kolibrios/programs/network/netsurf/libnsgif/examples/decode_gif.c

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/*
* Copyright 2008 Sean Fox <dyntryx@gmail.com>
* Copyright 2008 James Bursa <james@netsurf-browser.org>
*
* This file is part of NetSurf's libnsgif, http://www.netsurf-browser.org/
* Licenced under the MIT License,
* http://www.opensource.org/licenses/mit-license.php
*/
#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include "../libnsgif.h"
unsigned char *load_file(const char *path, size_t *data_size);
void warning(const char *context, int code);
void *bitmap_create(int width, int height);
void bitmap_set_opaque(void *bitmap, bool opaque);
bool bitmap_test_opaque(void *bitmap);
unsigned char *bitmap_get_buffer(void *bitmap);
void bitmap_destroy(void *bitmap);
void bitmap_modified(void *bitmap);
int main(int argc, char *argv[])
{
gif_bitmap_callback_vt bitmap_callbacks = {
bitmap_create,
bitmap_destroy,
bitmap_get_buffer,
bitmap_set_opaque,
bitmap_test_opaque,
bitmap_modified
};
gif_animation gif;
size_t size;
gif_result code;
unsigned int i;
if (argc != 2) {
fprintf(stderr, "Usage: %s image.gif\n", argv[0]);
return 1;
}
/* create our gif animation */
gif_create(&gif, &bitmap_callbacks);
/* load file into memory */
unsigned char *data = load_file(argv[1], &size);
/* begin decoding */
do {
code = gif_initialise(&gif, size, data);
if (code != GIF_OK && code != GIF_WORKING) {
warning("gif_initialise", code);
exit(1);
}
} while (code != GIF_OK);
printf("P3\n");
printf("# %s\n", argv[1]);
printf("# width %u \n", gif.width);
printf("# height %u \n", gif.height);
printf("# frame_count %u \n", gif.frame_count);
printf("# frame_count_partial %u \n", gif.frame_count_partial);
printf("# loop_count %u \n", gif.loop_count);
printf("%u %u 256\n", gif.width, gif.height * gif.frame_count);
/* decode the frames */
for (i = 0; i != gif.frame_count; i++) {
unsigned int row, col;
unsigned char *image;
code = gif_decode_frame(&gif, i);
if (code != GIF_OK)
warning("gif_decode_frame", code);
printf("# frame %u:\n", i);
image = (unsigned char *) gif.frame_image;
for (row = 0; row != gif.height; row++) {
for (col = 0; col != gif.width; col++) {
size_t z = (row * gif.width + col) * 4;
printf("%u %u %u ",
(unsigned char) image[z],
(unsigned char) image[z + 1],
(unsigned char) image[z + 2]);
}
printf("\n");
}
}
/* clean up */
gif_finalise(&gif);
free(data);
return 0;
}
unsigned char *load_file(const char *path, size_t *data_size)
{
FILE *fd;
struct stat sb;
unsigned char *buffer;
size_t size;
size_t n;
fd = fopen(path, "rb");
if (!fd) {
perror(path);
exit(EXIT_FAILURE);
}
if (stat(path, &sb)) {
perror(path);
exit(EXIT_FAILURE);
}
size = sb.st_size;
buffer = malloc(size);
if (!buffer) {
fprintf(stderr, "Unable to allocate %lld bytes\n",
(long long) size);
exit(EXIT_FAILURE);
}
n = fread(buffer, 1, size, fd);
if (n != size) {
perror(path);
exit(EXIT_FAILURE);
}
fclose(fd);
*data_size = size;
return buffer;
}
void warning(const char *context, gif_result code)
{
fprintf(stderr, "%s failed: ", context);
switch (code)
{
case GIF_INSUFFICIENT_FRAME_DATA:
fprintf(stderr, "GIF_INSUFFICIENT_FRAME_DATA");
break;
case GIF_FRAME_DATA_ERROR:
fprintf(stderr, "GIF_FRAME_DATA_ERROR");
break;
case GIF_INSUFFICIENT_DATA:
fprintf(stderr, "GIF_INSUFFICIENT_DATA");
break;
case GIF_DATA_ERROR:
fprintf(stderr, "GIF_DATA_ERROR");
break;
case GIF_INSUFFICIENT_MEMORY:
fprintf(stderr, "GIF_INSUFFICIENT_MEMORY");
break;
default:
fprintf(stderr, "unknown code %i", code);
break;
}
fprintf(stderr, "\n");
}
void *bitmap_create(int width, int height)
{
return calloc(width * height, 4);
}
void bitmap_set_opaque(void *bitmap, bool opaque)
{
(void) opaque; /* unused */
assert(bitmap);
}
bool bitmap_test_opaque(void *bitmap)
{
assert(bitmap);
return false;
}
unsigned char *bitmap_get_buffer(void *bitmap)
{
assert(bitmap);
return bitmap;
}
void bitmap_destroy(void *bitmap)
{
assert(bitmap);
free(bitmap);
}
void bitmap_modified(void *bitmap)
{
assert(bitmap);
return;
}