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Imported from libpng-0.99e.tar

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This commit is contained in:
Glenn Randers-Pehrson
1998-02-28 07:00:24 -06:00
parent a357b99113
commit cbe52d8720
28 changed files with 843 additions and 694 deletions
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64
example.c
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@@ -12,7 +12,7 @@
* working PNG reader/writer, see pngtest.c, included in this distribution.
*/
#include <png.h>
#include "png.h"
/* Check to see if a file is a PNG file using png_check_sig(). Returns
* non-zero if the image is a PNG, and 0 if it isn't a PNG.
@@ -54,7 +54,7 @@ int check_if_png(char *file_name, FILE **fp)
* file, and the other where we are given an open file (possibly with
* some or all of the magic bytes read - see comments above).
*/
**** prototype 1 ****
#ifdef open_file /* prototype 1 */
void read_png(char *file_name) /* We need to open the file */
{
png_structp png_ptr;
@@ -66,14 +66,14 @@ void read_png(char *file_name) /* We need to open the file */
if ((fp = fopen(file_name, "rb")) == NULL)
return;
**** prototype 2 ****
#else no_open_file /* prototype 2 */
void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
{
png_structp png_ptr;
png_infop info_ptr;
png_uint_32 width, height;
int bit_depth, color_type, interlace_type;
**** only use one prototype! ****
#endif no_open_file /* only use one prototype! */
/* Create and initialize the png_struct with the desired error handler
* functions. If you want to use the default stderr and longjump method,
@@ -113,17 +113,17 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
}
/* One of the following I/O initialization methods is REQUIRED */
**** PNG file I/O method 1 ****
#ifdef streams /* PNG file I/O method 1 */
/* Set up the input control if you are using standard C streams */
png_init_io(png_ptr, fp);
**** PNG file I/O method 2 ****
#else no_streams /* PNG file I/O method 2 */
/* If you are using replacement read functions, instead of calling
* png_init_io() here you would call:
*/
png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn);
/* where user_io_ptr is a structure you want available to the callbacks */
**** Use only one I/O method! ****
#endif no_streams /* Use only one I/O method! */
/* If we have already read some of the signature */
png_set_sig_bytes_read(png_ptr, sig_read);
@@ -180,10 +180,10 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
* use it - you should use the (solid) application background if it has one.
*/
png_color_16 my_background, *image_background);
png_color_16 my_background, *image_background;
if (png_get_bKGD(png_ptr, info_ptr, &image_background);
png_set_background(png_ptr, image_background),
if (png_get_bKGD(png_ptr, info_ptr, &image_background))
png_set_background(png_ptr, image_background,
PNG_BACKGROUND_GAMMA_FILE, 1, 1.0);
else
png_set_background(png_ptr, &my_background,
@@ -191,7 +191,7 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
/* 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 (display_gamma/viewing_gamma) */
if (/* We have a user-defined screen gamma value */)
{
screen_gamma = user-defined screen_gamma;
@@ -217,10 +217,10 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
int intent;
if (png_get_sRGB(png_ptr, info_ptr, &intent)
if (png_get_sRGB(png_ptr, info_ptr, &intent))
png_set_sRGB(png_ptr, intent, 0);
else
if (png_get_gAMA(png_ptr, info_ptr, &image_gamma)
if (png_get_gAMA(png_ptr, info_ptr, &image_gamma))
png_set_gamma(png_ptr, screen_gamma, image_gamma);
else
png_set_gamma(png_ptr, screen_gamma, 0.50);
@@ -234,7 +234,7 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
png_colorp palette;
/* This reduces the image to the application supplied palette */
if (we have our own palette)
if (/* we have our own palette */)
{
/* An array of colors to which the image should be dithered */
png_color std_color_cube[MAX_SCREEN_COLORS];
@@ -243,7 +243,7 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
MAX_SCREEN_COLORS, 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)))
else if (png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette))
{
png_color16p histogram;
@@ -304,37 +304,37 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
}
/* Now it's time to read the image. One of these methods is REQUIRED */
**** Read the entire image in one go ****
#ifdef entire /* Read the entire image in one go */
png_read_image(png_ptr, row_pointers);
**** Read the image one or more scanlines at a time ****
#else no_entire /* Read the image one or more scanlines at a time */
/* The other way to read images - deal with interlacing: */
for (pass = 0; pass < number_passes; pass++)
{
[[[[[[[ Read the image a single row at a time ]]]]]]]
#ifdef single /* Read the image a single row at a time */
for (y = 0; y < height; y++)
{
png_bytep row_pointers = row[y];
png_read_rows(png_ptr, &row_pointers, NULL, 1);
}
[[[[[[[ Read the image several rows at a time ]]]]]]]
#else no_single /* Read the image several rows at a time */
for (y = 0; y < height; y += number_of_rows)
{
<<<<<<<<<< Read the image using the "sparkle" effect. >>>>>>>>>>
#ifdef sparkle /* Read the image using the "sparkle" effect. */
png_read_rows(png_ptr, row_pointers, NULL, number_of_rows);
<<<<<<<<<< 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, number_of_rows);
<<<<<<<<<< use only one of these two methods >>>>>>>>>>
#endif no_sparkle /* use only one of these two methods */
}
/* if you want to display the image after every pass, do
so here */
[[[[[[[ use only one of these two methods ]]]]]]]
#endif no_single /* use only one of these two methods */
}
**** use only one of these two methods ****
#endif no_entire /* use only one of these two methods */
/* read rest of file, and get additional chunks in info_ptr - REQUIRED */
png_read_end(png_ptr, info_ptr);
@@ -479,7 +479,7 @@ end_callback(png_structp png_ptr, png_infop info)
}
/* write a png file */
void write_png(char *file_name, ... other image information ...)
void write_png(char *file_name /* , ... other image information ... */)
{
FILE *fp;
png_structp png_ptr;
@@ -526,16 +526,16 @@ void write_png(char *file_name, ... other image information ...)
}
/* One of the following I/O initialization functions is REQUIRED */
**** I/O initialization method 1 ****
#ifdef streams /* I/O initialization method 1 */
/* set up the output control if you are using standard C streams */
png_init_io(png_ptr, fp);
**** I/O initialization method 2 ****
#else no_streams /* I/O initialization method 2 */
/* If you are using replacement read functions, instead of calling
* png_init_io() here you would call */
png_set_write_fn(png_ptr, (void *)user_io_ptr, user_write_fn,
user_IO_flush_function);
/* where user_io_ptr is a structure you want available to the callbacks */
**** only use 1 initialization method ****
#endif no_streams /* only use one initialization method */
/* 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
@@ -550,7 +550,7 @@ void write_png(char *file_name, ... other image information ...)
/* set the palette if there is one. REQUIRED for indexed-color images */
palette = (png_colorp)png_malloc(png_ptr, 256 * sizeof (png_color));
... set palette colors ...
/* ... set palette colors ... */
png_set_PLTE(png_ptr, info_ptr, palette, 256);
/* optional significant bit chunk */
@@ -640,12 +640,12 @@ void write_png(char *file_name, ... other image information ...)
png_byte row_pointers[height][width];
/* One of the following output methods is REQUIRED */
**** write out the entire image data in one call ***
#ifdef entire /* write out the entire image data in one call */
png_write_image(png_ptr, row_pointers);
/* the other way to write the image - deal with interlacing */
**** write out the image data by one or more scanlines ****
#else no_entire /* write out the image data by one or more scanlines */
/* The number of passes is either 1 for non-interlaced images,
* or 7 for interlaced images.
*/
@@ -661,7 +661,7 @@ void write_png(char *file_name, ... other image information ...)
png_write_rows(png_ptr, &row_pointers, 1);
}
}
**** use only one output method ****
#endif no_entire /* use only one output method */
/* You can write optional chunks like tEXt, zTXt, and tIME at the end
* as well.