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koreader/pic_jpeg.c
Tigran Aivazian 6c9a3c3dc5 Factor out JPEG support into a module
This is to make adding support for new formats easier.
See the file pic_jpeg.h for the description of the interface that each
image format must support.

Conflicts:

	Makefile
2012-10-31 20:54:24 -04:00

85 lines
2.5 KiB
C

/*
KindlePDFViewer: JPEG support for Picture Viewer module
Copyright (C) 2012 Tigran Aivazian <tigran@bibles.org.uk>
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 3 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, see <http://www.gnu.org/licenses/>.
*/
#include <stdint.h>
#include <string.h>
#include <setjmp.h>
#include <stdio.h>
#include "jpeglib.h"
struct my_error_mgr {
struct jpeg_error_mgr pub;
jmp_buf setjmp_buffer;
};
typedef struct my_error_mgr *my_error_ptr;
METHODDEF(void) my_error_exit(j_common_ptr cinfo)
{
my_error_ptr myerr = (my_error_ptr) cinfo->err;
(*cinfo->err->output_message) (cinfo);
longjmp(myerr->setjmp_buffer, 1);
}
uint8_t *jpegLoadFile(const char *fname, int *width, int *height, int *components)
{
struct jpeg_decompress_struct cinfo;
struct my_error_mgr jerr;
FILE *infile;
JSAMPARRAY buffer;
int row_stride;
long cont;
JSAMPLE *image_buffer;
if ((infile = fopen(fname, "r")) == NULL) return NULL;
cinfo.err = jpeg_std_error(&jerr.pub);
jerr.pub.error_exit = my_error_exit;
if (setjmp(jerr.setjmp_buffer)) {
jpeg_destroy_decompress(&cinfo);
fclose(infile);
return NULL;
}
jpeg_create_decompress(&cinfo);
jpeg_stdio_src(&cinfo, infile);
(void) jpeg_read_header(&cinfo, TRUE);
(void) jpeg_start_decompress(&cinfo);
row_stride = cinfo.output_width * cinfo.output_components;
buffer = (*cinfo.mem->alloc_sarray)
((j_common_ptr) & cinfo, JPOOL_IMAGE, row_stride, 1);
image_buffer = (JSAMPLE *) malloc(cinfo.image_width*cinfo.image_height*cinfo.output_components);
if (image_buffer == NULL) return NULL;
*width = cinfo.image_width;
*height = cinfo.image_height;
//cont = cinfo.output_height - 1;
cont = 0;
while (cinfo.output_scanline < cinfo.output_height) {
(void) jpeg_read_scanlines(&cinfo, buffer, 1);
memcpy(image_buffer + cinfo.image_width * cinfo.output_components * cont, buffer[0], row_stride);
cont++;
}
(void) jpeg_finish_decompress(&cinfo);
jpeg_destroy_decompress(&cinfo);
fclose(infile);
*components = cinfo.output_components;
return (uint8_t *)image_buffer;
}