forked from AuroraMiddleware/gtk
146 lines
3.6 KiB
C
146 lines
3.6 KiB
C
/* GdkPixbuf library - JPEG image loader
|
||
*
|
||
* Copyright (C) 1999 Michael Zucchi
|
||
* Copyright (C) 1999 The Free Software Foundation
|
||
*
|
||
* Authors: Michael Zucchi <zucchi@zedzone.mmc.com.au>
|
||
* Federico Mena-Quintero <federico@gimp.org>
|
||
*
|
||
* This library is free software; you can redistribute it and/or
|
||
* modify it under the terms of the GNU Library General Public
|
||
* License as published by the Free Software Foundation; either
|
||
* version 2 of the License, or (at your option) any later version.
|
||
*
|
||
* This library 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
|
||
* Library General Public License for more details.
|
||
*
|
||
* You should have received a copy of the GNU Library General Public
|
||
* License along with this library; if not, write to the
|
||
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
||
* Boston, MA 02111-1307, USA.
|
||
*/
|
||
|
||
#include <config.h>
|
||
#include <stdio.h>
|
||
#include <setjmp.h>
|
||
#include <jpeglib.h>
|
||
#include "gdk-pixbuf.h"
|
||
|
||
|
||
|
||
/* error handler data */
|
||
struct error_handler_data {
|
||
struct jpeg_error_mgr pub;
|
||
sigjmp_buf setjmp_buffer;
|
||
};
|
||
|
||
static void
|
||
fatal_error_handler (j_common_ptr cinfo)
|
||
{
|
||
/* FIXME:
|
||
* We should somehow signal what error occurred to the caller so the
|
||
* caller can handle the error message */
|
||
struct error_handler_data *errmgr;
|
||
|
||
errmgr = (struct error_handler_data *) cinfo->err;
|
||
cinfo->err->output_message (cinfo);
|
||
siglongjmp (errmgr->setjmp_buffer, 1);
|
||
return;
|
||
}
|
||
|
||
/* Destroy notification function for the libart pixbuf */
|
||
static void
|
||
free_buffer (gpointer user_data, gpointer data)
|
||
{
|
||
free (data);
|
||
}
|
||
|
||
/* Shared library entry point */
|
||
GdkPixbuf *
|
||
image_load (FILE *f)
|
||
{
|
||
int w, h, i, j;
|
||
guchar *pixels = NULL;
|
||
guchar *dptr;
|
||
guchar *lines[4]; /* Used to expand rows, via rec_outbuf_height, from the header file:
|
||
* "* Usually rec_outbuf_height will be 1 or 2, at most 4."
|
||
*/
|
||
guchar **lptr;
|
||
struct jpeg_decompress_struct cinfo;
|
||
struct error_handler_data jerr;
|
||
GdkPixbuf *pixbuf;
|
||
|
||
/* setup error handler */
|
||
cinfo.err = jpeg_std_error (&jerr.pub);
|
||
jerr.pub.error_exit = fatal_error_handler;
|
||
|
||
if (sigsetjmp (jerr.setjmp_buffer, 1)) {
|
||
/* Whoops there was a jpeg error */
|
||
if (pixels)
|
||
free (pixels);
|
||
|
||
jpeg_destroy_decompress (&cinfo);
|
||
return NULL;
|
||
}
|
||
|
||
/* load header, setup */
|
||
jpeg_create_decompress (&cinfo);
|
||
jpeg_stdio_src (&cinfo, f);
|
||
jpeg_read_header (&cinfo, TRUE);
|
||
jpeg_start_decompress (&cinfo);
|
||
cinfo.do_fancy_upsampling = FALSE;
|
||
cinfo.do_block_smoothing = FALSE;
|
||
|
||
w = cinfo.output_width;
|
||
h = cinfo.output_height;
|
||
|
||
pixels = malloc (h * w * 3);
|
||
if (!pixels) {
|
||
jpeg_destroy_decompress (&cinfo);
|
||
return NULL;
|
||
}
|
||
|
||
dptr = pixels;
|
||
|
||
/* decompress all the lines, a few at a time */
|
||
|
||
while (cinfo.output_scanline < cinfo.output_height) {
|
||
lptr = lines;
|
||
for (i = 0; i < cinfo.rec_outbuf_height; i++) {
|
||
*lptr++ = dptr;
|
||
dptr += w * 3;
|
||
}
|
||
|
||
jpeg_read_scanlines (&cinfo, lines, cinfo.rec_outbuf_height);
|
||
if (cinfo.output_components == 1) {
|
||
/* Expand grey->colour. Expand from the end of the
|
||
* memory down, so we can use the same buffer.
|
||
*/
|
||
for (i = cinfo.rec_outbuf_height - 1; i >= 0; i--) {
|
||
guchar *from, *to;
|
||
|
||
from = lines[i] + w - 1;
|
||
to = lines[i] + w * 3 - 3;
|
||
for (j = w - 1; j >= 0; j--) {
|
||
to[0] = from[0];
|
||
to[1] = from[0];
|
||
to[2] = from[0];
|
||
to -= 3;
|
||
from--;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
jpeg_finish_decompress (&cinfo);
|
||
jpeg_destroy_decompress (&cinfo);
|
||
|
||
return gdk_pixbuf_new_from_data (pixels, ART_PIX_RGB, FALSE,
|
||
w, h, w * 3,
|
||
free_buffer, NULL);
|
||
|
||
return pixbuf;
|
||
}
|