gtk/gdk-pixbuf/io-gif.c

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/*
* io-gif.c: GdkPixBuf I/O for GIF files.
* ...second verse, same as the first...
*
* Copyright (C) 1999 Mark Crichton
* Author: Mark Crichton <crichton@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, Cambridge, MA 02139, USA.
*
*/
#include <config.h>
#include <stdio.h>
#include <glib.h>
#include "gdk-pixbuf.h"
#include "gdk-pixbuf-io.h"
#include <gif_lib.h>
/* Shared library entry point */
GdkPixBuf *image_load(FILE * f)
{
gint fn, is_trans = FALSE;
gint done = 0;
gint t_color = -1;
gint w, h, i, j;
art_u8 *pixels, *tmpptr;
GifFileType *gif;
GifRowType *rows;
GifRecordType rec;
ColorMapObject *cmap;
int intoffset[] =
{0, 4, 2, 1};
int intjump[] =
{8, 8, 4, 2};
GdkPixBuf *pixbuf;
ArtPixBuf *art_pixbuf;
g_return_val_if_fail(f != NULL, NULL);
fn = fileno(f);
/* lseek(fn, 0, 0);*/
gif = DGifOpenFileHandle(fn);
if (!gif) {
g_error("DGifOpenFilehandle FAILED");
PrintGifError();
return NULL;
}
/* Now we do the ungodly mess of loading a GIF image
* I used to remember when I liked this file format...
* of course, I still coded in assembler then.
* This comes from gdk_imlib, with some cleanups.
*/
do {
if (DGifGetRecordType(gif, &rec) == GIF_ERROR) {
PrintGifError();
rec = TERMINATE_RECORD_TYPE;
}
if ((rec == IMAGE_DESC_RECORD_TYPE) && (!done)) {
if (DGifGetImageDesc(gif) == GIF_ERROR) {
PrintGifError();
rec = TERMINATE_RECORD_TYPE;
}
w = gif->Image.Width;
h = gif->Image.Height;
rows = g_malloc0(h * sizeof(GifRowType *));
if (!rows) {
DGifCloseFile(gif);
return NULL;
}
for (i = 0; i < h; i++) {
rows[i] = g_malloc0(w * sizeof(GifPixelType));
if (!rows[i]) {
DGifCloseFile(gif);
for (i = 0; i < h; i++)
if (rows[i])
g_free(rows[i]);
free(rows);
return NULL;
}
}
if (gif->Image.Interlace) {
for (i = 0; i < 4; i++) {
for (j = intoffset[i]; j < h; j += intjump[i])
DGifGetLine(gif, rows[j], w);
}
} else {
for (i = 0; i < h; i++)
DGifGetLine(gif, rows[i], w);
}
done = 1;
} else if (rec == EXTENSION_RECORD_TYPE) {
gint ext_code;
GifByteType *ext;
DGifGetExtension(gif, &ext_code, &ext);
while (ext) {
if ((ext_code == 0xf9) &&
(ext[1] & 1) && (t_color < 0)) {
is_trans = TRUE;
t_color = (gint) ext[4];
}
ext = NULL;
DGifGetExtensionNext(gif, &ext);
}
}
}
while (rec != TERMINATE_RECORD_TYPE);
/* Ok, we're loaded, now to convert from indexed -> RGB
* with alpha if necessary
*/
if (is_trans)
pixels = art_alloc(h * w * 4);
else
pixels = art_alloc(h * w * 3);
tmpptr = pixels;
if (!pixels)
return NULL;
/* The meat of the transformation */
/* Get the right palette */
cmap = (gif->Image.ColorMap ? gif->Image.ColorMap : gif->SColorMap);
/* Unindex the data, and pack it in RGB(A) order.
* Note for transparent GIFs, the alpha is set to 0
* for the transparent color, and 0xFF for everything else.
* I think that's right...
*/
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
tmpptr[0] = cmap->Colors[rows[i][j]].Red;
tmpptr[1] = cmap->Colors[rows[i][j]].Green;
tmpptr[2] = cmap->Colors[rows[i][j]].Blue;
if (is_trans && (rows[i][j] == t_color))
tmpptr[3] = 0;
else
tmpptr[3] = 0xFF;
tmpptr += (is_trans ? 4 : 3);
}
g_free(rows[i]);
}
g_free(rows);
if (is_trans)
art_pixbuf = art_pixbuf_new_rgba(pixels, w, h, (w * 4));
else
art_pixbuf = art_pixbuf_new_rgb(pixels, w, h, (w * 3));
pixbuf = gdk_pixbuf_new (art_pixbuf, NULL);
/* Ok, I'm anal...shoot me */
if (!pixbuf)
art_free(pixels);
return pixbuf;
}
image_save() {}