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146 lines
3.6 KiB
C
146 lines
3.6 KiB
C
/* GdkPixbuf library - JPEG image loader
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*
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* Copyright (C) 1999 Michael Zucchi
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* Copyright (C) 1999 The Free Software Foundation
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*
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* Authors: Michael Zucchi <zucchi@zedzone.mmc.com.au>
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* Federico Mena-Quintero <federico@gimp.org>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library 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 GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <setjmp.h>
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#include <jpeglib.h>
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#include "gdk-pixbuf.h"
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/* error handler data */
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struct error_handler_data {
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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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fatal_error_handler (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 error_handler_data *errmgr;
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errmgr = (struct error_handler_data *) 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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/* Destroy notification function for the libart pixbuf */
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static void
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free_buffer (gpointer user_data, gpointer data)
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{
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free (data);
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}
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/* Shared library entry point */
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GdkPixbuf *
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image_load (FILE *f)
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{
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int w, h, i, j;
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guchar *pixels = NULL;
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guchar *dptr;
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guchar *lines[4]; /* Used to expand rows, via rec_outbuf_height, from the header file:
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* "* Usually rec_outbuf_height will be 1 or 2, at most 4."
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*/
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guchar **lptr;
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struct jpeg_decompress_struct cinfo;
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struct error_handler_data 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 = fatal_error_handler;
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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)
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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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jpeg_start_decompress (&cinfo);
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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 = malloc (h * w * 3);
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if (!pixels) {
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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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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. Expand from the end of the
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* memory down, so we can use the same buffer.
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*/
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for (i = cinfo.rec_outbuf_height - 1; i >= 0; i--) {
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guchar *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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return gdk_pixbuf_new_from_data (pixels, ART_PIX_RGB, FALSE,
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w, h, w * 3,
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free_buffer, NULL);
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return pixbuf;
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}
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