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Imported from libpng-0.81.tar

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This commit is contained in:
Guy Schalnat
1995-09-26 05:22:39 -05:00
committed by Glenn Randers-Pehrson
parent 0d5805822f
commit 51f0eb4584
26 changed files with 2124 additions and 1750 deletions
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63
example.c
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@@ -6,6 +6,10 @@
designed to be a starting point of an implementation.
This is not officially part of libpng, 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.
*/
#include <png.h>
@@ -81,15 +85,11 @@ void read_png(char *file_name)
/* read the file information */
png_read_info(png_ptr, info_ptr);
/* allocate the memory to hold the image using the fields
of png_info. */
/* set up the transformations you want. Note that these are
all optional. Only call them if you want them */
/* expand paletted colors into true rgb */
if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
info_ptr->bit_depth < 8)
if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
png_set_expand(png_ptr);
/* expand grayscale images to the full 8 bits */
@@ -163,26 +163,32 @@ void read_png(char *file_name)
if (info_ptr->bit_depth == 16)
png_set_swap(png_ptr);
/* add a filler byte to store rgb files as rgbx */
/* add a filler byte to rgb files */
if (info_ptr->bit_depth == 8 &&
info_ptr->color_type == PNG_COLOR_TYPE_RGB)
png_set_rgbx(png_ptr);
png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
/* optional call to update palette with transformations */
png_start_read_image(png_ptr);
/* the easiest way to read the image */
void *row_pointers[height];
png_read_image(png_ptr, row_pointers);
/* the other way to read images - deal with interlacing */
/* turn on interlace handling */
/* turn on interlace handling if you are not using png_read_image() */
if (info_ptr->interlace_type)
number_passes = png_set_interlace_handling(png_ptr);
else
number_passes = 1;
/* optional call to update palette with transformations */
png_start_read_image(png_ptr);
/* optional call to update the info structure */
png_read_update_info(png_ptr, info_ptr);
/* allocate the memory to hold the image using the fields
of png_info. */
/* the easiest way to read the image */
png_bytef *row_pointers[height];
png_read_image(png_ptr, row_pointers);
/* the other way to read images - deal with interlacing */
for (pass = 0; pass < number_passes; pass++)
{
/* Read the image using the "sparkle" effect. */
@@ -191,7 +197,7 @@ void read_png(char *file_name)
/* If you are only reading on row at a time, this works */
for (y = 0; y < height; y++)
{
char *row_pointers = row[y];
png_bytef *row_pointers = row[y];
png_read_rows(png_ptr, &row_pointers, NULL, 1);
}
@@ -309,21 +315,22 @@ void write_png(char *file_name, ... other image information ...)
/* swap bytes of 16 bit files to most significant bit first */
png_set_swap(png_ptr);
/* get rid of filler bytes, pack rgb into 3 bytes */
png_set_rgbx(png_ptr);
/* get rid of filler bytes, pack rgb into 3 bytes. The
filler number is not used. */
png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
/* the easiest way to write the image */
void *row_pointers[height];
png_write_image(png_ptr, row_pointers);
/* the other way to write the image - deal with interlacing */
/* turn on interlace handling */
/* turn on interlace handling if you are not using png_write_image() */
if (interlacing)
number_passes = png_set_interlace_handling(png_ptr);
else
number_passes = 1;
/* the easiest way to write the image */
png_bytef *row_pointers[height];
png_write_image(png_ptr, row_pointers);
/* the other way to write the image - deal with interlacing */
for (pass = 0; pass < number_passes; pass++)
{
/* Write a few rows at a time. */
@@ -332,7 +339,7 @@ void write_png(char *file_name, ... other image information ...)
/* If you are only writing one row at a time, this works */
for (y = 0; y < height; y++)
{
char *row_pointers = row[y];
png_bytef *row_pointers = row[y];
png_write_rows(png_ptr, &row_pointers, 1);
}
}