Schlimm is an attempt to create a fork of the SLiM desktop manager.
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/****************************************************************************
png.c - read and write png images using libpng routines.
Distributed with Xplanet.
Copyright (C) 2002 Hari Nair <hari@alumni.caltech.edu>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
****************************************************************************/
#include "png.h"
int
read_png(const char *filename, int *width, int *height, unsigned char **rgb,
unsigned char **alpha)
{
int ret = 0;
png_structp png_ptr;
png_infop info_ptr;
png_bytepp row_pointers;
unsigned char *ptr = NULL;
png_uint_32 w, h;
int bit_depth, color_type, interlace_type;
int i;
FILE *infile = fopen(filename, "rb");
if (infile == NULL) {
fprintf(stderr, "Can not fopen file: %s\n", filename);
return ret;
}
png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
(png_voidp)NULL,
(png_error_ptr)NULL,
(png_error_ptr)NULL);
if (!png_ptr)
goto file_close;
info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr) {
png_destroy_read_struct(&png_ptr,
(png_infopp)NULL,
(png_infopp)NULL);
}
#if PNG_LIBPNG_VER_MAJOR >= 1 && PNG_LIBPNG_VER_MINOR >= 4
if (setjmp(png_jmpbuf((png_ptr))))
#else
if (setjmp(png_ptr->jmpbuf))
#endif
goto png_destroy;
png_init_io(png_ptr, infile);
png_read_info(png_ptr, info_ptr);
png_get_IHDR(png_ptr, info_ptr, &w, &h, &bit_depth, &color_type,
&interlace_type, (int *) NULL, (int *) NULL);
/* Prevent against integer overflow */
if (w >= MAX_DIMENSION || h >= MAX_DIMENSION) {
fprintf(stderr,
"Unreasonable dimension found in file: %s\n", filename);
goto png_destroy;
}
*width = (int) w;
*height = (int) h;
if (color_type == PNG_COLOR_TYPE_RGB_ALPHA
|| color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
alpha[0] = malloc(*width * *height);
if (alpha[0] == NULL) {
fprintf(stderr,
"Can't allocate memory for alpha channel in PNG file.\n");
goto png_destroy;
}
}
/* Change a paletted/grayscale image to RGB */
if (color_type == PNG_COLOR_TYPE_PALETTE && bit_depth <= 8)
png_set_expand(png_ptr);
/* Change a grayscale image to RGB */
if (color_type == PNG_COLOR_TYPE_GRAY ||
color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
png_set_gray_to_rgb(png_ptr);
/* If the PNG file has 16 bits per channel, strip them down to 8 */
if (bit_depth == 16)
png_set_strip_16(png_ptr);
/* use 1 byte per pixel */
png_set_packing(png_ptr);
row_pointers = malloc(*height * sizeof(png_bytep));
if (row_pointers == NULL) {
fprintf(stderr, "Can't allocate memory for PNG file.\n");
goto png_destroy;
}
for (i = 0; i < *height; i++) {
row_pointers[i] = malloc(4 * *width);
if (row_pointers == NULL) {
fprintf(stderr,
"Can't allocate memory for PNG line.\n");
goto rows_free;
}
}
png_read_image(png_ptr, row_pointers);
rgb[0] = malloc(3 * *width * *height);
if (rgb[0] == NULL) {
fprintf(stderr, "Can't allocate memory for PNG file.\n");
goto rows_free;
}
if (alpha[0] == NULL) {
ptr = rgb[0];
for (i = 0; i < *height; i++) {
memcpy(ptr, row_pointers[i], 3 * *width);
ptr += 3 * *width;
}
} else {
int j;
ptr = rgb[0];
for (i = 0; i < *height; i++) {
int ipos = 0;
for (j = 0; j < *width; j++) {
*ptr++ = row_pointers[i][ipos++];
*ptr++ = row_pointers[i][ipos++];
*ptr++ = row_pointers[i][ipos++];
alpha[0][i * *width + j]
= row_pointers[i][ipos++];
}
}
}
ret = 1; /* data reading is OK */
rows_free:
for (i = 0; i < *height; i++) {
if (row_pointers[i] != NULL)
free(row_pointers[i]);
}
free(row_pointers);
png_destroy:
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp) NULL);
file_close:
fclose(infile);
return ret;
}