mirror of https://github.com/koreader/koreader
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: Makefilepull/2/merge
Tigran Aivazian
12 years ago
committed by
Qingping Hou
parent
8c6fd35789
commit
6c9a3c3dc5
@ -0,0 +1,84 @@
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/*
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KindlePDFViewer: JPEG support for Picture Viewer module
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Copyright (C) 2012 Tigran Aivazian <tigran@bibles.org.uk>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdint.h>
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#include <string.h>
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#include <setjmp.h>
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#include <stdio.h>
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#include "jpeglib.h"
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struct my_error_mgr {
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struct jpeg_error_mgr pub;
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jmp_buf setjmp_buffer;
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};
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typedef struct my_error_mgr *my_error_ptr;
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METHODDEF(void) my_error_exit(j_common_ptr cinfo)
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{
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my_error_ptr myerr = (my_error_ptr) cinfo->err;
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(*cinfo->err->output_message) (cinfo);
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longjmp(myerr->setjmp_buffer, 1);
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}
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uint8_t *jpegLoadFile(const char *fname, int *width, int *height, int *components)
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{
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struct jpeg_decompress_struct cinfo;
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struct my_error_mgr jerr;
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FILE *infile;
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JSAMPARRAY buffer;
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int row_stride;
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long cont;
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JSAMPLE *image_buffer;
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if ((infile = fopen(fname, "r")) == NULL) return NULL;
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cinfo.err = jpeg_std_error(&jerr.pub);
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jerr.pub.error_exit = my_error_exit;
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if (setjmp(jerr.setjmp_buffer)) {
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jpeg_destroy_decompress(&cinfo);
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fclose(infile);
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return NULL;
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}
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jpeg_create_decompress(&cinfo);
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jpeg_stdio_src(&cinfo, infile);
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(void) jpeg_read_header(&cinfo, TRUE);
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(void) jpeg_start_decompress(&cinfo);
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row_stride = cinfo.output_width * cinfo.output_components;
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buffer = (*cinfo.mem->alloc_sarray)
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((j_common_ptr) & cinfo, JPOOL_IMAGE, row_stride, 1);
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image_buffer = (JSAMPLE *) malloc(cinfo.image_width*cinfo.image_height*cinfo.output_components);
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if (image_buffer == NULL) return NULL;
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*width = cinfo.image_width;
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*height = cinfo.image_height;
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//cont = cinfo.output_height - 1;
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cont = 0;
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while (cinfo.output_scanline < cinfo.output_height) {
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(void) jpeg_read_scanlines(&cinfo, buffer, 1);
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memcpy(image_buffer + cinfo.image_width * cinfo.output_components * cont, buffer[0], row_stride);
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cont++;
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}
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(void) jpeg_finish_decompress(&cinfo);
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jpeg_destroy_decompress(&cinfo);
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fclose(infile);
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*components = cinfo.output_components;
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return (uint8_t *)image_buffer;
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}
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@ -0,0 +1,30 @@
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/*
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KindlePDFViewer: Interface to JPEG module for picture viewer
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Copyright (C) 2012 Tigran Aivazian <tigran@bibles.org.uk>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _PIC_JPEG_H
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#define _PIC_JPEG_H
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/* each new image format must provide fmtLoadFile() function which
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* performs the following:
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* 1. Opens the file 'filename'
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* 2. Reads the image data from it into a buffer allocated with malloc()
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* 3. Fills in the image *width, *height and *components (number of bytes per pixel)
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* 4. Closes the file
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* 5. Returns the pointer to the image data
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*/
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extern uint8_t *jpegLoadFile(const char *fname, int *width, int *height, int *components);
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#endif
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