Rename wxWebHistoryItem to wxWebViewHistoryItem.

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

diff --git a/src/png/pngrtran.c b/src/png/pngrtran.c
index ed02e10fe516fa6c5d3486419882a73987b44086..b5e8f1a26f2b1386d287359dd1a19e82abc4fde5 100644 (file)
--- a/src/png/pngrtran.c
+++ b/src/png/pngrtran.c
@@ -1,67 +1,87 @@
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *

- * libpng 1.2.5rc3 - September 18, 2002
- * For conditions of distribution and use, see copyright notice in png.h
- * Copyright (c) 1998-2002 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.)
  *
  * (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.
  * Transformations that are used in both reading and writing are
  * in pngtrans.c.
  */
 
  * This file contains functions optionally called by an application
  * in order to tell libpng how to handle data when reading a PNG.
  * Transformations that are used in both reading and writing are
  * in pngtrans.c.
  */
 

-#define PNG_INTERNAL
+#define PNG_NO_PEDANTIC_WARNINGS

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

+#ifdef PNG_READ_SUPPORTED
+#include "pngpriv.h"

 
 /* Set the action on getting a CRC error for an ancillary or critical chunk. */
 void PNGAPI
 png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
 {
 
 /* Set the action on getting a CRC error for an ancillary or critical chunk. */
 void PNGAPI
 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;


@@ -71,13 +91,16 @@ png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
 
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
     defined(PNG_FLOATING_POINT_SUPPORTED)
 
 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
     defined(PNG_FLOATING_POINT_SUPPORTED)

-/* handle alpha and tRNS via a background color */
+/* 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)
 {
 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_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");


@@ -85,50 +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_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->mode |= PNG_BACKGROUND_IS_GRAY;

 }
 #endif
 
 }
 #endif
 

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

 void PNGAPI
 png_set_strip_alpha(png_structp png_ptr)
 {
 void PNGAPI
 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.
  */
 


@@ -142,21 +161,24 @@ typedef png_dsort FAR *       png_dsortp;
 typedef png_dsort FAR * FAR * png_dsortpp;
 
 void PNGAPI
 typedef png_dsort FAR * FAR * png_dsortpp;
 
 void PNGAPI

-png_set_dither(png_structp png_ptr, png_colorp palette,
+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 (!full_dither)
+   if (png_ptr == NULL)
+      return;
+   png_ptr->transformations |= PNG_QUANTIZE;
+
+   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)


@@ -164,40 +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;
 

-         /* initialize an array to sort colors */
-         png_ptr->dither_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 dither_sort array */
+         /* Initialize the quantize_sort array */

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

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

                {
                   png_byte t;
 
                {
                   png_byte t;
 

-                  t = png_ptr->dither_sort[j];
-                  png_ptr->dither_sort[j] = png_ptr->dither_sort[j + 1];
-                  png_ptr->dither_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;
                }
             }


@@ -205,20 +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)png_ptr->dither_sort[i] >= maximum_colors)
+               if ((int)png_ptr->quantize_sort[i] >= maximum_colors)

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

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

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


@@ -227,37 +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)png_ptr->dither_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)png_ptr->dither_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++)
                   {


@@ -271,61 +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, png_ptr->dither_sort);
-         png_ptr->dither_sort=NULL;
+         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;
          png_dsortp t;
          png_dsortpp hash;
 
          int i;
          int max_d;
          int num_new_palette;
          png_dsortp t;
          png_dsortpp hash;
 

-         t=NULL;
+         t = NULL;

 
 

-         /* initialize palette index arrays */
+         /* Initialize palette index arrays */

          png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
          png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,

-            (png_uint_32)(num_palette * sizeof (png_byte)));
+            (png_uint_32)(num_palette * png_sizeof(png_byte)));

          png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
          png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,

-            (png_uint_32)(num_palette * sizeof (png_byte)));
+            (png_uint_32)(num_palette * png_sizeof(png_byte)));

 
 

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

          for (i = 0; i < num_palette; i++)
          {
             png_ptr->index_to_palette[i] = (png_byte)i;
             png_ptr->palette_to_index[i] = (png_byte)i;
          }
 
          for (i = 0; i < num_palette; 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)


@@ -344,7 +367,7 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
                   {
 
                      t = (png_dsortp)png_malloc_warn(png_ptr,
                   {
 
                      t = (png_dsortp)png_malloc_warn(png_ptr,

-                         (png_uint_32)(sizeof(png_dsort)));
+                         (png_uint_32)(png_sizeof(png_dsort)));

                      if (t == NULL)
                          break;
                      t->next = hash[d];
                      if (t == NULL)
                          break;
                      t->next = hash[d];


@@ -387,19 +410,19 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
                         num_new_palette--;
                         palette[png_ptr->index_to_palette[j]]
                           = palette[num_new_palette];
                         num_new_palette--;
                         palette[png_ptr->index_to_palette[j]]
                           = palette[num_new_palette];

-                        if (!full_dither)
+                        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] ==
+                              if (png_ptr->quantize_index[k] ==

                                  png_ptr->index_to_palette[j])
                                  png_ptr->index_to_palette[j])

-                                 png_ptr->dither_index[k] =
+                                 png_ptr->quantize_index[k] =

                                     png_ptr->index_to_palette[next_j];
                                     png_ptr->index_to_palette[next_j];

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

                                  num_new_palette)
                                  num_new_palette)

-                                 png_ptr->dither_index[k] =
+                                 png_ptr->quantize_index[k] =

                                     png_ptr->index_to_palette[j];
                            }
                         }
                                     png_ptr->index_to_palette[j];
                            }
                         }


@@ -409,8 +432,10 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
                         png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
                            = png_ptr->palette_to_index[num_new_palette];
 
                         png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
                            = png_ptr->palette_to_index[num_new_palette];
 

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


@@ -439,8 +464,8 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
          png_free(png_ptr, hash);
          png_free(png_ptr, png_ptr->palette_to_index);
          png_free(png_ptr, png_ptr->index_to_palette);
          png_free(png_ptr, hash);
          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;
+         png_ptr->palette_to_index = NULL;
+         png_ptr->index_to_palette = NULL;

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


@@ -450,50 +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;
 


@@ -510,7 +536,7 @@ 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) && defined(PNG_FLOATING_POINT_SUPPORTED)
 /* Transform the image from the file_gamma to the screen_gamma.  We
 
 #if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
 /* Transform the image from the file_gamma to the screen_gamma.  We


@@ -525,7 +551,11 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
 void PNGAPI
 png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
 {
 void PNGAPI
 png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
 {

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


@@ -535,7 +565,7 @@ png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_EXPAND_SUPPORTED)
+#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.
 /* 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.


@@ -543,8 +573,13 @@ png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
 void PNGAPI
 png_set_expand(png_structp png_ptr)
 {
 void PNGAPI
 png_set_expand(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_expand\n");
-   png_ptr->transformations |= PNG_EXPAND;
+   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
 }
 
 /* GRR 19990627:  the following three functions currently are identical


@@ -559,44 +594,64 @@ png_set_expand(png_structp png_ptr)
  *
  *  More to the point, these functions make it obvious what libpng will be
  *  doing, whereas "expand" can (and does) mean any number of things.
  *
  *  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)
 {
  */
 
 /* Expand paletted images to RGB. */
 void PNGAPI
 png_set_palette_to_rgb(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_expand\n");
-   png_ptr->transformations |= PNG_EXPAND;
+   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
 }
 
 /* Expand grayscale images of less than 8-bit depth to 8 bits. */
 void PNGAPI

-png_set_gray_1_2_4_to_8(png_structp png_ptr)
+png_set_expand_gray_1_2_4_to_8(png_structp png_ptr)

 {
 {

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

 }
 
 }
 

+
+

 /* Expand tRNS chunks to alpha channels. */
 void PNGAPI
 png_set_tRNS_to_alpha(png_structp png_ptr)
 {
 /* Expand tRNS chunks to alpha channels. */
 void PNGAPI
 png_set_tRNS_to_alpha(png_structp png_ptr)
 {

-   png_debug(1, "in png_set_expand\n");
-   png_ptr->transformations |= PNG_EXPAND;
+   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) */
 
 }
 #endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
 

-#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED

 void PNGAPI
 png_set_gray_to_rgb(png_structp png_ptr)
 {
 void PNGAPI
 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)
-#if defined(PNG_FLOATING_POINT_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.
  */


@@ -605,9 +660,11 @@ void PNGAPI
 png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red,
    double green)
 {
 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);
-      png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed);
+   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
 
 }
 #endif
 


@@ -615,35 +672,42 @@ void PNGAPI
 png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action,
    png_fixed_point red, png_fixed_point green)
 {
 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_uint_16 red_int, green_int;
       png_ptr->transformations &= ~PNG_RGB_TO_GRAY;
    }
 #endif
    {
       png_uint_16 red_int, green_int;

-      if(red < 0 || green < 0)
+      if (red < 0 || green < 0)

       {
          red_int   =  6968; /* .212671 * 32768 + .5 */
          green_int = 23434; /* .715160 * 32768 + .5 */
       }
       {
          red_int   =  6968; /* .212671 * 32768 + .5 */
          green_int = 23434; /* .715160 * 32768 + .5 */
       }

-      else if(red + green < 100000L)
+      else if (red + green < 100000L)

       {
       {

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

       }
       else
       {
       }
       else
       {


@@ -653,28 +717,27 @@ png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action,
       }
       png_ptr->rgb_to_gray_red_coeff   = red_int;
       png_ptr->rgb_to_gray_green_coeff = green_int;
       }
       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);
+      png_ptr->rgb_to_gray_blue_coeff  =
+         (png_uint_16)(32768 - red_int - green_int);

    }
 }
 #endif
 
 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
    }
 }
 #endif
 
 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \

-    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
-    defined(PNG_LEGACY_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)
 {
 void PNGAPI
 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");
-#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+   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;
 #endif
    png_ptr->transformations |= PNG_USER_TRANSFORM;
    png_ptr->read_user_transform_fn = read_user_transform_fn;
 #endif

-#ifdef PNG_LEGACY_SUPPORTED
-   if(read_user_transform_fn)
-      png_warning(png_ptr,
-        "This version of libpng does not support user transforms");
-#endif

 }
 #endif
 
 }
 #endif
 


@@ -684,41 +747,89 @@ png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
 void /* PRIVATE */
 png_init_read_transformations(png_structp png_ptr)
 {
 void /* PRIVATE */
 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)

+
+#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 ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
        (png_ptr->transformations & PNG_EXPAND))
    {
       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;
                png_ptr->background.red = png_ptr->background.green
                  =  png_ptr->background.blue = png_ptr->background.gray;
          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;

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

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

+               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:
                png_ptr->background.red = png_ptr->background.green
                  = png_ptr->background.blue = png_ptr->background.gray;
             case 16:
                png_ptr->background.red = png_ptr->background.green
                  = png_ptr->background.blue = png_ptr->background.gray;


@@ -734,19 +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] = (png_byte)(255 - png_ptr->trans[i]);
+                 png_ptr->trans_alpha[i] = (png_byte)(255 - png_ptr->trans_alpha[i]);

            }
         }
 #endif
            }
         }
 #endif


@@ -764,27 +876,28 @@ png_init_read_transformations(png_structp png_ptr)
        && (fabs(png_ptr->screen_gamma * png_ptr->gamma - 1.0)
          < PNG_GAMMA_THRESHOLD))
    {
        && (fabs(png_ptr->screen_gamma * png_ptr->gamma - 1.0)
          < PNG_GAMMA_THRESHOLD))
    {

-    int i,k;
+    int i, k;

     k=0;
     for (i=0; i<png_ptr->num_trans; i++)
     {
     k=0;
     for (i=0; i<png_ptr->num_trans; i++)
     {

-      if (png_ptr->trans[i] != 0 && png_ptr->trans[i] != 0xff)
-        k=1; /* partial transparency is present */
+      if (png_ptr->trans_alpha[i] != 0 && png_ptr->trans_alpha[i] != 0xff)
+        k=1; /* Partial transparency is present */

     }
     if (k == 0)
     }
     if (k == 0)

-      png_ptr->transformations &= (~PNG_GAMMA);
+      png_ptr->transformations &= ~PNG_GAMMA;

    }
 
    }
 

-   if (png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY))
+   if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) &&
+        png_ptr->gamma != 0.0)

    {
    {

-      png_build_gamma_table(png_ptr);
-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+      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 and 
-           */
+           /* Could skip if no transparency */

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


@@ -809,10 +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 *


@@ -832,42 +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];
                   }
                }


@@ -878,6 +994,14 @@ 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) */
          else
          }
          /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
          else


@@ -893,10 +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 *


@@ -938,7 +1064,7 @@ png_init_read_transformations(png_structp png_ptr)
          }
       }
       else
          }
       }
       else

-      /* transformation does not include PNG_BACKGROUND */
+      /* Transformation does not include PNG_BACKGROUND */

 #endif /* PNG_READ_BACKGROUND_SUPPORTED */
       if (color_type == PNG_COLOR_TYPE_PALETTE)
       {
 #endif /* PNG_READ_BACKGROUND_SUPPORTED */
       if (color_type == PNG_COLOR_TYPE_PALETTE)
       {


@@ -952,13 +1078,16 @@ 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
 #endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */
    else
 #endif
 #endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */

-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+#ifdef PNG_READ_BACKGROUND_SUPPORTED

    /* No GAMMA transformation */
    if ((png_ptr->transformations & PNG_BACKGROUND) &&
        (color_type == PNG_COLOR_TYPE_PALETTE))
    /* No GAMMA transformation */
    if ((png_ptr->transformations & PNG_BACKGROUND) &&
        (color_type == PNG_COLOR_TYPE_PALETTE))


@@ -974,25 +1103,29 @@ 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 /* PNG_READ_BACKGROUND_SUPPORTED */
 
    }
 #endif /* PNG_READ_BACKGROUND_SUPPORTED */
 

-#if defined(PNG_READ_SHIFT_SUPPORTED)
+#ifdef PNG_READ_SHIFT_SUPPORTED

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


@@ -1019,7 +1152,7 @@ png_init_read_transformations(png_structp png_ptr)
  }
 #if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \
  && !defined(PNG_READ_BACKGROUND_SUPPORTED)
  }
 #if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \
  && !defined(PNG_READ_BACKGROUND_SUPPORTED)

-   if(png_ptr)
+   if (png_ptr)

       return;
 #endif
 }
       return;
 #endif
 }


@@ -1031,13 +1164,15 @@ png_init_read_transformations(png_structp png_ptr)
 void /* PRIVATE */
 png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
 {
 void /* PRIVATE */
 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;


@@ -1047,7 +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;


@@ -1055,7 +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;


@@ -1064,7 +1202,7 @@ 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)
    {
 #ifdef PNG_FLOATING_POINT_SUPPORTED
    if (png_ptr->transformations & PNG_GAMMA)
    {
 #ifdef PNG_FLOATING_POINT_SUPPORTED


@@ -1076,38 +1214,38 @@ png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
    }
 #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) && (info_ptr->bit_depth == 16))
       info_ptr->bit_depth = 8;
 #endif
 
    if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16))
       info_ptr->bit_depth = 8;
 #endif
 

-#if defined(PNG_READ_DITHER_SUPPORTED)
-   if (png_ptr->transformations & PNG_DITHER)
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+   if (png_ptr->transformations & PNG_GRAY_TO_RGB)
+      info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
+#endif
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+   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) ||
    {
       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_RGB_ALPHA)) &&
+          png_ptr->palette_lookup && info_ptr->bit_depth == 8)

       {
          info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
       }
    }
 #endif
 
       {
          info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
       }
    }
 #endif
 

-#if defined(PNG_READ_PACK_SUPPORTED)
+#ifdef PNG_READ_PACK_SUPPORTED

    if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
       info_ptr->bit_depth = 8;
 #endif
 
    if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
       info_ptr->bit_depth = 8;
 #endif
 

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


@@ -1115,44 +1253,45 @@ 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 */
    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++;
    /* 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 0 /* if adding a true alpha channel not just filler */
-      info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
-#endif
+      /* 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)
    }
 #endif
 
 #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
 defined(PNG_READ_USER_TRANSFORM_SUPPORTED)

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

      {
      {

-       if(info_ptr->bit_depth < png_ptr->user_transform_depth)
+       if (info_ptr->bit_depth < png_ptr->user_transform_depth)

          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)
+       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);
          info_ptr->channels = png_ptr->user_transform_channels;
      }
 #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);

 
 

-#if !defined(PNG_READ_EXPAND_SUPPORTED)
-   if(png_ptr)
+   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
+
+#ifndef PNG_READ_EXPAND_SUPPORTED
+   if (png_ptr)

       return;
 #endif
 }
       return;
 #endif
 }


@@ -1164,35 +1303,48 @@ defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
 void /* PRIVATE */
 png_do_read_transformations(png_structp png_ptr)
 {
 void /* PRIVATE */
 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) && !defined(_WIN32_WCE)
+#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);


@@ -1200,73 +1352,78 @@ 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 */
+#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
 
    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
 

-#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)
-#if defined(PNG_READ_GAMMA_SUPPORTED)
+         &(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->background_1),
          png_ptr->gamma_table, png_ptr->gamma_from_1,
          png_ptr->gamma_to_1, png_ptr->gamma_16_table,


@@ -1276,118 +1433,118 @@ From Andreas Dilger e-mail to png-implement, 26 March 1998:
 );
 #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 */
+#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
 
    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
 

-#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 defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
-      if(png_ptr->user_transform_depth)
+      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;
          png_ptr->row_info.bit_depth = png_ptr->user_transform_depth;

-      if(png_ptr->user_transform_channels)
+      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.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_ptr->row_info.width *
-         png_ptr->row_info.pixel_depth+7)>>3;
+      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
 /* 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


@@ -1397,12 +1554,9 @@ From Andreas Dilger e-mail to png-implement, 26 March 1998:
 void /* PRIVATE */
 png_do_unpack(png_row_infop row_info, png_bytep row)
 {
 void /* PRIVATE */
 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;


@@ -1429,6 +1583,7 @@ png_do_unpack(png_row_infop row_info, png_bytep row)
             }
             break;
          }
             }
             break;
          }

+

          case 2:
          {
 
          case 2:
          {
 


@@ -1450,6 +1605,7 @@ 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);
          case 4:
          {
             png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);


@@ -1478,7 +1634,7 @@ 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
 /* 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


@@ -1487,11 +1643,9 @@ png_do_unpack(png_row_infop row_info, png_bytep row)
 void /* PRIVATE */
 png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
 {
 void /* PRIVATE */
 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];


@@ -1541,6 +1695,7 @@ png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
             }
             break;
          }
             }
             break;
          }

+

          case 4:
          {
             png_bytep bp = row;
          case 4:
          {
             png_bytep bp = row;


@@ -1556,6 +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;


@@ -1568,6 +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;


@@ -1588,17 +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 */
+#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)
 {
 void /* PRIVATE */
 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;


@@ -1607,20 +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:


@@ -1643,14 +1800,12 @@ png_do_chop(png_row_infop row_info, png_bytep row)
 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
+#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED

 void /* PRIVATE */
 png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
 {
 void /* PRIVATE */
 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)


@@ -1735,14 +1890,12 @@ png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
+#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED

 void /* PRIVATE */
 png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
 {
 void /* PRIVATE */
 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)


@@ -1833,7 +1986,7 @@ 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 */
 void /* PRIVATE */
 png_do_read_filler(png_row_infop row_info, png_bytep row,
 /* Add filler channel if we have RGB color */
 void /* PRIVATE */
 png_do_read_filler(png_row_infop row_info, png_bytep row,


@@ -1845,14 +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)


@@ -1884,13 +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;


@@ -1907,8 +2058,8 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
          /* 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);


@@ -1924,7 +2075,7 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
    } /* 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)


@@ -1960,13 +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;


@@ -1987,8 +2138,8 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
          /* 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);


@@ -2009,19 +2160,17 @@ png_do_read_filler(png_row_infop row_info, png_bytep row,
 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
-/* expand grayscale files to RGB, with or without alpha */
+#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;
 
 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_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)


@@ -2087,17 +2236,18 @@ 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
  *
  *
  *     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
  *


@@ -2122,11 +2272,9 @@ 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))
    {
       png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
       (row_info->color_type & PNG_COLOR_MASK_COLOR))
    {
       png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;


@@ -2148,14 +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)>>15];
+                       (rc*red + gc*green + bc*blue)>>15];

                   }
                   else
                   }
                   else

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

                }
             }
             else
                }
             }
             else


@@ -2168,13 +2316,13 @@ 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++) = (png_byte)((rc*red+gc*green+bc*blue)>>15);
+                     *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);

                   }
                   else
                   }
                   else

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

                }
             }
          }
                }
             }
          }


@@ -2195,13 +2343,14 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                   green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
                   blue  = (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_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff) >>
                                   png_ptr->gamma_shift][blue>>8];
                                   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];


@@ -2229,7 +2378,7 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                   green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
                   blue  = (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;
                   gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
                   *(dp++) = (png_byte)((gray16>>8) & 0xff);
                      rgb_error |= 1;
                   gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
                   *(dp++) = (png_byte)((gray16>>8) & 0xff);


@@ -2252,7 +2401,7 @@ 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
                              [(rc*red + gc*green + bc*blue)>>15];
                      rgb_error |= 1;
                   *(dp++) =  png_ptr->gamma_from_1
                              [(rc*red + gc*green + bc*blue)>>15];


@@ -2269,9 +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++) =  (png_byte)((gc*red + gc*green + bc*blue)>>8);
+                  *(dp++) =  (png_byte)((rc*red + gc*green + bc*blue)>>15);

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


@@ -2292,18 +2441,19 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                   green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
                   blue  = (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_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_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  = (png_uint_16)((rc * red_1
                      png_uint_16 gray16  = (png_uint_16)((rc * red_1

-                                  + gc * green_1 + bc * blue_1)>>15);
+                         + 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;


@@ -2326,7 +2476,7 @@ png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
                   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;
                   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;
                   gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
                   *(dp++) = (png_byte)((gray16>>8) & 0xff);
                      rgb_error |= 1;
                   gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
                   *(dp++) = (png_byte)((gray16>>8) & 0xff);


@@ -2341,8 +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;
 }


@@ -2361,7 +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;
 


@@ -2371,18 +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;


@@ -2397,197 +2551,16 @@ 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 /* PRIVATE */
-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) && defined(PNG_FLOATING_POINT_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.
  */
 void /* PRIVATE */
 png_do_background(png_row_infop row_info, png_bytep row,
 /* 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 /* PRIVATE */
 png_do_background(png_row_infop row_info, png_bytep row,

-   png_color_16p trans_values, png_color_16p background
-#if defined(PNG_READ_GAMMA_SUPPORTED)
+   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_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,


@@ -2600,13 +2573,11 @@ png_do_background(png_row_infop row_info, png_bytep row,
    png_uint_32 row_width=row_info->width;
    int shift;
 
    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)
       {


@@ -2621,7 +2592,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                   for (i = 0; i < row_width; i++)
                   {
                      if ((png_uint_16)((*sp >> shift) & 0x01)
                   for (i = 0; i < row_width; i++)
                   {
                      if ((png_uint_16)((*sp >> shift) & 0x01)

-                        == trans_values->gray)
+                        == 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);


@@ -2636,9 +2607,10 @@ 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;
                   if (gamma_table != NULL)
                   {
                      sp = row;


@@ -2646,7 +2618,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      for (i = 0; i < row_width; i++)
                      {
                         if ((png_uint_16)((*sp >> shift) & 0x03)
                      for (i = 0; i < row_width; i++)
                      {
                         if ((png_uint_16)((*sp >> shift) & 0x03)

-                            == trans_values->gray)
+                            == 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);


@@ -2676,7 +2648,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      for (i = 0; i < row_width; i++)
                      {
                         if ((png_uint_16)((*sp >> shift) & 0x03)
                      for (i = 0; i < row_width; i++)
                      {
                         if ((png_uint_16)((*sp >> shift) & 0x03)

-                            == trans_values->gray)
+                            == 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);


@@ -2692,9 +2664,10 @@ 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;
                   if (gamma_table != NULL)
                   {
                      sp = row;


@@ -2702,7 +2675,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      for (i = 0; i < row_width; i++)
                      {
                         if ((png_uint_16)((*sp >> shift) & 0x0f)
                      for (i = 0; i < row_width; i++)
                      {
                         if ((png_uint_16)((*sp >> shift) & 0x0f)

-                            == trans_values->gray)
+                            == 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);


@@ -2732,7 +2705,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      for (i = 0; i < row_width; i++)
                      {
                         if ((png_uint_16)((*sp >> shift) & 0x0f)
                      for (i = 0; i < row_width; i++)
                      {
                         if ((png_uint_16)((*sp >> shift) & 0x0f)

-                            == trans_values->gray)
+                            == 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);


@@ -2748,15 +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;
                         }


@@ -2772,7 +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;
                         }


@@ -2780,9 +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;


@@ -2791,9 +2766,9 @@ png_do_background(png_row_infop row_info, png_bytep row,
                         png_uint_16 v;
 
                         v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
                         png_uint_16 v;
 
                         v = (png_uint_16)(((*sp) << 8) + *(sp + 1));

-                        if (v == trans_values->gray)
+                        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);
                         }


@@ -2814,7 +2789,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                         png_uint_16 v;
 
                         v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
                         png_uint_16 v;
 
                         v = (png_uint_16)(((*sp) << 8) + *(sp + 1));

-                        if (v == trans_values->gray)
+                        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);


@@ -2826,19 +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;


@@ -2858,9 +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;


@@ -2871,7 +2847,7 @@ 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)
                {
                   sp = row;
                if (gamma_16 != NULL)
                {
                   sp = row;


@@ -2880,10 +2856,10 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      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)

                      {
                      {

-                        /* 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);


@@ -2915,8 +2891,8 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      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 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);


@@ -2930,11 +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)
                {


@@ -2950,7 +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


@@ -2976,7 +2953,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      {
                         *dp = *sp;
                      }
                      {
                         *dp = *sp;
                      }

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

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


@@ -2993,7 +2970,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
             }
             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)
                {


@@ -3011,17 +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);
                      }

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

                      else if (a == 0)
 #else
                      else
 #endif
                      {
                      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);
                      }

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

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


@@ -3047,7 +3024,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                      {
                         png_memcpy(dp, sp, 2);
                      }
                      {
                         png_memcpy(dp, sp, 2);
                      }

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

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


@@ -3056,7 +3033,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                         *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);
                      }

-#if defined(PNG_READ_GAMMA_SUPPORTED)
+#ifdef PNG_READ_GAMMA_SUPPORTED

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


@@ -3072,11 +3049,12 @@ png_do_background(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)
             {

-#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)
                {


@@ -3094,7 +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;


@@ -3149,7 +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)
                {


@@ -3175,7 +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);


@@ -3260,14 +3238,13 @@ 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
  * or RGB images. If your bit depth is 8, use gamma_table, if it
 /* 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


@@ -3283,11 +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)))
    {


@@ -3331,6 +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)


@@ -3368,6 +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)


@@ -3392,6 +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)


@@ -3405,13 +3383,14 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
                   int d = *sp & 0x03;
 
                   *sp = (png_byte)(
                   int d = *sp & 0x03;
 
                   *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) ));
+                      ((((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;


@@ -3421,10 +3400,11 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
                   int lsb = *sp & 0x0f;
 
                   *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
                   int lsb = *sp & 0x0f;
 
                   *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)

-                          | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
+                      | (((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;


@@ -3434,6 +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;


@@ -3452,24 +3433,22 @@ png_do_gamma(png_row_infop row_info, png_bytep row,
 }
 #endif
 
 }
 #endif
 

-#if defined(PNG_READ_EXPAND_SUPPORTED)
+#ifdef PNG_READ_EXPAND_SUPPORTED

 /* Expands a palette row to an RGB or RGBA row depending
  * upon whether you supply trans and num_trans.
  */
 void /* PRIVATE */
 png_do_expand_palette(png_row_infop row_info, png_bytep row,
 /* Expands a palette row to an RGB or RGBA row depending
  * upon whether you supply trans and num_trans.
  */
 void /* PRIVATE */
 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)


@@ -3499,6 +3478,7 @@ 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);
             case 2:
             {
                sp = row + (png_size_t)((row_width - 1) >> 2);


@@ -3520,6 +3500,7 @@ 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);
             case 4:
             {
                sp = row + (png_size_t)((row_width - 1) >> 1);


@@ -3550,7 +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;


@@ -3560,7 +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;


@@ -3584,6 +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;


@@ -3596,8 +3578,8 @@ 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 /* PRIVATE */
 png_do_expand(png_row_infop row_info, png_bytep row,
  */
 void /* PRIVATE */
 png_do_expand(png_row_infop row_info, png_bytep row,


@@ -3608,10 +3590,8 @@ 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)
       {


@@ -3623,7 +3603,7 @@ png_do_expand(png_row_infop row_info, png_bytep row,
             {
                case 1:
                {
             {
                case 1:
                {

-                  gray = (png_uint_16)(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;
                   shift = 7 - (int)((row_width + 7) & 0x07);
                   sp = row + (png_size_t)((row_width - 1) >> 3);
                   dp = row + (png_size_t)row_width - 1;
                   shift = 7 - (int)((row_width + 7) & 0x07);


@@ -3645,9 +3625,10 @@ png_do_expand(png_row_infop row_info, png_bytep row,
                   }
                   break;
                }
                   }
                   break;
                }

+

                case 2:
                {
                case 2:
                {

-                  gray = (png_uint_16)(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;
                   shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
                   sp = row + (png_size_t)((row_width - 1) >> 2);
                   dp = row + (png_size_t)row_width - 1;
                   shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);


@@ -3668,9 +3649,10 @@ png_do_expand(png_row_infop row_info, png_bytep row,
                   }
                   break;
                }
                   }
                   break;
                }

+

                case 4:
                {
                case 4:
                {

-                  gray = (png_uint_16)(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;
                   shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
                   sp = row + (png_size_t)((row_width - 1) >> 1);
                   dp = row + (png_size_t)row_width - 1;
                   shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);


@@ -3691,6 +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;


@@ -3700,6 +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++)


@@ -3711,14 +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;


@@ -3732,24 +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;


@@ -3760,16 +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;


@@ -3790,26 +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)
+#ifdef PNG_READ_QUANTIZE_SUPPORTED

 void /* PRIVATE */
 void /* PRIVATE */

-png_do_dither(png_row_infop row_info, png_bytep row,
-    png_bytep palette_lookup, png_bytep dither_lookup)
+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)


@@ -3823,29 +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)


@@ -3860,30 +3850,29 @@ 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];

          }
       }
    }
          }
       }
    }


@@ -3891,238 +3880,272 @@ png_do_dither(png_row_infop row_info, png_bytep row,
 #endif
 
 #ifdef PNG_FLOATING_POINT_SUPPORTED
 #endif
 
 #ifdef PNG_FLOATING_POINT_SUPPORTED

-#if defined(PNG_READ_GAMMA_SUPPORTED)
-static int png_gamma_shift[] =
-   {0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0};
+#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 /* PRIVATE */
 void /* PRIVATE */

-png_build_gamma_table(png_structp png_ptr)
+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);
+        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 */
+        if (png_ptr->screen_gamma > 0.000001)
+           g = 1.0 / png_ptr->screen_gamma;

 
 

-         for (i = 0; i < 256; i++)
-         {
-            png_ptr->gamma_from_1[i] = (png_byte)(pow((double)i / 255.0,
-               g) * 255.0 + .5);
+        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);
+        g = 1.0 / (png_ptr->gamma);

 
 

-         png_ptr->gamma_16_to_1 = (png_uint_16pp)png_malloc(png_ptr,
-            (png_uint_32)(num * sizeof (png_uint_16p )));
+        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 * sizeof (png_uint_16)));
+        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);
-            }
-         }
+           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 */
+        if (png_ptr->screen_gamma > 0.000001)
+           g = 1.0 / png_ptr->screen_gamma;

 
 

-         png_ptr->gamma_16_from_1 = (png_uint_16pp)png_malloc(png_ptr,
-            (png_uint_32)(num * sizeof (png_uint_16p)));
+        else
+           g = png_ptr->gamma;   /* Probably doing rgb_to_gray */

 
 

-         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)));
+        png_ptr->gamma_16_from_1 = (png_uint_16pp)png_calloc(png_ptr,
+           (png_uint_32)(num * png_sizeof(png_uint_16p)));

 
 

-            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; 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 /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */

-   }
- }
+  }

 }
 #endif
 /* To do: install integer version of png_build_gamma_table here */
 #endif
 
 }
 #endif
 /* To do: install integer version of png_build_gamma_table here */
 #endif
 

-#if defined(PNG_MNG_FEATURES_SUPPORTED)
-/* undoes intrapixel differencing  */
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+/* Undoes intrapixel differencing  */

 void /* PRIVATE */
 png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
 {
 void /* PRIVATE */
 png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
 {

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

    if (
    if (

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

        (row_info->color_type & PNG_COLOR_MASK_COLOR))
    {
       int bytes_per_pixel;
        (row_info->color_type & PNG_COLOR_MASK_COLOR))
    {
       int bytes_per_pixel;


@@ -4134,8 +4157,10 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
 
          if (row_info->color_type == PNG_COLOR_TYPE_RGB)
             bytes_per_pixel = 3;
 
          if (row_info->color_type == PNG_COLOR_TYPE_RGB)
             bytes_per_pixel = 3;

+

          else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
             bytes_per_pixel = 4;
          else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
             bytes_per_pixel = 4;

+

          else
             return;
 
          else
             return;
 


@@ -4152,24 +4177,27 @@ png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
 
          if (row_info->color_type == PNG_COLOR_TYPE_RGB)
             bytes_per_pixel = 6;
 
          if (row_info->color_type == PNG_COLOR_TYPE_RGB)
             bytes_per_pixel = 6;

+

          else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
             bytes_per_pixel = 8;
          else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
             bytes_per_pixel = 8;

+

          else
             return;
 
          for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
          {
          else
             return;
 
          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=(65536+s0+s1)&0xffff;
-            png_uint_32 blue=(65536+s2+s1)&0xffff;
-            *(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);
+            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_MNG_FEATURES_SUPPORTED */
          }
       }
    }
 }
 #endif /* PNG_MNG_FEATURES_SUPPORTED */

+#endif /* PNG_READ_SUPPORTED */