error |= 1;
                      *(dp++) = png_ptr->gamma_from_1[
                   {
                      rgb_error |= 1;
                      *(dp++) = png_ptr->gamma_from_1[

-                       (rc*red+gc*green+bc*blue)>>8];
+                       (rc*red + gc*green + bc*blue)>>15];

                   }
                   else
                   }
                   else

-                     *(dp++) = *(sp-1);
+                     *(dp++) = *(sp - 1);

                }
             }
             else
                }
             }
             else


@@ -2018,17 +2316,17 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                   png_byte red   = *(sp++);
                   png_byte green = *(sp++);
                   png_byte blue  = *(sp++);
                   png_byte red   = *(sp++);
                   png_byte green = *(sp++);
                   png_byte blue  = *(sp++);

-                  if(red != green || red != blue)
+                  if (red != green || red != blue)

                   {
                      rgb_error |= 1;
                   {
                      rgb_error |= 1;

-                     *(dp++) = (rc*red+gc*green+bc*blue)>>8;
+                     *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);

                   }
                   else
                   }
                   else

-                     *(dp++) = *(sp-1);
+                     *(dp++) = *(sp - 1);

                }
             }
          }
                }
             }
          }

- 
+

          else /* RGB bit_depth == 16 */
          {
 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
          else /* RGB bit_depth == 16 */
          {
 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)


@@ -2041,29 +2339,30 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                {
                   png_uint_16 red, green, blue, w;
 
                {
                   png_uint_16 red, green, blue, w;
 

-                  red   = ((*(sp))<<8) | *(sp+1); sp+=2;
-                  green = ((*(sp))<<8) | *(sp+1); sp+=2;
-                  blue  = ((*(sp))<<8) | *(sp+1); sp+=2;
+                  red   = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  blue  = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;

 
 

-                  if(red == green && red == blue)
+                  if (red == green && red == blue)

                      w = red;
                   else
                   {
                      png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red&0xff) >>
                                   png_ptr->gamma_shift][red>>8];
                      w = red;
                   else
                   {
                      png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red&0xff) >>
                                   png_ptr->gamma_shift][red>>8];

-                     png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >>
+                     png_uint_16 green_1 =
+                         png_ptr->gamma_16_to_1[(green&0xff) >>

                                   png_ptr->gamma_shift][green>>8];
                                   png_ptr->gamma_shift][green>>8];

-                     png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff) >> 
+                     png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff) >>

                                   png_ptr->gamma_shift][blue>>8];
                                   png_ptr->gamma_shift][blue>>8];

-                     png_uint_16 gray16  =  (rc * red_1 + gc * green_1
-                                  + bc * blue_1)>>8;
+                     png_uint_16 gray16  = (png_uint_16)((rc*red_1 + gc*green_1
+                                  + bc*blue_1)>>15);

                      w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
                          png_ptr->gamma_shift][gray16 >> 8];
                      rgb_error |= 1;
                   }
                      w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
                          png_ptr->gamma_shift][gray16 >> 8];
                      rgb_error |= 1;
                   }

-                  
-                  *(dp++) = (w>>8) & 0xff;
-                  *(dp++) = w & 0xff;
+
+                  *(dp++) = (png_byte)((w>>8) & 0xff);
+                  *(dp++) = (png_byte)(w & 0xff);

                }
             }
             else
                }
             }
             else


@@ -2075,15 +2374,15 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                {
                   png_uint_16 red, green, blue, gray16;
 
                {
                   png_uint_16 red, green, blue, gray16;
 

-                  red   = ((*(sp))<<8) | *(sp+1); sp+=2;
-                  green = ((*(sp))<<8) | *(sp+1); sp+=2;
-                  blue  = ((*(sp))<<8) | *(sp+1); sp+=2;
+                  red   = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  blue  = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;

 
 

-                  if(red != green || red != blue)
+                  if (red != green || red != blue)

                      rgb_error |= 1;
                      rgb_error |= 1;

-                  gray16  =  (rc * red + gc * green + bc * blue)>>8;
-                  *(dp++) = (gray16>>8) & 0xff;
-                  *(dp++) = gray16 & 0xff;
+                  gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
+                  *(dp++) = (png_byte)((gray16>>8) & 0xff);
+                  *(dp++) = (png_byte)(gray16 & 0xff);

                }
             }
          }
                }
             }
          }


@@ -2102,10 +2401,10 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                   png_byte red   = png_ptr->gamma_to_1[*(sp++)];
                   png_byte green = png_ptr->gamma_to_1[*(sp++)];
                   png_byte blue  = png_ptr->gamma_to_1[*(sp++)];
                   png_byte red   = png_ptr->gamma_to_1[*(sp++)];
                   png_byte green = png_ptr->gamma_to_1[*(sp++)];
                   png_byte blue  = png_ptr->gamma_to_1[*(sp++)];

-                  if(red != green || red != blue)
+                  if (red != green || red != blue)

                      rgb_error |= 1;
                   *(dp++) =  png_ptr->gamma_from_1
                      rgb_error |= 1;
                   *(dp++) =  png_ptr->gamma_from_1

-                             [(rc*red + gc*green + bc*blue)>>8];
+                             [(rc*red + gc*green + bc*blue)>>15];

                   *(dp++) = *(sp++);  /* alpha */
                }
             }
                   *(dp++) = *(sp++);  /* alpha */
                }
             }


@@ -2119,9 +2418,9 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                   png_byte red   = *(sp++);
                   png_byte green = *(sp++);
                   png_byte blue  = *(sp++);
                   png_byte red   = *(sp++);
                   png_byte green = *(sp++);
                   png_byte blue  = *(sp++);

-                  if(red != green || red != blue)
+                  if (red != green || red != blue)

                      rgb_error |= 1;
                      rgb_error |= 1;

-                  *(dp++) =  (gc*red + gc*green + bc*blue)>>8;
+                  *(dp++) =  (png_byte)((rc*red + gc*green + bc*blue)>>15);

                   *(dp++) = *(sp++);  /* alpha */
                }
             }
                   *(dp++) = *(sp++);  /* alpha */
                }
             }


@@ -2138,29 +2437,30 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                {
                   png_uint_16 red, green, blue, w;
 
                {
                   png_uint_16 red, green, blue, w;
 

-                  red   = ((*(sp))<<8) | *(sp+1); sp+=2;
-                  green = ((*(sp))<<8) | *(sp+1); sp+=2;
-                  blue  = ((*(sp))<<8) | *(sp+1); sp+=2;
+                  red   = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  blue  = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;

 
 

-                  if(red == green && red == blue)
+                  if (red == green && red == blue)

                      w = red;
                   else
                   {
                      png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red&0xff) >>
                      w = red;
                   else
                   {
                      png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red&0xff) >>

-                                  png_ptr->gamma_shift][red>>8];
-                     png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >>
-                                  png_ptr->gamma_shift][green>>8];
-                     png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff) >> 
-                                  png_ptr->gamma_shift][blue>>8];
-                     png_uint_16 gray16  =  (rc * red_1 + gc * green_1
-                                  + bc * blue_1)>>8;
+                         png_ptr->gamma_shift][red>>8];
+                     png_uint_16 green_1 =
+                         png_ptr->gamma_16_to_1[(green&0xff) >>
+                         png_ptr->gamma_shift][green>>8];
+                     png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff) >>
+                         png_ptr->gamma_shift][blue>>8];
+                     png_uint_16 gray16  = (png_uint_16)((rc * red_1
+                         + gc * green_1 + bc * blue_1)>>15);

                      w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
                          png_ptr->gamma_shift][gray16 >> 8];
                      rgb_error |= 1;
                   }
                      w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
                          png_ptr->gamma_shift][gray16 >> 8];
                      rgb_error |= 1;
                   }

-                  
-                  *(dp++) = (w>>8) & 0xff;
-                  *(dp++) = w & 0xff;
+
+                  *(dp++) = (png_byte)((w>>8) & 0xff);
+                  *(dp++) = (png_byte)(w & 0xff);

                   *(dp++) = *(sp++);  /* alpha */
                   *(dp++) = *(sp++);
                }
                   *(dp++) = *(sp++);  /* alpha */
                   *(dp++) = *(sp++);
                }


@@ -2173,14 +2473,14 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                for (i = 0; i < row_width; i++)
                {
                   png_uint_16 red, green, blue, gray16;
                for (i = 0; i < row_width; i++)
                {
                   png_uint_16 red, green, blue, gray16;

-                  red   = (*(sp)<<8) | *(sp+1); sp+=2;
-                  green = (*(sp)<<8) | *(sp+1); sp+=2;
-                  blue  = (*(sp)<<8) | *(sp+1); sp+=2;
-                  if(red != green || red != blue)
+                  red   = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
+                  green = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
+                  blue  = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
+                  if (red != green || red != blue)

                      rgb_error |= 1;
                      rgb_error |= 1;

-                  gray16  =  (rc * red + gc * green + bc * blue)>>8;
-                  *(dp++) = (gray16>>8) & 0xff;
-                  *(dp++) = gray16 & 0xff;
+                  gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
+                  *(dp++) = (png_byte)((gray16>>8) & 0xff);
+                  *(dp++) = (png_byte)(gray16 & 0xff);

                   *(dp++) = *(sp++);  /* alpha */
                   *(dp++) = *(sp++);
                }
                   *(dp++) = *(sp++);  /* alpha */
                   *(dp++) = *(sp++);
                }


@@ -2191,8 +2491,7 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
       row_info->color_type &= ~PNG_COLOR_MASK_COLOR;
       row_info->pixel_depth = (png_byte)(row_info->channels *
          row_info->bit_depth);
       row_info->color_type &= ~PNG_COLOR_MASK_COLOR;
       row_info->pixel_depth = (png_byte)(row_info->channels *
          row_info->bit_depth);

-      row_info->rowbytes = ((row_width *
-         row_info->pixel_depth + 7) >> 3);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);

    }
    return rgb_error;
 }
    }
    return rgb_error;
 }


@@ -2203,7 +2502,7 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
  * paletted.  Most useful for gamma correction and simplification
  * of code.
  */
  * paletted.  Most useful for gamma correction and simplification
  * of code.
  */

-void
+void PNGAPI

 png_build_grayscale_palette(int bit_depth, png_colorp palette)
 {
    int num_palette;
 png_build_grayscale_palette(int bit_depth, png_colorp palette)
 {
    int num_palette;


@@ -2211,7 +2510,8 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette)
    int i;
    int v;
 
    int i;
    int v;
 

-   png_debug(1, "in png_do_build_grayscale_palette\n");
+   png_debug(1, "in png_do_build_grayscale_palette");
+

    if (palette == NULL)
       return;
 
    if (palette == NULL)
       return;
 


@@ -2221,18 +2521,22 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette)
          num_palette = 2;
          color_inc = 0xff;
          break;
          num_palette = 2;
          color_inc = 0xff;
          break;

+

       case 2:
          num_palette = 4;
          color_inc = 0x55;
          break;
       case 2:
          num_palette = 4;
          color_inc = 0x55;
          break;

+

       case 4:
          num_palette = 16;
          color_inc = 0x11;
          break;
       case 4:
          num_palette = 16;
          color_inc = 0x11;
          break;

+

       case 8:
          num_palette = 256;
          color_inc = 1;
          break;
       case 8:
          num_palette = 256;
          color_inc = 1;
          break;

+

       default:
          num_palette = 0;
          color_inc = 0;
       default:
          num_palette = 0;
          color_inc = 0;


@@ -2247,212 +2551,33 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette)
    }
 }
 
    }
 }
 

-/* This function is currently unused.  Do we really need it? */
-#if defined(PNG_READ_DITHER_SUPPORTED) && defined(PNG_CORRECT_PALETTE_SUPPORTED)
-void
-png_correct_palette(png_structp png_ptr, png_colorp palette,
-   int num_palette)
-{
-   png_debug(1, "in png_correct_palette\n");
-#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
-   if (png_ptr->transformations & (PNG_GAMMA | PNG_BACKGROUND))
-   {
-      png_color back, back_1;
-
-      if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
-      {
-         back.red = png_ptr->gamma_table[png_ptr->background.red];
-         back.green = png_ptr->gamma_table[png_ptr->background.green];
-         back.blue = png_ptr->gamma_table[png_ptr->background.blue];
-
-         back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
-         back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
-         back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
-      }
-      else
-      {
-         double g;
-
-         g = 1.0 / (png_ptr->background_gamma * png_ptr->screen_gamma);
-
-         if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_SCREEN ||
-             fabs(g - 1.0) < PNG_GAMMA_THRESHOLD)
-         {
-            back.red = png_ptr->background.red;
-            back.green = png_ptr->background.green;
-            back.blue = png_ptr->background.blue;
-         }
-         else
-         {
-            back.red =
-               (png_byte)(pow((double)png_ptr->background.red/255, g) *
-                255.0 + 0.5);
-            back.green =
-               (png_byte)(pow((double)png_ptr->background.green/255, g) *
-                255.0 + 0.5);
-            back.blue =
-               (png_byte)(pow((double)png_ptr->background.blue/255, g) *
-                255.0 + 0.5);
-         }
-
-         g = 1.0 / png_ptr->background_gamma;
-
-         back_1.red =
-            (png_byte)(pow((double)png_ptr->background.red/255, g) *
-             255.0 + 0.5);
-         back_1.green =
-            (png_byte)(pow((double)png_ptr->background.green/255, g) *
-             255.0 + 0.5);
-         back_1.blue =
-            (png_byte)(pow((double)png_ptr->background.blue/255, g) *
-             255.0 + 0.5);
-      }
-
-      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         png_uint_32 i;
-
-         for (i = 0; i < (png_uint_32)num_palette; i++)
-         {
-            if (i < png_ptr->num_trans && png_ptr->trans[i] == 0)
-            {
-               palette[i] = back;
-            }
-            else if (i < png_ptr->num_trans && png_ptr->trans[i] != 0xff)
-            {
-               png_byte v, w;
-
-               v = png_ptr->gamma_to_1[png_ptr->palette[i].red];
-               png_composite(w, v, png_ptr->trans[i], back_1.red);
-               palette[i].red = png_ptr->gamma_from_1[w];
-
-               v = png_ptr->gamma_to_1[png_ptr->palette[i].green];
-               png_composite(w, v, png_ptr->trans[i], back_1.green);
-               palette[i].green = png_ptr->gamma_from_1[w];
-
-               v = png_ptr->gamma_to_1[png_ptr->palette[i].blue];
-               png_composite(w, v, png_ptr->trans[i], back_1.blue);
-               palette[i].blue = png_ptr->gamma_from_1[w];
-            }
-            else
-            {
-               palette[i].red = png_ptr->gamma_table[palette[i].red];
-               palette[i].green = png_ptr->gamma_table[palette[i].green];
-               palette[i].blue = png_ptr->gamma_table[palette[i].blue];
-            }
-         }
-      }
-      else
-      {
-         int i;
-
-         for (i = 0; i < num_palette; i++)
-         {
-            if (palette[i].red == (png_byte)png_ptr->trans_values.gray)
-            {
-               palette[i] = back;
-            }
-            else
-            {
-               palette[i].red = png_ptr->gamma_table[palette[i].red];
-               palette[i].green = png_ptr->gamma_table[palette[i].green];
-               palette[i].blue = png_ptr->gamma_table[palette[i].blue];
-            }
-         }
-      }
-   }
-   else
-#endif
-#if defined(PNG_READ_GAMMA_SUPPORTED)
-   if (png_ptr->transformations & PNG_GAMMA)
-   {
-      int i;
-
-      for (i = 0; i < num_palette; i++)
-      {
-         palette[i].red = png_ptr->gamma_table[palette[i].red];
-         palette[i].green = png_ptr->gamma_table[palette[i].green];
-         palette[i].blue = png_ptr->gamma_table[palette[i].blue];
-      }
-   }
-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
-   else
-#endif
-#endif
-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
-   if (png_ptr->transformations & PNG_BACKGROUND)
-   {
-      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
-      {
-         png_color back;
-
-         back.red   = (png_byte)png_ptr->background.red;
-         back.green = (png_byte)png_ptr->background.green;
-         back.blue  = (png_byte)png_ptr->background.blue;
-
-         for (i = 0; i < (int)png_ptr->num_trans; i++)
-         {
-            if (png_ptr->trans[i] == 0)
-            {
-               palette[i].red = back.red;
-               palette[i].green = back.green;
-               palette[i].blue = back.blue;
-            }
-            else if (png_ptr->trans[i] != 0xff)
-            {
-               png_composite(palette[i].red, png_ptr->palette[i].red,
-                  png_ptr->trans[i], back.red);
-               png_composite(palette[i].green, png_ptr->palette[i].green,
-                  png_ptr->trans[i], back.green);
-               png_composite(palette[i].blue, png_ptr->palette[i].blue,
-                  png_ptr->trans[i], back.blue);
-            }
-         }
-      }
-      else /* assume grayscale palette (what else could it be?) */
-      {
-         int i;
-
-         for (i = 0; i < num_palette; i++)
-         {
-            if (i == (png_byte)png_ptr->trans_values.gray)
-            {
-               palette[i].red = (png_byte)png_ptr->background.red;
-               palette[i].green = (png_byte)png_ptr->background.green;
-               palette[i].blue = (png_byte)png_ptr->background.blue;
-            }
-         }
-      }
-   }
-#endif
-}
-#endif

 
 

-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+#ifdef PNG_READ_BACKGROUND_SUPPORTED

 /* Replace any alpha or transparency with the supplied background color.
  * "background" is already in the screen gamma, while "background_1" is
  * at a gamma of 1.0.  Paletted files have already been taken care of.
  */
 /* Replace any alpha or transparency with the supplied background color.
  * "background" is already in the screen gamma, while "background_1" is
  * at a gamma of 1.0.  Paletted files have already been taken care of.
  */

-void
+void /* PRIVATE */

 png_do_background(png_row_infop row_info, png_bytep row,
 png_do_background(png_row_infop row_info, png_bytep row,

-   png_color_16p trans_values, png_color_16p background,
-   png_color_16p background_1,
+   png_color_16p trans_color, png_color_16p background
+#ifdef PNG_READ_GAMMA_SUPPORTED
+   , png_color_16p background_1,

    png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1,
    png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1,
    png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1,
    png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1,

-   png_uint_16pp gamma_16_to_1, int gamma_shift)
+   png_uint_16pp gamma_16_to_1, int gamma_shift
+#endif
+   )

 {
    png_bytep sp, dp;
    png_uint_32 i;
    png_uint_32 row_width=row_info->width;
    int shift;
 
 {
    png_bytep sp, dp;
    png_uint_32 i;
    png_uint_32 row_width=row_info->width;
    int shift;
 

-   png_debug(1, "in png_do_background\n");
+   png_debug(1, "in png_do_background");
+

    if (background != NULL &&
    if (background != NULL &&

-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-       row != NULL && row_info != NULL &&
-#endif

       (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) ||
       (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) ||

-      (row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_values)))
+      (row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_color)))

    {
       switch (row_info->color_type)
       {
    {
       switch (row_info->color_type)
       {


@@ -2466,8 +2591,8 @@ png_do_background(png_row_infop row_info, png_bytep row,
                   shift = 7;
                   for (i = 0; i < row_width; i++)
                   {
                   shift = 7;
                   for (i = 0; i < row_width; i++)
                   {

-                     if ((png_uint_16)((*sp >> shift) & 0x1)
-                        == trans_values->gray)
+                     if ((png_uint_16)((*sp >> shift) & 0x01)
+                        == trans_color->gray)

                      {
                         *sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
                         *sp |= (png_byte)(background->gray << shift);
                      {
                         *sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
                         *sp |= (png_byte)(background->gray << shift);


@@ -2482,26 +2607,27 @@ png_do_background(png_row_infop row_info, png_bytep row,
                   }
                   break;
                }
                   }
                   break;
                }

+

                case 2:
                {
                case 2:
                {

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

                   if (gamma_table != NULL)
                   {
                      sp = row;
                      shift = 6;
                      for (i = 0; i < row_width; i++)
                      {
                   if (gamma_table != NULL)
                   {
                      sp = row;
                      shift = 6;
                      for (i = 0; i < row_width; i++)
                      {

-                        if ((png_uint_16)((*sp >> shift) & 0x3)
-                            == trans_values->gray)
+                        if ((png_uint_16)((*sp >> shift) & 0x03)
+                            == trans_color->gray)

                         {
                            *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
                            *sp |= (png_byte)(background->gray << shift);
                         }
                         else
                         {
                         {
                            *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
                            *sp |= (png_byte)(background->gray << shift);
                         }
                         else
                         {

-                           png_byte p = (*sp >> shift) & 0x3;
-                           png_byte g = (gamma_table [p | (p << 2) | (p << 4) |
-                               (p << 6)] >> 6) & 0x3;
+                           png_byte p = (png_byte)((*sp >> shift) & 0x03);
+                           png_byte g = (png_byte)((gamma_table [p | (p << 2) |
+                               (p << 4) | (p << 6)] >> 6) & 0x03);

                            *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
                            *sp |= (png_byte)(g << shift);
                         }
                            *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
                            *sp |= (png_byte)(g << shift);
                         }


@@ -2521,8 +2647,8 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      shift = 6;
                      for (i = 0; i < row_width; i++)
                      {
                      shift = 6;
                      for (i = 0; i < row_width; i++)
                      {

-                        if ((png_uint_16)((*sp >> shift) & 0x3)
-                            == trans_values->gray)
+                        if ((png_uint_16)((*sp >> shift) & 0x03)
+                            == trans_color->gray)

                         {
                            *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
                            *sp |= (png_byte)(background->gray << shift);
                         {
                            *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
                            *sp |= (png_byte)(background->gray << shift);


@@ -2538,25 +2664,27 @@ png_do_background(png_row_infop row_info, png_bytep row,
                   }
                   break;
                }
                   }
                   break;
                }

+

                case 4:
                {
                case 4:
                {

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

                   if (gamma_table != NULL)
                   {
                      sp = row;
                      shift = 4;
                      for (i = 0; i < row_width; i++)
                      {
                   if (gamma_table != NULL)
                   {
                      sp = row;
                      shift = 4;
                      for (i = 0; i < row_width; i++)
                      {

-                        if ((png_uint_16)((*sp >> shift) & 0xf)
-                            == trans_values->gray)
+                        if ((png_uint_16)((*sp >> shift) & 0x0f)
+                            == trans_color->gray)

                         {
                            *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
                            *sp |= (png_byte)(background->gray << shift);
                         }
                         else
                         {
                         {
                            *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
                            *sp |= (png_byte)(background->gray << shift);
                         }
                         else
                         {

-                           png_byte p = (*sp >> shift) & 0xf;
-                           png_byte g = (gamma_table[p | (p << 4)] >> 4) & 0xf;
+                           png_byte p = (png_byte)((*sp >> shift) & 0x0f);
+                           png_byte g = (png_byte)((gamma_table[p |
+                             (p << 4)] >> 4) & 0x0f);

                            *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
                            *sp |= (png_byte)(g << shift);
                         }
                            *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
                            *sp |= (png_byte)(g << shift);
                         }


@@ -2576,8 +2704,8 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      shift = 4;
                      for (i = 0; i < row_width; i++)
                      {
                      shift = 4;
                      for (i = 0; i < row_width; i++)
                      {

-                        if ((png_uint_16)((*sp >> shift) & 0xf)
-                            == trans_values->gray)
+                        if ((png_uint_16)((*sp >> shift) & 0x0f)
+                            == trans_color->gray)

                         {
                            *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
                            *sp |= (png_byte)(background->gray << shift);
                         {
                            *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
                            *sp |= (png_byte)(background->gray << shift);


@@ -2593,15 +2721,16 @@ png_do_background(png_row_infop row_info, png_bytep row,
                   }
                   break;
                }
                   }
                   break;
                }

+

                case 8:
                {
                case 8:
                {

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

                   if (gamma_table != NULL)
                   {
                      sp = row;
                      for (i = 0; i < row_width; i++, sp++)
                      {
                   if (gamma_table != NULL)
                   {
                      sp = row;
                      for (i = 0; i < row_width; i++, sp++)
                      {

-                        if (*sp == trans_values->gray)
+                        if (*sp == trans_color->gray)

                         {
                            *sp = (png_byte)background->gray;
                         }
                         {
                            *sp = (png_byte)background->gray;
                         }


@@ -2617,7 +2746,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      sp = row;
                      for (i = 0; i < row_width; i++, sp++)
                      {
                      sp = row;
                      for (i = 0; i < row_width; i++, sp++)
                      {

-                        if (*sp == trans_values->gray)
+                        if (*sp == trans_color->gray)

                         {
                            *sp = (png_byte)background->gray;
                         }
                         {
                            *sp = (png_byte)background->gray;
                         }


@@ -2625,9 +2754,10 @@ png_do_background(png_row_infop row_info, png_bytep row,
                   }
                   break;
                }
                   }
                   break;
                }

+

                case 16:
                {
                case 16:
                {

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

                   if (gamma_16 != NULL)
                   {
                      sp = row;
                   if (gamma_16 != NULL)
                   {
                      sp = row;


@@ -2635,10 +2765,10 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      {
                         png_uint_16 v;
 
                      {
                         png_uint_16 v;
 

-                        v = ((png_uint_16)(*sp) << 8) + *(sp + 1);
-                        if (v == trans_values->gray)
+                        v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                        if (v == trans_color->gray)

                         {
                         {

-                           /* background is already in screen gamma */
+                           /* Background is already in screen gamma */

                            *sp = (png_byte)((background->gray >> 8) & 0xff);
                            *(sp + 1) = (png_byte)(background->gray & 0xff);
                         }
                            *sp = (png_byte)((background->gray >> 8) & 0xff);
                            *(sp + 1) = (png_byte)(background->gray & 0xff);
                         }


@@ -2658,8 +2788,8 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      {
                         png_uint_16 v;
 
                      {
                         png_uint_16 v;
 

-                        v = ((png_uint_16)(*sp) << 8) + *(sp + 1);
-                        if (v == trans_values->gray)
+                        v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                        if (v == trans_color->gray)

                         {
                            *sp = (png_byte)((background->gray >> 8) & 0xff);
                            *(sp + 1) = (png_byte)(background->gray & 0xff);
                         {
                            *sp = (png_byte)((background->gray >> 8) & 0xff);
                            *(sp + 1) = (png_byte)(background->gray & 0xff);


@@ -2671,19 +2801,20 @@ png_do_background(png_row_infop row_info, png_bytep row,
             }
             break;
          }
             }
             break;
          }

+

          case PNG_COLOR_TYPE_RGB:
          {
             if (row_info->bit_depth == 8)
             {
          case PNG_COLOR_TYPE_RGB:
          {
             if (row_info->bit_depth == 8)
             {

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

                if (gamma_table != NULL)
                {
                   sp = row;
                   for (i = 0; i < row_width; i++, sp += 3)
                   {
                if (gamma_table != NULL)
                {
                   sp = row;
                   for (i = 0; i < row_width; i++, sp += 3)
                   {

-                     if (*sp == trans_values->red &&
-                        *(sp + 1) == trans_values->green &&
-                        *(sp + 2) == trans_values->blue)
+                     if (*sp == trans_color->red &&
+                        *(sp + 1) == trans_color->green &&
+                        *(sp + 2) == trans_color->blue)

                      {
                         *sp = (png_byte)background->red;
                         *(sp + 1) = (png_byte)background->green;
                      {
                         *sp = (png_byte)background->red;
                         *(sp + 1) = (png_byte)background->green;


@@ -2703,9 +2834,9 @@ png_do_background(png_row_infop row_info, png_bytep row,
                   sp = row;
                   for (i = 0; i < row_width; i++, sp += 3)
                   {
                   sp = row;
                   for (i = 0; i < row_width; i++, sp += 3)
                   {

-                     if (*sp == trans_values->red &&
-                        *(sp + 1) == trans_values->green &&
-                        *(sp + 2) == trans_values->blue)
+                     if (*sp == trans_color->red &&
+                        *(sp + 1) == trans_color->green &&
+                        *(sp + 2) == trans_color->blue)

                      {
                         *sp = (png_byte)background->red;
                         *(sp + 1) = (png_byte)background->green;
                      {
                         *sp = (png_byte)background->red;
                         *(sp + 1) = (png_byte)background->green;


@@ -2716,19 +2847,19 @@ png_do_background(png_row_infop row_info, png_bytep row,
             }
             else /* if (row_info->bit_depth == 16) */
             {
             }
             else /* if (row_info->bit_depth == 16) */
             {

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

                if (gamma_16 != NULL)
                {
                   sp = row;
                   for (i = 0; i < row_width; i++, sp += 6)
                   {
                if (gamma_16 != NULL)
                {
                   sp = row;
                   for (i = 0; i < row_width; i++, sp += 6)
                   {

-                     png_uint_16 r = ((png_uint_16)(*sp) << 8) + *(sp + 1);
-                     png_uint_16 g = ((png_uint_16)(*(sp + 2)) << 8) + *(sp + 3);
-                     png_uint_16 b = ((png_uint_16)(*(sp + 4)) << 8) + *(sp + 5);
-                     if (r == trans_values->red && g == trans_values->green &&
-                        b == trans_values->blue)
+                     png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                     png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
+                     png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5));
+                     if (r == trans_color->red && g == trans_color->green &&
+                        b == trans_color->blue)

                      {
                      {

-                        /* background is already in screen gamma */
+                        /* Background is already in screen gamma */

                         *sp = (png_byte)((background->red >> 8) & 0xff);
                         *(sp + 1) = (png_byte)(background->red & 0xff);
                         *(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
                         *sp = (png_byte)((background->red >> 8) & 0xff);
                         *(sp + 1) = (png_byte)(background->red & 0xff);
                         *(sp + 2) = (png_byte)((background->green >> 8) & 0xff);


@@ -2756,12 +2887,12 @@ png_do_background(png_row_infop row_info, png_bytep row,
                   sp = row;
                   for (i = 0; i < row_width; i++, sp += 6)
                   {
                   sp = row;
                   for (i = 0; i < row_width; i++, sp += 6)
                   {

-                     png_uint_16 r = ((png_uint_16)(*sp) << 8) + *(sp + 1);
-                     png_uint_16 g = ((png_uint_16)(*(sp + 2)) << 8) + *(sp + 3);
-                     png_uint_16 b = ((png_uint_16)(*(sp + 4)) << 8) + *(sp + 5);
+                     png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp+1));
+                     png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
+                     png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5));

 
 

-                     if (r == trans_values->red && g == trans_values->green &&
-                        b == trans_values->blue)
+                     if (r == trans_color->red && g == trans_color->green &&
+                        b == trans_color->blue)

                      {
                         *sp = (png_byte)((background->red >> 8) & 0xff);
                         *(sp + 1) = (png_byte)(background->red & 0xff);
                      {
                         *sp = (png_byte)((background->red >> 8) & 0xff);
                         *(sp + 1) = (png_byte)(background->red & 0xff);


@@ -2775,11 +2906,12 @@ png_do_background(png_row_infop row_info, png_bytep row,
             }
             break;
          }
             }
             break;
          }

+

          case PNG_COLOR_TYPE_GRAY_ALPHA:
          {
             if (row_info->bit_depth == 8)
             {
          case PNG_COLOR_TYPE_GRAY_ALPHA:
          {
             if (row_info->bit_depth == 8)
             {

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

                if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
                    gamma_table != NULL)
                {
                if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
                    gamma_table != NULL)
                {


@@ -2795,7 +2927,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      }
                      else if (a == 0)
                      {
                      }
                      else if (a == 0)
                      {

-                        /* background is already in screen gamma */
+                        /* Background is already in screen gamma */

                         *dp = (png_byte)background->gray;
                      }
                      else
                         *dp = (png_byte)background->gray;
                      }
                      else


@@ -2821,6 +2953,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      {
                         *dp = *sp;
                      }
                      {
                         *dp = *sp;
                      }

+#ifdef PNG_READ_GAMMA_SUPPORTED

                      else if (a == 0)
                      {
                         *dp = (png_byte)background->gray;
                      else if (a == 0)
                      {
                         *dp = (png_byte)background->gray;


@@ -2829,12 +2962,15 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      {
                         png_composite(*dp, *sp, a, background_1->gray);
                      }
                      {
                         png_composite(*dp, *sp, a, background_1->gray);
                      }

+#else
+                     *dp = (png_byte)background->gray;
+#endif

                   }
                }
             }
             else /* if (png_ptr->bit_depth == 16) */
             {
                   }
                }
             }
             else /* if (png_ptr->bit_depth == 16) */
             {

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

                if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
                    gamma_16_to_1 != NULL)
                {
                if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
                    gamma_16_to_1 != NULL)
                {


@@ -2842,7 +2978,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                   dp = row;
                   for (i = 0; i < row_width; i++, sp += 4, dp += 2)
                   {
                   dp = row;
                   for (i = 0; i < row_width; i++, sp += 4, dp += 2)
                   {

-                     png_uint_16 a = ((png_uint_16)(*(sp + 2)) << 8) + *(sp + 3);
+                     png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));

 
                      if (a == (png_uint_16)0xffff)
                      {
 
                      if (a == (png_uint_16)0xffff)
                      {


@@ -2852,12 +2988,17 @@ png_do_background(png_row_infop row_info, png_bytep row,
                         *dp = (png_byte)((v >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(v & 0xff);
                      }
                         *dp = (png_byte)((v >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(v & 0xff);
                      }

+#ifdef PNG_READ_GAMMA_SUPPORTED

                      else if (a == 0)
                      else if (a == 0)

+#else
+                     else
+#endif

                      {
                      {

-                        /* background is already in screen gamma */
+                        /* Background is already in screen gamma */

                         *dp = (png_byte)((background->gray >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(background->gray & 0xff);
                      }
                         *dp = (png_byte)((background->gray >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(background->gray & 0xff);
                      }

+#ifdef PNG_READ_GAMMA_SUPPORTED

                      else
                      {
                         png_uint_16 g, v, w;
                      else
                      {
                         png_uint_16 g, v, w;


@@ -2868,6 +3009,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                         *dp = (png_byte)((w >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(w & 0xff);
                      }
                         *dp = (png_byte)((w >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(w & 0xff);
                      }

+#endif

                   }
                }
                else
                   }
                }
                else


@@ -2877,35 +3019,42 @@ png_do_background(png_row_infop row_info, png_bytep row,
                   dp = row;
                   for (i = 0; i < row_width; i++, sp += 4, dp += 2)
                   {
                   dp = row;
                   for (i = 0; i < row_width; i++, sp += 4, dp += 2)
                   {

-                     png_uint_16 a = ((png_uint_16)(*(sp + 2)) << 8) + *(sp + 3);
+                     png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));

                      if (a == (png_uint_16)0xffff)
                      {
                         png_memcpy(dp, sp, 2);
                      }
                      if (a == (png_uint_16)0xffff)
                      {
                         png_memcpy(dp, sp, 2);
                      }

+#ifdef PNG_READ_GAMMA_SUPPORTED

                      else if (a == 0)
                      else if (a == 0)

+#else
+                     else
+#endif

                      {
                         *dp = (png_byte)((background->gray >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(background->gray & 0xff);
                      }
                      {
                         *dp = (png_byte)((background->gray >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(background->gray & 0xff);
                      }

+#ifdef PNG_READ_GAMMA_SUPPORTED

                      else
                      {
                         png_uint_16 g, v;
 
                      else
                      {
                         png_uint_16 g, v;
 

-                        g = ((png_uint_16)(*sp) << 8) + *(sp + 1);
+                        g = (png_uint_16)(((*sp) << 8) + *(sp + 1));

                         png_composite_16(v, g, a, background_1->gray);
                         *dp = (png_byte)((v >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(v & 0xff);
                      }
                         png_composite_16(v, g, a, background_1->gray);
                         *dp = (png_byte)((v >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(v & 0xff);
                      }

+#endif

                   }
                }
             }
             break;
          }
                   }
                }
             }
             break;
          }

+

          case PNG_COLOR_TYPE_RGB_ALPHA:
          {
             if (row_info->bit_depth == 8)
             {
          case PNG_COLOR_TYPE_RGB_ALPHA:
          {
             if (row_info->bit_depth == 8)
             {

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

                if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
                    gamma_table != NULL)
                {
                if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
                    gamma_table != NULL)
                {


@@ -2923,7 +3072,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      }
                      else if (a == 0)
                      {
                      }
                      else if (a == 0)
                      {

-                        /* background is already in screen gamma */
+                        /* Background is already in screen gamma */

                         *dp = (png_byte)background->red;
                         *(dp + 1) = (png_byte)background->green;
                         *(dp + 2) = (png_byte)background->blue;
                         *dp = (png_byte)background->red;
                         *(dp + 1) = (png_byte)background->green;
                         *(dp + 2) = (png_byte)background->blue;


@@ -2978,7 +3127,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
             }
             else /* if (row_info->bit_depth == 16) */
             {
             }
             else /* if (row_info->bit_depth == 16) */
             {

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

                if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
                    gamma_16_to_1 != NULL)
                {
                if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
                    gamma_16_to_1 != NULL)
                {


@@ -3004,7 +3153,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      }
                      else if (a == 0)
                      {
                      }
                      else if (a == 0)
                      {

-                        /* background is already in screen gamma */
+                        /* Background is already in screen gamma */

                         *dp = (png_byte)((background->red >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(background->red & 0xff);
                         *(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
                         *dp = (png_byte)((background->red >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(background->red & 0xff);
                         *(dp + 2) = (png_byte)((background->green >> 8) & 0xff);


@@ -3017,17 +3166,17 @@ png_do_background(png_row_infop row_info, png_bytep row,
                         png_uint_16 v, w, x;
 
                         v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
                         png_uint_16 v, w, x;
 
                         v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];

-                        png_composite_16(w, v, a, background->red);
+                        png_composite_16(w, v, a, background_1->red);

                         x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
                         *dp = (png_byte)((x >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(x & 0xff);
                         v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
                         x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
                         *dp = (png_byte)((x >> 8) & 0xff);
                         *(dp + 1) = (png_byte)(x & 0xff);
                         v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];

-                        png_composite_16(w, v, a, background->green);
+                        png_composite_16(w, v, a, background_1->green);

                         x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
                         *(dp + 2) = (png_byte)((x >> 8) & 0xff);
                         *(dp + 3) = (png_byte)(x & 0xff);
                         v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
                         x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
                         *(dp + 2) = (png_byte)((x >> 8) & 0xff);
                         *(dp + 3) = (png_byte)(x & 0xff);
                         v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];

-                        png_composite_16(w, v, a, background->blue);
+                        png_composite_16(w, v, a, background_1->blue);

                         x = gamma_16_from_1[(w & 0xff) >> gamma_shift][w >> 8];
                         *(dp + 4) = (png_byte)((x >> 8) & 0xff);
                         *(dp + 5) = (png_byte)(x & 0xff);
                         x = gamma_16_from_1[(w & 0xff) >> gamma_shift][w >> 8];
                         *(dp + 4) = (png_byte)((x >> 8) & 0xff);
                         *(dp + 5) = (png_byte)(x & 0xff);


@@ -3060,11 +3209,11 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      {
                         png_uint_16 v;
 
                      {
                         png_uint_16 v;
 

-                        png_uint_16 r = ((png_uint_16)(*sp) << 8) + *(sp + 1);
-                        png_uint_16 g = ((png_uint_16)(*(sp + 2)) << 8)
-                            + *(sp + 3);
-                        png_uint_16 b = ((png_uint_16)(*(sp + 4)) << 8)
-                            + *(sp + 5);
+                        png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                        png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+                            + *(sp + 3));
+                        png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+                            + *(sp + 5));

 
                         png_composite_16(v, r, a, background->red);
                         *dp = (png_byte)((v >> 8) & 0xff);
 
                         png_composite_16(v, r, a, background->red);
                         *dp = (png_byte)((v >> 8) & 0xff);


@@ -3089,21 +3238,20 @@ png_do_background(png_row_infop row_info, png_bytep row,
          row_info->channels--;
          row_info->pixel_depth = (png_byte)(row_info->channels *
             row_info->bit_depth);
          row_info->channels--;
          row_info->pixel_depth = (png_byte)(row_info->channels *
             row_info->bit_depth);

-         row_info->rowbytes = ((row_width *
-            row_info->pixel_depth + 7) >> 3);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);

       }
    }
 }
 #endif
 
       }
    }
 }
 #endif
 

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

 /* Gamma correct the image, avoiding the alpha channel.  Make sure
  * you do this after you deal with the transparency issue on grayscale
 /* Gamma correct the image, avoiding the alpha channel.  Make sure
  * you do this after you deal with the transparency issue on grayscale

- * or rgb images. If your bit depth is 8, use gamma_table, if it
+ * or RGB images. If your bit depth is 8, use gamma_table, if it

  * is 16, use gamma_16_table and gamma_shift.  Build these with
  * build_gamma_table().
  */
  * is 16, use gamma_16_table and gamma_shift.  Build these with
  * build_gamma_table().
  */

-void
+void /* PRIVATE */

 png_do_gamma(png_row_infop row_info, png_bytep row,
    png_bytep gamma_table, png_uint_16pp gamma_16_table,
    int gamma_shift)
 png_do_gamma(png_row_infop row_info, png_bytep row,
    png_bytep gamma_table, png_uint_16pp gamma_16_table,
    int gamma_shift)


@@ -3112,11 +3260,9 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
    png_uint_32 i;
    png_uint_32 row_width=row_info->width;
 
    png_uint_32 i;
    png_uint_32 row_width=row_info->width;
 

-   png_debug(1, "in png_do_gamma\n");
+   png_debug(1, "in png_do_gamma");
+

    if (
    if (

-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-       row != NULL && row_info != NULL &&
-#endif

        ((row_info->bit_depth <= 8 && gamma_table != NULL) ||
         (row_info->bit_depth == 16 && gamma_16_table != NULL)))
    {
        ((row_info->bit_depth <= 8 && gamma_table != NULL) ||
         (row_info->bit_depth == 16 && gamma_16_table != NULL)))
    {


@@ -3160,6 +3306,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
             }
             break;
          }
             }
             break;
          }

+

          case PNG_COLOR_TYPE_RGB_ALPHA:
          {
             if (row_info->bit_depth == 8)
          case PNG_COLOR_TYPE_RGB_ALPHA:
          {
             if (row_info->bit_depth == 8)


@@ -3197,6 +3344,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
             }
             break;
          }
             }
             break;
          }

+

          case PNG_COLOR_TYPE_GRAY_ALPHA:
          {
             if (row_info->bit_depth == 8)
          case PNG_COLOR_TYPE_GRAY_ALPHA:
          {
             if (row_info->bit_depth == 8)


@@ -3221,6 +3369,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
             }
             break;
          }
             }
             break;
          }

+

          case PNG_COLOR_TYPE_GRAY:
          {
             if (row_info->bit_depth == 2)
          case PNG_COLOR_TYPE_GRAY:
          {
             if (row_info->bit_depth == 2)


@@ -3233,13 +3382,15 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
                   int c = *sp & 0x0c;
                   int d = *sp & 0x03;
 
                   int c = *sp & 0x0c;
                   int d = *sp & 0x03;
 

-                  *sp = ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)])   ) & 0xc0)|
-                        ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
-                        ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
-                        ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6)       );
+                  *sp = (png_byte)(
+                      ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)])   ) & 0xc0)|
+                      ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
+                      ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
+                      ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));

                   sp++;
                }
             }
                   sp++;
                }
             }

+

             if (row_info->bit_depth == 4)
             {
                sp = row;
             if (row_info->bit_depth == 4)
             {
                sp = row;


@@ -3248,11 +3399,12 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
                   int msb = *sp & 0xf0;
                   int lsb = *sp & 0x0f;
 
                   int msb = *sp & 0xf0;
                   int lsb = *sp & 0x0f;
 

-                  *sp = (((int)gamma_table[msb | (msb >> 4)]) & 0xf0) |
-                        (((int)gamma_table[(lsb << 4) | lsb]) >> 4);
+                  *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
+                      | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));

                   sp++;
                }
             }
                   sp++;
                }
             }

+

             else if (row_info->bit_depth == 8)
             {
                sp = row;
             else if (row_info->bit_depth == 8)
             {
                sp = row;


@@ -3262,6 +3414,7 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
                   sp++;
                }
             }
                   sp++;
                }
             }

+

             else if (row_info->bit_depth == 16)
             {
                sp = row;
             else if (row_info->bit_depth == 16)
             {
                sp = row;


@@ -3280,24 +3433,22 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_EXPAND_SUPPORTED)
-/* Expands a palette row to an rgb or rgba row depending
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* Expands a palette row to an RGB or RGBA row depending

  * upon whether you supply trans and num_trans.
  */
  * upon whether you supply trans and num_trans.
  */

-void
+void /* PRIVATE */

 png_do_expand_palette(png_row_infop row_info, png_bytep row,
 png_do_expand_palette(png_row_infop row_info, png_bytep row,

-   png_colorp palette, png_bytep trans, int num_trans)
+   png_colorp palette, png_bytep trans_alpha, int num_trans)

 {
    int shift, value;
    png_bytep sp, dp;
    png_uint_32 i;
    png_uint_32 row_width=row_info->width;
 
 {
    int shift, value;
    png_bytep sp, dp;
    png_uint_32 i;
    png_uint_32 row_width=row_info->width;
 

-   png_debug(1, "in png_do_expand_palette\n");
+   png_debug(1, "in png_do_expand_palette");
+

    if (
    if (

-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-       row != NULL && row_info != NULL &&
-#endif

        row_info->color_type == PNG_COLOR_TYPE_PALETTE)
    {
       if (row_info->bit_depth < 8)
        row_info->color_type == PNG_COLOR_TYPE_PALETTE)
    {
       if (row_info->bit_depth < 8)


@@ -3308,10 +3459,10 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
             {
                sp = row + (png_size_t)((row_width - 1) >> 3);
                dp = row + (png_size_t)row_width - 1;
             {
                sp = row + (png_size_t)((row_width - 1) >> 3);
                dp = row + (png_size_t)row_width - 1;

-               shift = 7 - (int)((row_width + 7) & 7);
+               shift = 7 - (int)((row_width + 7) & 0x07);

                for (i = 0; i < row_width; i++)
                {
                for (i = 0; i < row_width; i++)
                {

-                  if ((*sp >> shift) & 0x1)
+                  if ((*sp >> shift) & 0x01)

                      *dp = 1;
                   else
                      *dp = 0;
                      *dp = 1;
                   else
                      *dp = 0;


@@ -3327,14 +3478,15 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
                }
                break;
             }
                }
                break;
             }

+

             case 2:
             {
                sp = row + (png_size_t)((row_width - 1) >> 2);
                dp = row + (png_size_t)row_width - 1;
             case 2:
             {
                sp = row + (png_size_t)((row_width - 1) >> 2);
                dp = row + (png_size_t)row_width - 1;

-               shift = (int)((3 - ((row_width + 3) & 3)) << 1);
+               shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);

                for (i = 0; i < row_width; i++)
                {
                for (i = 0; i < row_width; i++)
                {

-                  value = (*sp >> shift) & 0x3;
+                  value = (*sp >> shift) & 0x03;

                   *dp = (png_byte)value;
                   if (shift == 6)
                   {
                   *dp = (png_byte)value;
                   if (shift == 6)
                   {


@@ -3348,14 +3500,15 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
                }
                break;
             }
                }
                break;
             }

+

             case 4:
             {
                sp = row + (png_size_t)((row_width - 1) >> 1);
                dp = row + (png_size_t)row_width - 1;
             case 4:
             {
                sp = row + (png_size_t)((row_width - 1) >> 1);
                dp = row + (png_size_t)row_width - 1;

-               shift = (int)((row_width & 1) << 2);
+               shift = (int)((row_width & 0x01) << 2);

                for (i = 0; i < row_width; i++)
                {
                for (i = 0; i < row_width; i++)
                {

-                  value = (*sp >> shift) & 0xf;
+                  value = (*sp >> shift) & 0x0f;

                   *dp = (png_byte)value;
                   if (shift == 4)
                   {
                   *dp = (png_byte)value;
                   if (shift == 4)
                   {


@@ -3378,7 +3531,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
       {
          case 8:
          {
       {
          case 8:
          {

-            if (trans != NULL)
+            if (trans_alpha != NULL)

             {
                sp = row + (png_size_t)row_width - 1;
                dp = row + (png_size_t)(row_width << 2) - 1;
             {
                sp = row + (png_size_t)row_width - 1;
                dp = row + (png_size_t)(row_width << 2) - 1;


@@ -3388,7 +3541,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
                   if ((int)(*sp) >= num_trans)
                      *dp-- = 0xff;
                   else
                   if ((int)(*sp) >= num_trans)
                      *dp-- = 0xff;
                   else

-                     *dp-- = trans[*sp];
+                     *dp-- = trans_alpha[*sp];

                   *dp-- = palette[*sp].blue;
                   *dp-- = palette[*sp].green;
                   *dp-- = palette[*sp].red;
                   *dp-- = palette[*sp].blue;
                   *dp-- = palette[*sp].green;
                   *dp-- = palette[*sp].red;


@@ -3412,6 +3565,7 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
                   *dp-- = palette[*sp].red;
                   sp--;
                }
                   *dp-- = palette[*sp].red;
                   sp--;
                }

+

                row_info->bit_depth = 8;
                row_info->pixel_depth = 24;
                row_info->rowbytes = row_width * 3;
                row_info->bit_depth = 8;
                row_info->pixel_depth = 24;
                row_info->rowbytes = row_width * 3;


@@ -3424,10 +3578,10 @@ png_do_expand_palette(png_row_infop row_info, png_bytep row,
    }
 }
 
    }
 }
 

-/* If the bit depth < 8, it is expanded to 8.  Also, if the
- * transparency value is supplied, an alpha channel is built.
+/* If the bit depth < 8, it is expanded to 8.  Also, if the already
+ * expanded transparency value is supplied, an alpha channel is built.

  */
  */

-void
+void /* PRIVATE */

 png_do_expand(png_row_infop row_info, png_bytep row,
    png_color_16p trans_value)
 {
 png_do_expand(png_row_infop row_info, png_bytep row,
    png_color_16p trans_value)
 {


@@ -3436,14 +3590,12 @@ png_do_expand(png_row_infop row_info, png_bytep row,
    png_uint_32 i;
    png_uint_32 row_width=row_info->width;
 
    png_uint_32 i;
    png_uint_32 row_width=row_info->width;
 

-   png_debug(1, "in png_do_expand\n");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-   if (row != NULL && row_info != NULL)
-#endif
+   png_debug(1, "in png_do_expand");
+

    {
       if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
       {
    {
       if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
       {

-         png_uint_16 gray = trans_value ? trans_value->gray : 0;
+         png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0);

 
          if (row_info->bit_depth < 8)
          {
 
          if (row_info->bit_depth < 8)
          {


@@ -3451,13 +3603,13 @@ png_do_expand(png_row_infop row_info, png_bytep row,
             {
                case 1:
                {
             {
                case 1:
                {

-                  gray *= 0xff;
+                  gray = (png_uint_16)((gray&0x01)*0xff);

                   sp = row + (png_size_t)((row_width - 1) >> 3);
                   dp = row + (png_size_t)row_width - 1;
                   sp = row + (png_size_t)((row_width - 1) >> 3);
                   dp = row + (png_size_t)row_width - 1;

-                  shift = 7 - (int)((row_width + 7) & 7);
+                  shift = 7 - (int)((row_width + 7) & 0x07);

                   for (i = 0; i < row_width; i++)
                   {
                   for (i = 0; i < row_width; i++)
                   {

-                     if ((*sp >> shift) & 0x1)
+                     if ((*sp >> shift) & 0x01)

                         *dp = 0xff;
                      else
                         *dp = 0;
                         *dp = 0xff;
                      else
                         *dp = 0;


@@ -3473,15 +3625,16 @@ png_do_expand(png_row_infop row_info, png_bytep row,
                   }
                   break;
                }
                   }
                   break;
                }

+

                case 2:
                {
                case 2:
                {

-                  gray *= 0x55;
+                  gray = (png_uint_16)((gray&0x03)*0x55);

                   sp = row + (png_size_t)((row_width - 1) >> 2);
                   dp = row + (png_size_t)row_width - 1;
                   sp = row + (png_size_t)((row_width - 1) >> 2);
                   dp = row + (png_size_t)row_width - 1;

-                  shift = (int)((3 - ((row_width + 3) & 3)) << 1);
+                  shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);

                   for (i = 0; i < row_width; i++)
                   {
                   for (i = 0; i < row_width; i++)
                   {

-                     value = (*sp >> shift) & 0x3;
+                     value = (*sp >> shift) & 0x03;

                      *dp = (png_byte)(value | (value << 2) | (value << 4) |
                         (value << 6));
                      if (shift == 6)
                      *dp = (png_byte)(value | (value << 2) | (value << 4) |
                         (value << 6));
                      if (shift == 6)


@@ -3496,15 +3649,16 @@ png_do_expand(png_row_infop row_info, png_bytep row,
                   }
                   break;
                }
                   }
                   break;
                }

+

                case 4:
                {
                case 4:
                {

-                  gray *= 0x11;
+                  gray = (png_uint_16)((gray&0x0f)*0x11);

                   sp = row + (png_size_t)((row_width - 1) >> 1);
                   dp = row + (png_size_t)row_width - 1;
                   sp = row + (png_size_t)((row_width - 1) >> 1);
                   dp = row + (png_size_t)row_width - 1;

-                  shift = (int)((1 - ((row_width + 1) & 1)) << 2);
+                  shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);

                   for (i = 0; i < row_width; i++)
                   {
                   for (i = 0; i < row_width; i++)
                   {

-                     value = (*sp >> shift) & 0xf;
+                     value = (*sp >> shift) & 0x0f;

                      *dp = (png_byte)(value | (value << 4));
                      if (shift == 4)
                      {
                      *dp = (png_byte)(value | (value << 4));
                      if (shift == 4)
                      {


@@ -3519,6 +3673,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
                   break;
                }
             }
                   break;
                }
             }

+

             row_info->bit_depth = 8;
             row_info->pixel_depth = 8;
             row_info->rowbytes = row_width;
             row_info->bit_depth = 8;
             row_info->pixel_depth = 8;
             row_info->rowbytes = row_width;


@@ -3528,6 +3683,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
          {
             if (row_info->bit_depth == 8)
             {
          {
             if (row_info->bit_depth == 8)
             {

+               gray = gray & 0xff;

                sp = row + (png_size_t)row_width - 1;
                dp = row + (png_size_t)(row_width << 1) - 1;
                for (i = 0; i < row_width; i++)
                sp = row + (png_size_t)row_width - 1;
                dp = row + (png_size_t)(row_width << 1) - 1;
                for (i = 0; i < row_width; i++)


@@ -3539,14 +3695,16 @@ png_do_expand(png_row_infop row_info, png_bytep row,
                   *dp-- = *sp--;
                }
             }
                   *dp-- = *sp--;
                }
             }

+

             else if (row_info->bit_depth == 16)
             {
             else if (row_info->bit_depth == 16)
             {

+               png_byte gray_high = (gray >> 8) & 0xff;
+               png_byte gray_low = gray & 0xff;

                sp = row + row_info->rowbytes - 1;
                dp = row + (row_info->rowbytes << 1) - 1;
                for (i = 0; i < row_width; i++)
                {
                sp = row + row_info->rowbytes - 1;
                dp = row + (row_info->rowbytes << 1) - 1;
                for (i = 0; i < row_width; i++)
                {

-                  if (((png_uint_16)*(sp) |
-                     ((png_uint_16)*(sp - 1) << 8)) == gray)
+                  if (*(sp - 1) == gray_high && *(sp) == gray_low)

                   {
                      *dp-- = 0;
                      *dp-- = 0;
                   {
                      *dp-- = 0;
                      *dp-- = 0;


@@ -3560,24 +3718,26 @@ png_do_expand(png_row_infop row_info, png_bytep row,
                   *dp-- = *sp--;
                }
             }
                   *dp-- = *sp--;
                }
             }

+

             row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
             row_info->channels = 2;
             row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
             row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
             row_info->channels = 2;
             row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);

-            row_info->rowbytes =
-               ((row_width * row_info->pixel_depth) >> 3);
+            row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+               row_width);

          }
       }
       else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value)
       {
          if (row_info->bit_depth == 8)
          {
          }
       }
       else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value)
       {
          if (row_info->bit_depth == 8)
          {

+            png_byte red = trans_value->red & 0xff;
+            png_byte green = trans_value->green & 0xff;
+            png_byte blue = trans_value->blue & 0xff;

             sp = row + (png_size_t)row_info->rowbytes - 1;
             dp = row + (png_size_t)(row_width << 2) - 1;
             for (i = 0; i < row_width; i++)
             {
             sp = row + (png_size_t)row_info->rowbytes - 1;
             dp = row + (png_size_t)(row_width << 2) - 1;
             for (i = 0; i < row_width; i++)
             {

-               if (*(sp - 2) == trans_value->red &&
-                  *(sp - 1) == trans_value->green &&
-                  *(sp - 0) == trans_value->blue)
+               if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)

                   *dp-- = 0;
                else
                   *dp-- = 0xff;
                   *dp-- = 0;
                else
                   *dp-- = 0xff;


@@ -3588,16 +3748,22 @@ png_do_expand(png_row_infop row_info, png_bytep row,
          }
          else if (row_info->bit_depth == 16)
          {
          }
          else if (row_info->bit_depth == 16)
          {

+            png_byte red_high = (trans_value->red >> 8) & 0xff;
+            png_byte green_high = (trans_value->green >> 8) & 0xff;
+            png_byte blue_high = (trans_value->blue >> 8) & 0xff;
+            png_byte red_low = trans_value->red & 0xff;
+            png_byte green_low = trans_value->green & 0xff;
+            png_byte blue_low = trans_value->blue & 0xff;

             sp = row + row_info->rowbytes - 1;
             dp = row + (png_size_t)(row_width << 3) - 1;
             for (i = 0; i < row_width; i++)
             {
             sp = row + row_info->rowbytes - 1;
             dp = row + (png_size_t)(row_width << 3) - 1;
             for (i = 0; i < row_width; i++)
             {

-               if ((((png_uint_16)*(sp - 4) |
-                  ((png_uint_16)*(sp - 5) << 8)) == trans_value->red) &&
-                  (((png_uint_16)*(sp - 2) |
-                  ((png_uint_16)*(sp - 3) << 8)) == trans_value->green) &&
-                  (((png_uint_16)*(sp - 0) |
-                  ((png_uint_16)*(sp - 1) << 8)) == trans_value->blue))
+               if (*(sp - 5) == red_high &&
+                  *(sp - 4) == red_low &&
+                  *(sp - 3) == green_high &&
+                  *(sp - 2) == green_low &&
+                  *(sp - 1) == blue_high &&
+                  *(sp    ) == blue_low)

                {
                   *dp-- = 0;
                   *dp-- = 0;
                {
                   *dp-- = 0;
                   *dp-- = 0;


@@ -3618,26 +3784,23 @@ png_do_expand(png_row_infop row_info, png_bytep row,
          row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
          row_info->channels = 4;
          row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
          row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
          row_info->channels = 4;
          row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);

-         row_info->rowbytes =
-            ((row_width * row_info->pixel_depth) >> 3);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);

       }
    }
 }
 #endif
 
       }
    }
 }
 #endif
 

-#if defined(PNG_READ_DITHER_SUPPORTED)
-void
-png_do_dither(png_row_infop row_info, png_bytep row,
-    png_bytep palette_lookup, png_bytep dither_lookup)
+#ifdef PNG_READ_QUANTIZE_SUPPORTED
+void /* PRIVATE */
+png_do_quantize(png_row_infop row_info, png_bytep row,
+    png_bytep palette_lookup, png_bytep quantize_lookup)

 {
    png_bytep sp, dp;
    png_uint_32 i;
    png_uint_32 row_width=row_info->width;
 
 {
    png_bytep sp, dp;
    png_uint_32 i;
    png_uint_32 row_width=row_info->width;
 

-   png_debug(1, "in png_do_dither\n");
-#if defined(PNG_USELESS_TESTS_SUPPORTED)
-   if (row != NULL && row_info != NULL)
-#endif
+   png_debug(1, "in png_do_quantize");
+

    {
       if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
          palette_lookup && row_info->bit_depth == 8)
    {
       if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
          palette_lookup && row_info->bit_depth == 8)


@@ -3651,29 +3814,28 @@ png_do_dither(png_row_infop row_info, png_bytep row,
             g = *sp++;
             b = *sp++;
 
             g = *sp++;
             b = *sp++;
 

-            /* this looks real messy, but the compiler will reduce
-               it down to a reasonable formula.  For example, with
-               5 bits per color, we get:
-               p = (((r >> 3) & 0x1f) << 10) |
-                  (((g >> 3) & 0x1f) << 5) |
-                  ((b >> 3) & 0x1f);
-               */
-            p = (((r >> (8 - PNG_DITHER_RED_BITS)) &
-               ((1 << PNG_DITHER_RED_BITS) - 1)) <<
-               (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) |
-               (((g >> (8 - PNG_DITHER_GREEN_BITS)) &
-               ((1 << PNG_DITHER_GREEN_BITS) - 1)) <<
-               (PNG_DITHER_BLUE_BITS)) |
-               ((b >> (8 - PNG_DITHER_BLUE_BITS)) &
-               ((1 << PNG_DITHER_BLUE_BITS) - 1));
+            /* This looks real messy, but the compiler will reduce
+             * it down to a reasonable formula.  For example, with
+             * 5 bits per color, we get:
+             * p = (((r >> 3) & 0x1f) << 10) |
+             *    (((g >> 3) & 0x1f) << 5) |
+             *    ((b >> 3) & 0x1f);
+             */
+            p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
+               ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
+               (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
+               (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
+               ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
+               (PNG_QUANTIZE_BLUE_BITS)) |
+               ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
+               ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));

 
             *dp++ = palette_lookup[p];
          }
          row_info->color_type = PNG_COLOR_TYPE_PALETTE;
          row_info->channels = 1;
          row_info->pixel_depth = row_info->bit_depth;
 
             *dp++ = palette_lookup[p];
          }
          row_info->color_type = PNG_COLOR_TYPE_PALETTE;
          row_info->channels = 1;
          row_info->pixel_depth = row_info->bit_depth;

-         row_info->rowbytes =
-             ((row_width * row_info->pixel_depth + 7) >> 3);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);

       }
       else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
          palette_lookup != NULL && row_info->bit_depth == 8)
       }
       else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
          palette_lookup != NULL && row_info->bit_depth == 8)


@@ -3688,253 +3850,354 @@ png_do_dither(png_row_infop row_info, png_bytep row,
             b = *sp++;
             sp++;
 
             b = *sp++;
             sp++;
 

-            p = (((r >> (8 - PNG_DITHER_RED_BITS)) &
-               ((1 << PNG_DITHER_RED_BITS) - 1)) <<
-               (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) |
-               (((g >> (8 - PNG_DITHER_GREEN_BITS)) &
-               ((1 << PNG_DITHER_GREEN_BITS) - 1)) <<
-               (PNG_DITHER_BLUE_BITS)) |
-               ((b >> (8 - PNG_DITHER_BLUE_BITS)) &
-               ((1 << PNG_DITHER_BLUE_BITS) - 1));
+            p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
+               ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
+               (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
+               (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
+               ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
+               (PNG_QUANTIZE_BLUE_BITS)) |
+               ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
+               ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));

 
             *dp++ = palette_lookup[p];
          }
          row_info->color_type = PNG_COLOR_TYPE_PALETTE;
          row_info->channels = 1;
          row_info->pixel_depth = row_info->bit_depth;
 
             *dp++ = palette_lookup[p];
          }
          row_info->color_type = PNG_COLOR_TYPE_PALETTE;
          row_info->channels = 1;
          row_info->pixel_depth = row_info->bit_depth;

-         row_info->rowbytes =
-            ((row_width * row_info->pixel_depth + 7) >> 3);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);

       }
       else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
       }
       else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&

-         dither_lookup && row_info->bit_depth == 8)
+         quantize_lookup && row_info->bit_depth == 8)

       {
          sp = row;
          for (i = 0; i < row_width; i++, sp++)
          {
       {
          sp = row;
          for (i = 0; i < row_width; i++, sp++)
          {

-            *sp = dither_lookup[*sp];
+            *sp = quantize_lookup[*sp];

          }
       }
    }
 }
 #endif
 
          }
       }
    }
 }
 #endif
 

-#if defined(PNG_READ_GAMMA_SUPPORTED)
-static int png_gamma_shift[] =
-   {0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0};
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+#ifdef PNG_READ_GAMMA_SUPPORTED
+static PNG_CONST int png_gamma_shift[] =
+   {0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0, 0x00};

 
 /* We build the 8- or 16-bit gamma tables here.  Note that for 16-bit
  * tables, we don't make a full table if we are reducing to 8-bit in
  * the future.  Note also how the gamma_16 tables are segmented so that
  * we don't need to allocate > 64K chunks for a full 16-bit table.
 
 /* We build the 8- or 16-bit gamma tables here.  Note that for 16-bit
  * tables, we don't make a full table if we are reducing to 8-bit in
  * the future.  Note also how the gamma_16 tables are segmented so that
  * we don't need to allocate > 64K chunks for a full 16-bit table.

+ *
+ * See the PNG extensions document for an integer algorithm for creating
+ * the gamma tables.  Maybe we will implement that here someday.
+ *
+ * We should only reach this point if
+ *
+ *      the file_gamma is known (i.e., the gAMA or sRGB chunk is present,
+ *      or the application has provided a file_gamma)
+ *
+ *   AND
+ *      {
+ *         the screen_gamma is known
+ *
+ *      OR
+ *
+ *         RGB_to_gray transformation is being performed
+ *      }
+ *
+ *   AND
+ *      {
+ *         the screen_gamma is different from the reciprocal of the
+ *         file_gamma by more than the specified threshold
+ *
+ *      OR
+ *
+ *         a background color has been specified and the file_gamma
+ *         and screen_gamma are not 1.0, within the specified threshold.
+ *      }

  */
  */

-void
-png_build_gamma_table(png_structp png_ptr)
+
+void /* PRIVATE */
+png_build_gamma_table(png_structp png_ptr, png_byte bit_depth)

 {
 {

-  png_debug(1, "in png_build_gamma_table\n");
-  if(png_ptr->gamma != 0.0)
+  png_debug(1, "in png_build_gamma_table");
+
+  if (bit_depth <= 8)

   {
   {

-   if (png_ptr->bit_depth <= 8)
-   {
-      int i;
-      double g;
+     int i;
+     double g;

 
 

-      if (png_ptr->screen_gamma > .000001)
-         g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
-      else
-         g = 1.0;
+     if (png_ptr->screen_gamma > .000001)
+        g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);

 
 

-      png_ptr->gamma_table = (png_bytep)png_malloc(png_ptr,
-         (png_uint_32)256);
+     else
+        g = 1.0;

 
 

-      for (i = 0; i < 256; i++)
-      {
-         png_ptr->gamma_table[i] = (png_byte)(pow((double)i / 255.0,
-            g) * 255.0 + .5);
-      }
+     png_ptr->gamma_table = (png_bytep)png_malloc(png_ptr,
+        (png_uint_32)256);
+
+     for (i = 0; i < 256; i++)
+     {
+        png_ptr->gamma_table[i] = (png_byte)(pow((double)i / 255.0,
+           g) * 255.0 + .5);
+     }

 
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
 
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \

-    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-      if (png_ptr->transformations & (PNG_BACKGROUND | PNG_RGB_TO_GRAY))
-      {
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+     if (png_ptr->transformations & ((PNG_BACKGROUND) | PNG_RGB_TO_GRAY))
+     {

 
 

-         g = 1.0 / (png_ptr->gamma);
+        g = 1.0 / (png_ptr->gamma);

 
 

-         png_ptr->gamma_to_1 = (png_bytep)png_malloc(png_ptr,
-            (png_uint_32)256);
+        png_ptr->gamma_to_1 = (png_bytep)png_malloc(png_ptr,
+           (png_uint_32)256);

 
 

-         for (i = 0; i < 256; i++)
-         {
-            png_ptr->gamma_to_1[i] = (png_byte)(pow((double)i / 255.0,
-               g) * 255.0 + .5);
-         }
+        for (i = 0; i < 256; i++)
+        {
+           png_ptr->gamma_to_1[i] = (png_byte)(pow((double)i / 255.0,
+              g) * 255.0 + .5);
+        }

 
 

-         
-         png_ptr->gamma_from_1 = (png_bytep)png_malloc(png_ptr,
-            (png_uint_32)256);

 
 

-         if(png_ptr->screen_gamma > 0.000001)
-            g = 1.0 / png_ptr->screen_gamma;
-         else
-            g = png_ptr->gamma;   /* probably doing rgb_to_gray */
+        png_ptr->gamma_from_1 = (png_bytep)png_malloc(png_ptr,
+           (png_uint_32)256);

 
 

-         for (i = 0; i < 256; i++)
-         {
-            png_ptr->gamma_from_1[i] = (png_byte)(pow((double)i / 255.0,
-               g) * 255.0 + .5);
+        if (png_ptr->screen_gamma > 0.000001)
+           g = 1.0 / png_ptr->screen_gamma;

 
 

-         }
-      }
+        else
+           g = png_ptr->gamma;   /* Probably doing rgb_to_gray */
+
+        for (i = 0; i < 256; i++)
+        {
+           png_ptr->gamma_from_1[i] = (png_byte)(pow((double)i / 255.0,
+              g) * 255.0 + .5);
+
+        }
+     }

 #endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
 #endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */

-   }
-   else
-   {
-      double g;
-      int i, j, shift, num;
-      int sig_bit;
-      png_uint_32 ig;
+  }
+  else
+  {
+     double g;
+     int i, j, shift, num;
+     int sig_bit;
+     png_uint_32 ig;

 
 

-      if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
-      {
-         sig_bit = (int)png_ptr->sig_bit.red;
-         if ((int)png_ptr->sig_bit.green > sig_bit)
-            sig_bit = png_ptr->sig_bit.green;
-         if ((int)png_ptr->sig_bit.blue > sig_bit)
-            sig_bit = png_ptr->sig_bit.blue;
-      }
-      else
-      {
-         sig_bit = (int)png_ptr->sig_bit.gray;
-      }
+     if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
+     {
+        sig_bit = (int)png_ptr->sig_bit.red;

 
 

-      if (sig_bit > 0)
-         shift = 16 - sig_bit;
-      else
-         shift = 0;
+        if ((int)png_ptr->sig_bit.green > sig_bit)
+           sig_bit = png_ptr->sig_bit.green;

 
 

-      if (png_ptr->transformations & PNG_16_TO_8)
-      {
-         if (shift < (16 - PNG_MAX_GAMMA_8))
-            shift = (16 - PNG_MAX_GAMMA_8);
-      }
+        if ((int)png_ptr->sig_bit.blue > sig_bit)
+           sig_bit = png_ptr->sig_bit.blue;
+     }
+     else
+     {
+        sig_bit = (int)png_ptr->sig_bit.gray;
+     }

 
 

-      if (shift > 8)
-         shift = 8;
-      if (shift < 0)
-         shift = 0;
+     if (sig_bit > 0)
+        shift = 16 - sig_bit;

 
 

-      png_ptr->gamma_shift = (png_byte)shift;
+     else
+        shift = 0;

 
 

-      num = (1 << (8 - shift));
+     if (png_ptr->transformations & PNG_16_TO_8)
+     {
+        if (shift < (16 - PNG_MAX_GAMMA_8))
+           shift = (16 - PNG_MAX_GAMMA_8);
+     }

 
 

-      if (png_ptr->screen_gamma > .000001)
-         g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
-      else
-         g = 1.0;
+     if (shift > 8)
+        shift = 8;

 
 

-      png_ptr->gamma_16_table = (png_uint_16pp)png_malloc(png_ptr,
-         (png_uint_32)(num * sizeof (png_uint_16p)));
+     if (shift < 0)
+        shift = 0;

 
 

-      if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND))
-      {
-         double fin, fout;
-         png_uint_32 last, max;
+     png_ptr->gamma_shift = (png_byte)shift;

 
 

-         for (i = 0; i < num; i++)
-         {
-            png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
-               (png_uint_32)(256 * sizeof (png_uint_16)));
-         }
+     num = (1 << (8 - shift));

 
 

-         g = 1.0 / g;
-         last = 0;
-         for (i = 0; i < 256; i++)
-         {
-            fout = ((double)i + 0.5) / 256.0;
-            fin = pow(fout, g);
-            max = (png_uint_32)(fin * (double)((png_uint_32)num << 8));
-            while (last <= max)
-            {
-               png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
-                  [(int)(last >> (8 - shift))] = (png_uint_16)(
-                  (png_uint_16)i | ((png_uint_16)i << 8));
-               last++;
-            }
-         }
-         while (last < ((png_uint_32)num << 8))
-         {
-            png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
-               [(int)(last >> (8 - shift))] = (png_uint_16)65535L;
-            last++;
-         }
-      }
-      else
-      {
-         for (i = 0; i < num; i++)
-         {
-            png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
-               (png_uint_32)(256 * sizeof (png_uint_16)));
+     if (png_ptr->screen_gamma > .000001)
+        g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
+     else
+        g = 1.0;

 
 

-            ig = (((png_uint_32)i * (png_uint_32)png_gamma_shift[shift]) >> 4);
-            for (j = 0; j < 256; j++)
-            {
-               png_ptr->gamma_16_table[i][j] =
-                  (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
-                     65535.0, g) * 65535.0 + .5);
-            }
-         }
-      }
+     png_ptr->gamma_16_table = (png_uint_16pp)png_calloc(png_ptr,
+        (png_uint_32)(num * png_sizeof(png_uint_16p)));
+
+     if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND))
+     {
+        double fin, fout;
+        png_uint_32 last, max;
+
+        for (i = 0; i < num; i++)
+        {
+           png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
+              (png_uint_32)(256 * png_sizeof(png_uint_16)));
+        }
+
+        g = 1.0 / g;
+        last = 0;
+        for (i = 0; i < 256; i++)
+        {
+           fout = ((double)i + 0.5) / 256.0;
+           fin = pow(fout, g);
+           max = (png_uint_32)(fin * (double)((png_uint_32)num << 8));
+           while (last <= max)
+           {
+              png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
+                 [(int)(last >> (8 - shift))] = (png_uint_16)(
+                 (png_uint_16)i | ((png_uint_16)i << 8));
+              last++;
+           }
+        }
+        while (last < ((png_uint_32)num << 8))
+        {
+           png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
+              [(int)(last >> (8 - shift))] = (png_uint_16)65535L;
+           last++;
+        }
+     }
+     else
+     {
+        for (i = 0; i < num; i++)
+        {
+           png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
+              (png_uint_32)(256 * png_sizeof(png_uint_16)));
+
+           ig = (((png_uint_32)i * (png_uint_32)png_gamma_shift[shift]) >> 4);
+
+           for (j = 0; j < 256; j++)
+           {
+              png_ptr->gamma_16_table[i][j] =
+                 (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
+                    65535.0, g) * 65535.0 + .5);
+           }
+        }
+     }

 
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
 
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \

-    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
-      if (png_ptr->transformations & (PNG_BACKGROUND | PNG_RGB_TO_GRAY))
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+     if (png_ptr->transformations & (PNG_BACKGROUND | PNG_RGB_TO_GRAY))
+     {
+
+        g = 1.0 / (png_ptr->gamma);
+
+        png_ptr->gamma_16_to_1 = (png_uint_16pp)png_calloc(png_ptr,
+           (png_uint_32)(num * png_sizeof(png_uint_16p )));
+
+        for (i = 0; i < num; i++)
+        {
+           png_ptr->gamma_16_to_1[i] = (png_uint_16p)png_malloc(png_ptr,
+              (png_uint_32)(256 * png_sizeof(png_uint_16)));
+
+           ig = (((png_uint_32)i *
+              (png_uint_32)png_gamma_shift[shift]) >> 4);
+           for (j = 0; j < 256; j++)
+           {
+              png_ptr->gamma_16_to_1[i][j] =
+                 (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
+                    65535.0, g) * 65535.0 + .5);
+           }
+        }
+
+        if (png_ptr->screen_gamma > 0.000001)
+           g = 1.0 / png_ptr->screen_gamma;
+
+        else
+           g = png_ptr->gamma;   /* Probably doing rgb_to_gray */
+
+        png_ptr->gamma_16_from_1 = (png_uint_16pp)png_calloc(png_ptr,
+           (png_uint_32)(num * png_sizeof(png_uint_16p)));
+
+        for (i = 0; i < num; i++)
+        {
+           png_ptr->gamma_16_from_1[i] = (png_uint_16p)png_malloc(png_ptr,
+              (png_uint_32)(256 * png_sizeof(png_uint_16)));
+
+           ig = (((png_uint_32)i *
+              (png_uint_32)png_gamma_shift[shift]) >> 4);
+
+           for (j = 0; j < 256; j++)
+           {
+              png_ptr->gamma_16_from_1[i][j] =
+                 (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
+                    65535.0, g) * 65535.0 + .5);
+           }
+        }
+     }
+#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
+  }
+}
+#endif
+/* To do: install integer version of png_build_gamma_table here */
+#endif
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+/* Undoes intrapixel differencing  */
+void /* PRIVATE */
+png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_read_intrapixel");
+
+   if (
+       (row_info->color_type & PNG_COLOR_MASK_COLOR))
+   {
+      int bytes_per_pixel;
+      png_uint_32 row_width = row_info->width;
+      if (row_info->bit_depth == 8)

       {
       {

+         png_bytep rp;
+         png_uint_32 i;

 
 

-         g = 1.0 / (png_ptr->gamma);
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 3;

 
 

-         png_ptr->gamma_16_to_1 = (png_uint_16pp)png_malloc(png_ptr,
-            (png_uint_32)(num * sizeof (png_uint_16p )));
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 4;

 
 

-         for (i = 0; i < num; i++)
-         {
-            png_ptr->gamma_16_to_1[i] = (png_uint_16p)png_malloc(png_ptr,
-               (png_uint_32)(256 * sizeof (png_uint_16)));
+         else
+            return;

 
 

-            ig = (((png_uint_32)i *
-               (png_uint_32)png_gamma_shift[shift]) >> 4);
-            for (j = 0; j < 256; j++)
-            {
-               png_ptr->gamma_16_to_1[i][j] =
-                  (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
-                     65535.0, g) * 65535.0 + .5);
-            }
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            *(rp) = (png_byte)((256 + *rp + *(rp+1))&0xff);
+            *(rp+2) = (png_byte)((256 + *(rp+2) + *(rp+1))&0xff);

          }
          }

+      }
+      else if (row_info->bit_depth == 16)
+      {
+         png_bytep rp;
+         png_uint_32 i;

 
 

-         if(png_ptr->screen_gamma > 0.000001)
-            g = 1.0 / png_ptr->screen_gamma;
-         else
-            g = png_ptr->gamma;   /* probably doing rgb_to_gray */
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 6;

 
 

-         png_ptr->gamma_16_from_1 = (png_uint_16pp)png_malloc(png_ptr,
-            (png_uint_32)(num * sizeof (png_uint_16p)));
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 8;

 
 

-         for (i = 0; i < num; i++)
-         {
-            png_ptr->gamma_16_from_1[i] = (png_uint_16p)png_malloc(png_ptr,
-               (png_uint_32)(256 * sizeof (png_uint_16)));
+         else
+            return;

 
 

-            ig = (((png_uint_32)i *
-               (png_uint_32)png_gamma_shift[shift]) >> 4);
-            for (j = 0; j < 256; j++)
-            {
-               png_ptr->gamma_16_from_1[i][j] =
-                  (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
-                     65535.0, g) * 65535.0 + .5);
-            }
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            png_uint_32 s0   = (*(rp    ) << 8) | *(rp + 1);
+            png_uint_32 s1   = (*(rp + 2) << 8) | *(rp + 3);
+            png_uint_32 s2   = (*(rp + 4) << 8) | *(rp + 5);
+            png_uint_32 red  = (png_uint_32)((s0 + s1 + 65536L) & 0xffffL);
+            png_uint_32 blue = (png_uint_32)((s2 + s1 + 65536L) & 0xffffL);
+            *(rp  ) = (png_byte)((red >> 8) & 0xff);
+            *(rp+1) = (png_byte)(red & 0xff);
+            *(rp+4) = (png_byte)((blue >> 8) & 0xff);
+            *(rp+5) = (png_byte)(blue & 0xff);

          }
       }
          }
       }

-#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */

    }
    }

- }

 }
 }

-#endif
-
+#endif /* PNG_MNG_FEATURES_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED */