forked from rbu/driftnet
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png.c
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png.c
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/*
* png.c:
* PNG image support.
*
* Copyright (c) 2003 Drew Roedersheimer, Chris Lightfoot. All rights reserved.
* Email: chris@ex-parrot.com; WWW: http://www.ex-parrot.com/~chris/
*
*/
#ifndef NO_DISPLAY_WINDOW
#include <png.h>
#include "img.h"
static const char rcsid[] = "$Id: png.c,v 1.4 2003/08/25 12:23:43 chris Exp $";
int png_load_hdr(img I) {
unsigned char sig[PNG_SIG_LEN];
png_structp png_ptr;
png_infop info_ptr;
rewind(I->fp);
if (fread(sig, sizeof(sig[0]), PNG_SIG_LEN, I->fp) != PNG_SIG_LEN) {
return(0);
}
/* Check the PNG signature of the file */
if (png_sig_cmp(sig, (png_size_t)0, PNG_SIG_LEN)) {
I->err = IE_HDRFORMAT;
return 0;
}
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
NULL, NULL, NULL);
if (png_ptr == NULL) {
I->err = IE_HDRFORMAT;
return 0;
}
info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL) {
png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
I->err = IE_HDRFORMAT;
return 0;
}
rewind(I->fp);
png_init_io(png_ptr, I->fp);
png_read_info(png_ptr, info_ptr);
I->width = png_get_image_width(png_ptr, info_ptr);
I->height = png_get_image_height(png_ptr, info_ptr);
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
return(1);
}
int png_abort_load(img I) {
return 1;
}
int png_load_img(img I) {
unsigned char **p, **q;
png_structp png_ptr;
png_infop info_ptr;
png_uint_32 width, height;
int i, j, bit_depth, color_type, interlace_type;
png_bytepp row_pointers;
img_alloc(I);
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
NULL, NULL, NULL);
if (png_ptr == NULL) {
I->err = IE_HDRFORMAT;
return 0;
}
info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL) {
png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
I->err = IE_HDRFORMAT;
return 0;
}
rewind(I->fp);
png_init_io(png_ptr, I->fp);
png_read_info(png_ptr, info_ptr);
/* Get image specific data */
png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
&interlace_type, NULL, NULL);
/* Convert greyscale images to 8-bit RGB */
if (color_type == PNG_COLOR_TYPE_GRAY ||
color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
if (bit_depth < 8) {
png_set_expand_gray_1_2_4_to_8(png_ptr);
}
png_set_gray_to_rgb(png_ptr);
}
/* Change paletted images to RGB */
if (color_type == PNG_COLOR_TYPE_PALETTE)
png_set_expand(png_ptr);
if (bit_depth < 8)
png_set_expand(png_ptr);
if (bit_depth == 16)
png_set_strip_16(png_ptr);
/* The gdk img widget appears to expect 8-bit RGB followed by a
* filler byte. */
png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
/* Update the info structure after the transforms */
png_read_update_info(png_ptr, info_ptr);
/* png_set_rows(png_ptr, info_ptr, row_pointers)*/
/* Allocate space before reading the image */
row_pointers = png_malloc(png_ptr, height * sizeof(png_bytep));
for (i = 0; i < height; i++) {
row_pointers[i] = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
}
/* Read in the image and copy it to the gdk img structure */
png_read_image(png_ptr, row_pointers);
p = (unsigned char **)I->data;
q = (unsigned char **)row_pointers;
for (i = 0; i < height; i++) {
for (j = 0; j < png_get_rowbytes(png_ptr, info_ptr); j++) {
p[i][j] = q[i][j];
}
}
png_read_end(png_ptr, info_ptr);
/* Clean up */
png_free(png_ptr, row_pointers);
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
return 1;
}
int png_save_img(const img I, FILE *fp) {
return 1;
}
#endif /* !NO_DISPLAY_WINDOW */