Cleanup

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

diff --git a/src/png/example.c b/src/png/example.c
index 088aad3a764d5c073fc01b58c3286cfb636f5c23..7956cf7abd192393166724577b11d1edf72fba01 100644 (file)
--- a/src/png/example.c
+++ b/src/png/example.c
@@ -1,20 +1,33 @@
 
 

+#if 0 /* in case someone actually tries to compile this */
+

 /* example.c - an example of using libpng */
 
 /* This is an example of how to use libpng to read and write PNG files.
  * The file libpng.txt is much more verbose then this.  If you have not
  * read it, do so first.  This was designed to be a starting point of an
 /* example.c - an example of using libpng */
 
 /* This is an example of how to use libpng to read and write PNG files.
  * The file libpng.txt is much more verbose then this.  If you have not
  * read it, do so first.  This was designed to be a starting point of an

- * implementation.  This is not officially part of libpng, and therefore
- * does not require a copyright notice.
+ * implementation.  This is not officially part of libpng, is hereby placed
+ * in the public domain, and therefore does not require a copyright notice.

  *
  * This file does not currently compile, because it is missing certain
  * parts, like allocating memory to hold an image.  You will have to
  * supply these parts to get it to compile.  For an example of a minimal
  *
  * This file does not currently compile, because it is missing certain
  * parts, like allocating memory to hold an image.  You will have to
  * supply these parts to get it to compile.  For an example of a minimal

- * working PNG reader/writer, see pngtest.c, included in this distribution.
+ * working PNG reader/writer, see pngtest.c, included in this distribution;
+ * see also the programs in the contrib directory.

  */
 
 #include "png.h"
 
  */
 
 #include "png.h"
 

+ /* The png_jmpbuf() macro, used in error handling, became available in
+  * libpng version 1.0.6.  If you want to be able to run your code with older
+  * versions of libpng, you must define the macro yourself (but only if it
+  * is not already defined by libpng!).
+  */
+
+#ifndef png_jmpbuf
+#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
+#endif
+

 /* Check to see if a file is a PNG file using png_sig_cmp().  png_sig_cmp()
  * returns zero if the image is a PNG and nonzero if it isn't a PNG.
  *
 /* Check to see if a file is a PNG file using png_sig_cmp().  png_sig_cmp()
  * returns zero if the image is a PNG and nonzero if it isn't a PNG.
  *


@@ -41,7 +54,7 @@ int check_if_png(char *file_name, FILE **fp)
    char buf[PNG_BYTES_TO_CHECK];
 
    /* Open the prospective PNG file. */
    char buf[PNG_BYTES_TO_CHECK];
 
    /* Open the prospective PNG file. */

-   if ((*fp = fopen(file_name, "rb")) != NULL);
+   if ((*fp = fopen(file_name, "rb")) == NULL)

       return 0;
 
    /* Read in some of the signature bytes */
       return 0;
 
    /* Read in some of the signature bytes */


@@ -71,7 +84,7 @@ void read_png(char *file_name)  /* We need to open the file */
    FILE *fp;
 
    if ((fp = fopen(file_name, "rb")) == NULL)
    FILE *fp;
 
    if ((fp = fopen(file_name, "rb")) == NULL)

-      return;
+      return (ERROR);

 #else no_open_file /* prototype 2 */
 void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
 {
 #else no_open_file /* prototype 2 */
 void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
 {


@@ -93,7 +106,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
    if (png_ptr == NULL)
    {
       fclose(fp);
    if (png_ptr == NULL)
    {
       fclose(fp);

-      return;
+      return (ERROR);

    }
 
    /* Allocate/initialize the memory for image information.  REQUIRED. */
    }
 
    /* Allocate/initialize the memory for image information.  REQUIRED. */


@@ -101,21 +114,22 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
    if (info_ptr == NULL)
    {
       fclose(fp);
    if (info_ptr == NULL)
    {
       fclose(fp);

-      png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
-      return;
+      png_destroy_read_struct(&png_ptr, png_infopp_NULL, png_infopp_NULL);
+      return (ERROR);

    }
 
    /* Set error handling if you are using the setjmp/longjmp method (this is
     * the normal method of doing things with libpng).  REQUIRED unless you
     * set up your own error handlers in the png_create_read_struct() earlier.
     */
    }
 
    /* Set error handling if you are using the setjmp/longjmp method (this is
     * the normal method of doing things with libpng).  REQUIRED unless you
     * set up your own error handlers in the png_create_read_struct() earlier.
     */

-   if (setjmp(png_ptr->jmpbuf))
+
+   if (setjmp(png_jmpbuf(png_ptr)))

    {
       /* Free all of the memory associated with the png_ptr and info_ptr */
    {
       /* Free all of the memory associated with the png_ptr and info_ptr */

-      png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
+      png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL);

       fclose(fp);
       /* If we get here, we had a problem reading the file */
       fclose(fp);
       /* If we get here, we had a problem reading the file */

-      return;
+      return (ERROR);

    }
 
    /* One of the following I/O initialization methods is REQUIRED */
    }
 
    /* One of the following I/O initialization methods is REQUIRED */


@@ -134,24 +148,37 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
    /* If we have already read some of the signature */
    png_set_sig_bytes(png_ptr, sig_read);
 
    /* If we have already read some of the signature */
    png_set_sig_bytes(png_ptr, sig_read);
 

+#ifdef hilevel
+   /*
+    * If you have enough memory to read in the entire image at once,
+    * and you need to specify only transforms that can be controlled
+    * with one of the PNG_TRANSFORM_* bits (this presently excludes
+    * dithering, filling, setting background, and doing gamma
+    * adjustment), then you can read the entire image (including
+    * pixels) into the info structure with this call:
+    */
+   png_read_png(png_ptr, info_ptr, png_transforms, png_voidp_NULL);
+#else
+   /* OK, you're doing it the hard way, with the lower-level functions */
+

    /* The call to png_read_info() gives us all of the information from the
     * PNG file before the first IDAT (image data chunk).  REQUIRED
     */
    png_read_info(png_ptr, info_ptr);
 
    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
    /* The call to png_read_info() gives us all of the information from the
     * PNG file before the first IDAT (image data chunk).  REQUIRED
     */
    png_read_info(png_ptr, info_ptr);
 
    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,

-       &interlace_type, NULL, NULL);
+       &interlace_type, int_p_NULL, int_p_NULL);

 
 

-/**** Set up the data transformations you want.  Note that these are all
- **** optional.  Only call them if you want/need them.  Many of the
- **** transformations only work on specific types of images, and many
- **** are mutually exclusive.
- ****/
+/* Set up the data transformations you want.  Note that these are all
+ * optional.  Only call them if you want/need them.  Many of the
+ * transformations only work on specific types of images, and many
+ * are mutually exclusive.
+ */

 
    /* tell libpng to strip 16 bit/color files down to 8 bits/color */
    png_set_strip_16(png_ptr);
 
 
    /* tell libpng to strip 16 bit/color files down to 8 bits/color */
    png_set_strip_16(png_ptr);
 

-   /* Strip alpha bytes from the input data without combining with th
+   /* Strip alpha bytes from the input data without combining with the

     * background (not recommended).
     */
    png_set_strip_alpha(png_ptr);
     * background (not recommended).
     */
    png_set_strip_alpha(png_ptr);


@@ -167,17 +194,17 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
 
    /* Expand paletted colors into true RGB triplets */
    if (color_type == PNG_COLOR_TYPE_PALETTE)
 
    /* Expand paletted colors into true RGB triplets */
    if (color_type == PNG_COLOR_TYPE_PALETTE)

-      png_set_expand(png_ptr);
+      png_set_palette_rgb(png_ptr);

 
    /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
 
    /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)

-      png_set_expand(png_ptr);
+      png_set_gray_1_2_4_to_8(png_ptr);

 
    /* Expand paletted or RGB images with transparency to full alpha channels
     * so the data will be available as RGBA quartets.
     */
    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
 
    /* Expand paletted or RGB images with transparency to full alpha channels
     * so the data will be available as RGBA quartets.
     */
    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))

-      png_set_expand(png_ptr);
+      png_set_tRNS_to_alpha(png_ptr);

 
    /* Set the background color to draw transparent and alpha images over.
     * It is possible to set the red, green, and blue components directly
 
    /* Set the background color to draw transparent and alpha images over.
     * It is possible to set the red, green, and blue components directly


@@ -197,7 +224,8 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
 
    /* Some suggestions as to how to get a screen gamma value */
 
 
    /* Some suggestions as to how to get a screen gamma value */
 

-   /* Note that screen gamma is (display_gamma/viewing_gamma) */
+   /* Note that screen gamma is the display_exponent, which includes
+    * the CRT_exponent and any correction for viewing conditions */

    if (/* We have a user-defined screen gamma value */)
    {
       screen_gamma = user-defined screen_gamma;
    if (/* We have a user-defined screen gamma value */)
    {
       screen_gamma = user-defined screen_gamma;


@@ -215,7 +243,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
       screen_gamma = 1.7 or 1.0;  /* A good guess for Mac systems */
    }
 
       screen_gamma = 1.7 or 1.0;  /* A good guess for Mac systems */
    }
 

-   /* Tell libpng to handle the gamma conversion for you.  The second call
+   /* Tell libpng to handle the gamma conversion for you.  The final call

     * is a good guess for PC generated images, but it should be configurable
     * by the user at run time by the user.  It is strongly suggested that
     * your application support gamma correction.
     * is a good guess for PC generated images, but it should be configurable
     * by the user at run time by the user.  It is strongly suggested that
     * your application support gamma correction.


@@ -224,7 +252,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
    int intent;
 
    if (png_get_sRGB(png_ptr, info_ptr, &intent))
    int intent;
 
    if (png_get_sRGB(png_ptr, info_ptr, &intent))

-      png_set_sRGB(png_ptr, intent, 0);
+      png_set_gamma(png_ptr, screen_gamma, 0.45455);

    else
    {
       double image_gamma;
    else
    {
       double image_gamma;


@@ -239,7 +267,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
     */
    if (color_type & PNG_COLOR_MASK_COLOR)
    {
     */
    if (color_type & PNG_COLOR_MASK_COLOR)
    {

-      png_uint_32 num_palette;
+      int num_palette;

       png_colorp palette;
 
       /* This reduces the image to the application supplied palette */
       png_colorp palette;
 
       /* This reduces the image to the application supplied palette */


@@ -249,12 +277,12 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
          png_color std_color_cube[MAX_SCREEN_COLORS];
 
          png_set_dither(png_ptr, std_color_cube, MAX_SCREEN_COLORS,
          png_color std_color_cube[MAX_SCREEN_COLORS];
 
          png_set_dither(png_ptr, std_color_cube, MAX_SCREEN_COLORS,

-            MAX_SCREEN_COLORS, NULL, 0);
+            MAX_SCREEN_COLORS, png_uint_16p_NULL, 0);

       }
       /* This reduces the image to the palette supplied in the file */
       else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
       {
       }
       /* This reduces the image to the palette supplied in the file */
       else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
       {

-         png_color16p histogram;
+         png_uint_16p histogram = NULL;

 
          png_get_hIST(png_ptr, info_ptr, &histogram);
 
 
          png_get_hIST(png_ptr, info_ptr, &histogram);
 


@@ -263,7 +291,7 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
       }
    }
 
       }
    }
 

-   /* invert monocrome files to have 0 as white and 1 as black */
+   /* invert monochrome files to have 0 as white and 1 as black */

    png_set_invert_mono(png_ptr);
 
    /* If you want to shift the pixel values from the range [0,255] or
    png_set_invert_mono(png_ptr);
 
    /* If you want to shift the pixel values from the range [0,255] or


@@ -272,14 +300,15 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
     */
    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
    {
     */
    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
    {

-      png_color8p sig_bit;
+      png_color_8p sig_bit;

 
       png_get_sBIT(png_ptr, info_ptr, &sig_bit);
       png_set_shift(png_ptr, sig_bit);
    }
 
    /* flip the RGB pixels to BGR (or RGBA to BGRA) */
 
       png_get_sBIT(png_ptr, info_ptr, &sig_bit);
       png_set_shift(png_ptr, sig_bit);
    }
 
    /* flip the RGB pixels to BGR (or RGBA to BGRA) */

-   png_set_bgr(png_ptr);
+   if (color_type & PNG_COLOR_MASK_COLOR)
+      png_set_bgr(png_ptr);

 
    /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
    png_set_swap_alpha(png_ptr);
 
    /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
    png_set_swap_alpha(png_ptr);


@@ -309,7 +338,8 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
 
    for (row = 0; row < height; row++)
    {
 
    for (row = 0; row < height; row++)
    {

-      row_pointers[row] = malloc(png_get_rowbytes(png_ptr, info_ptr));
+      row_pointers[row] = png_malloc(png_ptr, png_get_rowbytes(png_ptr,
+         info_ptr));

    }
 
    /* Now it's time to read the image.  One of these methods is REQUIRED */
    }
 
    /* Now it's time to read the image.  One of these methods is REQUIRED */


@@ -324,18 +354,18 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
 #ifdef single /* Read the image a single row at a time */
       for (y = 0; y < height; y++)
       {
 #ifdef single /* Read the image a single row at a time */
       for (y = 0; y < height; y++)
       {

-         png_read_rows(png_ptr, &row_pointers[y], NULL, 1);
+         png_read_rows(png_ptr, &row_pointers[y], png_bytepp_NULL, 1);

       }
 
 #else no_single /* Read the image several rows at a time */
       for (y = 0; y < height; y += number_of_rows)
       {
 #ifdef sparkle /* Read the image using the "sparkle" effect. */
       }
 
 #else no_single /* Read the image several rows at a time */
       for (y = 0; y < height; y += number_of_rows)
       {
 #ifdef sparkle /* Read the image using the "sparkle" effect. */

-         png_read_rows(png_ptr, &row_pointers[y], NULL, number_of_rows);
-
-         png_read_rows(png_ptr, NULL, row_pointers[y], number_of_rows);
+         png_read_rows(png_ptr, &row_pointers[y], png_bytepp_NULL,
+            number_of_rows);

 #else no_sparkle /* Read the image using the "rectangle" effect */
 #else no_sparkle /* Read the image using the "rectangle" effect */

-         png_read_rows(png_ptr, NULL, &row_pointers[y], number_of_rows);
+         png_read_rows(png_ptr, png_bytepp_NULL, &row_pointers[y],
+            number_of_rows);

 #endif no_sparkle /* use only one of these two methods */
       }
 
 #endif no_sparkle /* use only one of these two methods */
       }
 


@@ -347,15 +377,18 @@ void read_png(FILE *fp, unsigned int sig_read)  /* file is already open */
 
    /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
    png_read_end(png_ptr, info_ptr);
 
    /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
    png_read_end(png_ptr, info_ptr);

+#endif hilevel
+
+   /* At this point you have read the entire image */

 
    /* clean up after the read, and free any memory allocated - REQUIRED */
 
    /* clean up after the read, and free any memory allocated - REQUIRED */

-   png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
+   png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL);

 
    /* close the file */
    fclose(fp);
 
    /* that's it */
 
    /* close the file */
    fclose(fp);
 
    /* that's it */

-   return;
+   return (OK);

 }
 
 /* progressively read a file */
 }
 
 /* progressively read a file */


@@ -375,21 +408,21 @@ initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr)
    if (*png_ptr == NULL)
    {
       *info_ptr = NULL;
    if (*png_ptr == NULL)
    {
       *info_ptr = NULL;

-      return ERROR;
+      return (ERROR);

    }
 
    *info_ptr = png_create_info_struct(png_ptr);
 
    if (*info_ptr == NULL)
    {
    }
 
    *info_ptr = png_create_info_struct(png_ptr);
 
    if (*info_ptr == NULL)
    {

-      png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL);
-      return ERROR;
+      png_destroy_read_struct(png_ptr, info_ptr, png_infopp_NULL);
+      return (ERROR);

    }
 
    }
 

-   if (setjmp((*png_ptr)->jmpbuf))
+   if (setjmp(png_jmpbuf((*png_ptr))))

    {
    {

-      png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL);
-      return ERROR;
+      png_destroy_read_struct(png_ptr, info_ptr, png_infopp_NULL);
+      return (ERROR);

    }
 
    /* This one's new.  You will need to provide all three
    }
 
    /* This one's new.  You will need to provide all three


@@ -407,18 +440,18 @@ initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr)
    png_set_progressive_read_fn(*png_ptr, (void *)stream_data,
       info_callback, row_callback, end_callback);
 
    png_set_progressive_read_fn(*png_ptr, (void *)stream_data,
       info_callback, row_callback, end_callback);
 

-   return OK;
+   return (OK);

 }
 
 int
 process_data(png_structp *png_ptr, png_infop *info_ptr,
    png_bytep buffer, png_uint_32 length)
 {
 }
 
 int
 process_data(png_structp *png_ptr, png_infop *info_ptr,
    png_bytep buffer, png_uint_32 length)
 {

-   if (setjmp((*png_ptr)->jmpbuf))
+   if (setjmp(png_jmpbuf((*png_ptr))))

    {
       /* Free the png_ptr and info_ptr memory on error */
    {
       /* Free the png_ptr and info_ptr memory on error */

-      png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL);
-      return ERROR;
+      png_destroy_read_struct(png_ptr, info_ptr, png_infopp_NULL);
+      return (ERROR);

    }
 
    /* This one's new also.  Simply give it chunks of data as
    }
 
    /* This one's new also.  Simply give it chunks of data as


@@ -432,7 +465,7 @@ process_data(png_structp *png_ptr, png_infop *info_ptr,
     * callback, if you aren't already displaying them there.
     */
    png_process_data(*png_ptr, *info_ptr, buffer, length);
     * callback, if you aren't already displaying them there.
     */
    png_process_data(*png_ptr, *info_ptr, buffer, length);

-   return OK;
+   return (OK);

 }
 
 info_callback(png_structp png_ptr, png_infop info)
 }
 
 info_callback(png_structp png_ptr, png_infop info)


@@ -449,21 +482,47 @@ info_callback(png_structp png_ptr, png_infop info)
 row_callback(png_structp png_ptr, png_bytep new_row,
    png_uint_32 row_num, int pass)
 {
 row_callback(png_structp png_ptr, png_bytep new_row,
    png_uint_32 row_num, int pass)
 {

-/* this function is called for every row in the image.  If the
- * image is interlacing, and you turned on the interlace handler,
+/*
+ * This function is called for every row in the image.  If the
+ * image is interlaced, and you turned on the interlace handler,

  * this function will be called for every row in every pass.
  * this function will be called for every row in every pass.

- * Some of these rows will not be changed from the previous pass.
- * When the row is not changed, the new_row variable will be NULL.
+ *
+ * In this function you will receive a pointer to new row data from
+ * libpng called new_row that is to replace a corresponding row (of
+ * the same data format) in a buffer allocated by your application.
+ * 
+ * The new row data pointer new_row may be NULL, indicating there is
+ * no new data to be replaced (in cases of interlace loading).
+ * 
+ * If new_row is not NULL then you need to call
+ * png_progressive_combine_row() to replace the corresponding row as
+ * shown below:
+ */
+   /* Check if row_num is in bounds. */
+   if((row_num >= 0) && (row_num < height))
+   {
+     /* Get pointer to corresponding row in our
+      * PNG read buffer.
+      */
+     png_bytep old_row = ((png_bytep *)our_data)[row_num];
+
+     /* If both rows are allocated then copy the new row
+      * data to the corresponding row data.
+      */
+     if((old_row != NULL) && (new_row != NULL))
+     png_progressive_combine_row(png_ptr, old_row, new_row);
+   }
+/*

  * The rows and passes are called in order, so you don't really
  * need the row_num and pass, but I'm supplying them because it
  * may make your life easier.
  *
  * For the non-NULL rows of interlaced images, you must call
  * The rows and passes are called in order, so you don't really
  * need the row_num and pass, but I'm supplying them because it
  * may make your life easier.
  *
  * For the non-NULL rows of interlaced images, you must call

- * png_progressive_combine_row() passing in the row and the
- * old row.  You can call this function for NULL rows (it will
- * just return) and for non-interlaced images (it just does the
- * memcpy for you) if it will make the code easier.  Thus, you
- * can just do this for all cases:
+ * png_progressive_combine_row() passing in the new row and the
+ * old row, as demonstrated above.  You can call this function for
+ * NULL rows (it will just return) and for non-interlaced images
+ * (it just does the png_memcpy for you) if it will make the code
+ * easier.  Thus, you can just do this for all cases:

  */
 
    png_progressive_combine_row(png_ptr, old_row, new_row);
  */
 
    png_progressive_combine_row(png_ptr, old_row, new_row);


@@ -472,8 +531,8 @@ row_callback(png_structp png_ptr, png_bytep new_row,
  * that the first pass (pass == 0 really) will completely cover
  * the old row, so the rows do not have to be initialized.  After
  * the first pass (and only for interlaced images), you will have
  * that the first pass (pass == 0 really) will completely cover
  * the old row, so the rows do not have to be initialized.  After
  * the first pass (and only for interlaced images), you will have

- * to pass the current row, and the function will combine the
- * old row and the new row.
+ * to pass the current row as new_row, and the function will combine
+ * the old row and the new row.

  */
 }
 
  */
 }
 


@@ -496,11 +555,12 @@ void write_png(char *file_name /* , ... other image information ... */)
    FILE *fp;
    png_structp png_ptr;
    png_infop info_ptr;
    FILE *fp;
    png_structp png_ptr;
    png_infop info_ptr;

+   png_colorp palette;

 
    /* open the file */
    fp = fopen(file_name, "wb");
    if (fp == NULL)
 
    /* open the file */
    fp = fopen(file_name, "wb");
    if (fp == NULL)

-      return;
+      return (ERROR);

 
    /* Create and initialize the png_struct with the desired error handler
     * functions.  If you want to use the default stderr and longjump method,
 
    /* Create and initialize the png_struct with the desired error handler
     * functions.  If you want to use the default stderr and longjump method,


@@ -514,7 +574,7 @@ void write_png(char *file_name /* , ... other image information ... */)
    if (png_ptr == NULL)
    {
       fclose(fp);
    if (png_ptr == NULL)
    {
       fclose(fp);

-      return;
+      return (ERROR);

    }
 
    /* Allocate/initialize the image information data.  REQUIRED */
    }
 
    /* Allocate/initialize the image information data.  REQUIRED */


@@ -522,19 +582,19 @@ void write_png(char *file_name /* , ... other image information ... */)
    if (info_ptr == NULL)
    {
       fclose(fp);
    if (info_ptr == NULL)
    {
       fclose(fp);

-      png_destroy_write_struct(&png_ptr,  (png_infopp)NULL);
-      return;
+      png_destroy_write_struct(&png_ptr,  png_infopp_NULL);
+      return (ERROR);

    }
 
    /* Set error handling.  REQUIRED if you aren't supplying your own
    }
 
    /* Set error handling.  REQUIRED if you aren't supplying your own

-    * error hadnling functions in the png_create_write_struct() call.
+    * error handling functions in the png_create_write_struct() call.

     */
     */

-   if (setjmp(png_ptr->jmpbuf))
+   if (setjmp(png_jmpbuf(png_ptr)))

    {
       /* If we get here, we had a problem reading the file */
       fclose(fp);
    {
       /* If we get here, we had a problem reading the file */
       fclose(fp);

-      png_destroy_write_struct(&png_ptr,  (png_infopp)NULL);
-      return;
+      png_destroy_write_struct(&png_ptr, &info_ptr);
+      return (ERROR);

    }
 
    /* One of the following I/O initialization functions is REQUIRED */
    }
 
    /* One of the following I/O initialization functions is REQUIRED */


@@ -549,6 +609,15 @@ void write_png(char *file_name /* , ... other image information ... */)
    /* where user_io_ptr is a structure you want available to the callbacks */
 #endif no_streams /* only use one initialization method */
 
    /* where user_io_ptr is a structure you want available to the callbacks */
 #endif no_streams /* only use one initialization method */
 

+#ifdef hilevel
+   /* This is the easy way.  Use it if you already have all the
+    * image info living info in the structure.  You could "|" many
+    * PNG_TRANSFORM flags into the png_transforms integer here.
+    */
+   png_write_png(png_ptr, info_ptr, png_transforms, png_voidp_NULL);
+#else
+   /* This is the hard way */
+

    /* Set the image information here.  Width and height are up to 2^31,
     * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on
     * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY,
    /* Set the image information here.  Width and height are up to 2^31,
     * bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on
     * the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY,


@@ -561,9 +630,13 @@ void write_png(char *file_name /* , ... other image information ... */)
       PNG_INTERLACE_????, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 
    /* set the palette if there is one.  REQUIRED for indexed-color images */
       PNG_INTERLACE_????, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
 
    /* set the palette if there is one.  REQUIRED for indexed-color images */

-   palette = (png_colorp)png_malloc(png_ptr, 256 * sizeof (png_color));
+   palette = (png_colorp)png_malloc(png_ptr, PNG_MAX_PALETTE_LENGTH
+             * sizeof (png_color));

    /* ... set palette colors ... */
    /* ... set palette colors ... */

-   png_set_PLTE(png_ptr, info_ptr, palette, 256);
+   png_set_PLTE(png_ptr, info_ptr, palette, PNG_MAX_PALETTE_LENGTH);
+   /* You must not free palette here, because png_set_PLTE only makes a link to
+      the palette that you malloced.  Wait until you are about to destroy
+      the png structure. */

 
    /* optional significant bit chunk */
    /* if we are dealing with a grayscale image then */
 
    /* optional significant bit chunk */
    /* if we are dealing with a grayscale image then */


@@ -592,15 +665,31 @@ void write_png(char *file_name /* , ... other image information ... */)
    text_ptr[2].key = "Description";
    text_ptr[2].text = "<long text>";
    text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;
    text_ptr[2].key = "Description";
    text_ptr[2].text = "<long text>";
    text_ptr[2].compression = PNG_TEXT_COMPRESSION_zTXt;

+#ifdef PNG_iTXt_SUPPORTED
+   text_ptr[0].lang = NULL;
+   text_ptr[1].lang = NULL;
+   text_ptr[2].lang = NULL;
+#endif

    png_set_text(png_ptr, info_ptr, text_ptr, 3);
 
    /* other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs, */
    png_set_text(png_ptr, info_ptr, text_ptr, 3);
 
    /* other optional chunks like cHRM, bKGD, tRNS, tIME, oFFs, pHYs, */

-   /* note that if sRGB is present the cHRM chunk must be ignored
+   /* note that if sRGB is present the gAMA and cHRM chunks must be ignored

     * on read and must be written in accordance with the sRGB profile */
 
    /* Write the file header information.  REQUIRED */
    png_write_info(png_ptr, info_ptr);
 
     * on read and must be written in accordance with the sRGB profile */
 
    /* Write the file header information.  REQUIRED */
    png_write_info(png_ptr, info_ptr);
 

+   /* If you want, you can write the info in two steps, in case you need to
+    * write your private chunk ahead of PLTE:
+    *
+    *   png_write_info_before_PLTE(write_ptr, write_info_ptr);
+    *   write_my_chunk();
+    *   png_write_info(png_ptr, info_ptr);
+    *
+    * However, given the level of known- and unknown-chunk support in 1.1.0
+    * and up, this should no longer be necessary.
+    */
+

    /* Once we write out the header, the compression type on the text
     * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
     * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again
    /* Once we write out the header, the compression type on the text
     * chunks gets changed to PNG_TEXT_COMPRESSION_NONE_WR or
     * PNG_TEXT_COMPRESSION_zTXt_WR, so it doesn't get written out again


@@ -611,7 +700,7 @@ void write_png(char *file_name /* , ... other image information ... */)
     * all optional.  Only call them if you want them.
     */
 
     * all optional.  Only call them if you want them.
     */
 

-   /* invert monocrome pixels */
+   /* invert monochrome pixels */

    png_set_invert_mono(png_ptr);
 
    /* Shift the pixels up to a legal bit depth and fill in
    png_set_invert_mono(png_ptr);
 
    /* Shift the pixels up to a legal bit depth and fill in


@@ -650,10 +739,10 @@ void write_png(char *file_name /* , ... other image information ... */)
     * use the first method if you aren't handling interlacing yourself.
     */
    png_uint_32 k, height, width;
     * use the first method if you aren't handling interlacing yourself.
     */
    png_uint_32 k, height, width;

-   png_byte image[height][width];
+   png_byte image[height][width*bytes_per_pixel];

    png_bytep row_pointers[height];
    for (k = 0; k < height; k++)
    png_bytep row_pointers[height];
    for (k = 0; k < height; k++)

-     row_pointers[k] = image + k*width;
+     row_pointers[k] = image + k*width*bytes_per_pixel;

 
    /* One of the following output methods is REQUIRED */
 #ifdef entire /* write out the entire image data in one call */
 
    /* One of the following output methods is REQUIRED */
 #ifdef entire /* write out the entire image data in one call */


@@ -679,24 +768,37 @@ void write_png(char *file_name /* , ... other image information ... */)
 #endif no_entire /* use only one output method */
 
    /* You can write optional chunks like tEXt, zTXt, and tIME at the end
 #endif no_entire /* use only one output method */
 
    /* You can write optional chunks like tEXt, zTXt, and tIME at the end

-    * as well.
+    * as well.  Shouldn't be necessary in 1.1.0 and up as all the public
+    * chunks are supported and you can use png_set_unknown_chunks() to
+    * register unknown chunks into the info structure to be written out.

     */
 
    /* It is REQUIRED to call this to finish writing the rest of the file */
    png_write_end(png_ptr, info_ptr);
     */
 
    /* It is REQUIRED to call this to finish writing the rest of the file */
    png_write_end(png_ptr, info_ptr);

-
-   /* if you malloced the palette, free it here */
-   free(info_ptr->palette);
-
-   /* if you allocated any text comments, free them here */
+#endif hilevel
+
+   /* If you png_malloced a palette, free it here (don't free info_ptr->palette,
+      as recommended in versions 1.0.5m and earlier of this example; if
+      libpng mallocs info_ptr->palette, libpng will free it).  If you
+      allocated it with malloc() instead of png_malloc(), use free() instead
+      of png_free(). */
+   png_free(png_ptr, palette);
+   palette=NULL;
+
+   /* Similarly, if you png_malloced any data that you passed in with
+      png_set_something(), such as a hist or trans array, free it here,
+      when you can be sure that libpng is through with it. */
+   png_free(png_ptr, trans);
+   trans=NULL;

 
    /* clean up after the write, and free any memory allocated */
 
    /* clean up after the write, and free any memory allocated */

-   png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
+   png_destroy_write_struct(&png_ptr, &info_ptr);

 
    /* close the file */
    fclose(fp);
 
    /* that's it */
 
    /* close the file */
    fclose(fp);
 
    /* that's it */

-   return;
+   return (OK);

 }
 
 }
 

+#endif /* if 0 */