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130 lines
2.9 KiB
C
130 lines
2.9 KiB
C
/*
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io-jpeg.c: GdkPixBuf loader for jpeg files.
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Based on io-jpeg from gdk_imlib, but not much.
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This code is licensed under the Lesser GNU
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General Public License, version 2.1.
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Author:
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Michael Zucchi <zucchi@zedzone.mmc.com.au>
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*/
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#include <config.h>
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#include <stdio.h>
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#include <glib.h>
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#include <setjmp.h>
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#include "gdk-pixbuf.h"
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/*#include "gdk-pixbuf-io.h"*/
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#include <jpeglib.h>
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/* error handler data */
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struct iojpeg_JPEG_error_mgr
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{
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struct jpeg_error_mgr pub;
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sigjmp_buf setjmp_buffer;
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};
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static void
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g_JPEGFatalErrorHandler(j_common_ptr cinfo)
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{
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/* FIXME:
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* We should somehow signal what error occurred to the caller so the
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* caller can handle the error message */
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struct iojpeg_JPEG_error_mgr *errmgr;
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errmgr = (struct iojpeg_JPEG_error_mgr *) cinfo->err;
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cinfo->err->output_message(cinfo);
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siglongjmp(errmgr->setjmp_buffer, 1);
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return;
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}
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GdkPixBuf *image_load(FILE *f)
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{
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int w,h,i,j;
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art_u8 *pixels=NULL, *dptr, *fptr, *pptr;
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unsigned char *lines[4], /* Used to expand rows, via rec_outbuf_height, from
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the header file:
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"* Usually rec_outbuf_height will be 1 or 2, at most 4." */
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**lptr;
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struct jpeg_decompress_struct cinfo;
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struct iojpeg_JPEG_error_mgr jerr;
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GdkPixBuf *pixbuf;
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/* setup error handler */
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cinfo.err = jpeg_std_error(&(jerr.pub));
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jerr.pub.error_exit = g_JPEGFatalErrorHandler;
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if (sigsetjmp(jerr.setjmp_buffer, 1)) {
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/* Whoops there was a jpeg error */
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if (pixels != NULL)
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art_free(pixels);
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jpeg_destroy_decompress(&cinfo);
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return NULL;
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}
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/* load header, setup */
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jpeg_create_decompress(&cinfo);
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jpeg_stdio_src(&cinfo, f);
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jpeg_read_header(&cinfo, TRUE);
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cinfo.do_fancy_upsampling = FALSE;
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cinfo.do_block_smoothing = FALSE;
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w = cinfo.output_width;
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h = cinfo.output_height;
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pixels = art_alloc(h * w * 3);
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if (pixels == NULL) {
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jpeg_destroy_decompress(&cinfo);
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return NULL;
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}
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dptr = pixels;
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/* decompress all the lines, a few at a time */
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jpeg_start_decompress(&cinfo);
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while (cinfo.output_scanline < cinfo.output_height) {
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lptr = lines;
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for (i=0;i<cinfo.rec_outbuf_height;i++) {
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*lptr++=dptr;
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dptr+=w*3;
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}
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jpeg_read_scanlines(&cinfo, lines, cinfo.rec_outbuf_height);
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if (cinfo.output_components==1) {
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/* expand grey->colour */
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/* expand from the end of the memory down, so we can use
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the same buffer */
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for (i=cinfo.rec_outbuf_height-1;i>=0;i--) {
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unsigned char *from, *to;
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from = lines[i]+w-1;
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to = lines[i]+w*3-3;
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for (j=w-1;j>=0;j++) {
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to[0] = from[0];
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to[1] = from[0];
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to[2] = from[0];
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to-=3;
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from--;
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}
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}
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}
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}
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jpeg_finish_decompress(&cinfo);
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jpeg_destroy_decompress(&cinfo);
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/* finish off, create the pixbuf */
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pixbuf = g_new(GdkPixBuf, 1);
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pixbuf->art_pixbuf = art_pixbuf_new_rgb(pixels, w, h, (w * 3));
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if (!(pixbuf->art_pixbuf))
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return NULL;
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pixbuf->ref_count = 0;
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pixbuf->unref_func = NULL;
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return pixbuf;
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}
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/*
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* Local variables:
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* c-basic-offset: 8
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* End:
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*/
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