]> Pileus Git - ~andy/gtk/blobdiff - gdk-pixbuf/io-gif.c
Add icc-profile option to gdk-pixbuf for the TIFF image format
[~andy/gtk] / gdk-pixbuf / io-gif.c
index 2fb964b66a798577c84c8f3ea7039b5dfe13cfe3..d414d782013def3a6dd29ed42c26ef88fd8af66d 100644 (file)
-/*
- * io-gif.c: GdkPixBuf I/O for GIF files.
- * ...second verse, same as the first...
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*- */
+/* GdkPixbuf library - GIF image loader
  *
  * Copyright (C) 1999 Mark Crichton
- * Author: Mark Crichton <crichton@gimp.org>
+ * Copyright (C) 1999 The Free Software Foundation
+ *
+ * Authors: Jonathan Blandford <jrb@redhat.com>
+ *          Adapted from the gimp gif filter written by Adam Moss <adam@gimp.org>
+ *          Gimp work based on earlier work.
+ *          Permission to relicense under the LGPL obtained.
  *
  * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
+ * modify it under the terms of the GNU Lesser 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.
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser 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.
+ */
+
+/* This loader is very hairy code.
+ *
+ * The main loop was not designed for incremental loading, so when it was hacked
+ * in it got a bit messy.  Basicly, every function is written to expect a failed
+ * read_gif, and lets you call it again assuming that the bytes are there.
  *
- * 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.
+ * Return vals.
+ * Unless otherwise specified, these are the return vals for most functions:
  *
+ *  0 -> success
+ * -1 -> more bytes needed.
+ * -2 -> failure; abort the load
+ * -3 -> control needs to be passed back to the main loop
+ *        \_ (most of the time returning 0 will get this, but not always)
+ *
+ * >1 -> for functions that get a guchar, the char will be returned.
+ *
+ * -jrb (11/03/1999)
+ */
+
+/*
+ * If you have any images that crash this code, please, please let me know and
+ * send them to me.
+ *                                            <jrb@redhat.com>
  */
 
-#include <config.h>
+\f
+
+#include "config.h"
 #include <stdio.h>
-#include <glib.h>
-#include "gdk-pixbuf.h"
+#include <string.h>
+#include <errno.h>
+#include "gdk-pixbuf-private.h"
 #include "gdk-pixbuf-io.h"
-#include <gif_lib.h>
+#include "io-gif-animation.h"
+
+\f
+
+#undef DUMP_IMAGE_DETAILS 
+#undef IO_GIFDEBUG
+
+#define MAXCOLORMAPSIZE  256
+#define MAX_LZW_BITS     12
+
+#define INTERLACE          0x40
+#define LOCALCOLORMAP      0x80
+#define BitSet(byte, bit)  (((byte) & (bit)) == (bit))
+#define LM_to_uint(a,b)         (((b)<<8)|(a))
+
+\f
+
+typedef unsigned char CMap[3][MAXCOLORMAPSIZE];
+
+/* Possible states we can be in. */
+enum {
+       GIF_START,
+       GIF_GET_COLORMAP,
+       GIF_GET_NEXT_STEP,
+       GIF_GET_FRAME_INFO,
+       GIF_GET_EXTENSION,
+       GIF_GET_COLORMAP2,
+       GIF_PREPARE_LZW,
+       GIF_LZW_FILL_BUFFER,
+       GIF_LZW_CLEAR_CODE,
+       GIF_GET_LZW,
+       GIF_DONE
+};
+
+
+typedef struct _Gif89 Gif89;
+struct _Gif89
+{
+       int transparent;
+       int delay_time;
+       int input_flag;
+       int disposal;
+};
+
+typedef struct _GifContext GifContext;
+struct _GifContext
+{
+       int state; /* really only relevant for progressive loading */
+       unsigned int width;
+       unsigned int height;
+
+        gboolean has_global_cmap;
+
+        CMap global_color_map;
+        gint global_colormap_size;
+        unsigned int global_bit_pixel;
+       unsigned int global_color_resolution;
+        unsigned int background_index;
+        gboolean stop_after_first_frame;
+
+        gboolean frame_cmap_active;
+        CMap frame_color_map;
+        gint frame_colormap_size;
+        unsigned int frame_bit_pixel;
+
+       unsigned int aspect_ratio;
+       GdkPixbufGifAnim *animation;
+       GdkPixbufFrame *frame;
+       Gif89 gif89;
+
+       /* stuff per frame. */
+       int frame_len;
+       int frame_height;
+       int frame_interlace;
+       int x_offset;
+       int y_offset;
+
+       /* Static read only */
+       FILE *file;
+
+       /* progressive read, only. */
+       GdkPixbufModulePreparedFunc prepare_func;
+       GdkPixbufModuleUpdatedFunc update_func;
+       gpointer user_data;
+        guchar *buf;
+       guint ptr;
+       guint size;
+       guint amount_needed;
+
+       /* extension context */
+       guchar extension_label;
+       guchar extension_flag;
+        gboolean in_loop_extension;
+
+       /* get block context */
+       guchar block_count;
+       guchar block_buf[280];
+       gint block_ptr;
+
+       int old_state; /* used by lzw_fill buffer */
+       /* get_code context */
+       int code_curbit;
+       int code_lastbit;
+       int code_done;
+       int code_last_byte;
+       int lzw_code_pending;
+
+       /* lzw context */
+       gint lzw_fresh;
+       gint lzw_code_size;
+       guchar lzw_set_code_size;
+       gint lzw_max_code;
+       gint lzw_max_code_size;
+       gint lzw_firstcode;
+       gint lzw_oldcode;
+       gint lzw_clear_code;
+       gint lzw_end_code;
+       gint *lzw_sp;
+
+       gint lzw_table[2][(1 << MAX_LZW_BITS)];
+       gint lzw_stack[(1 << (MAX_LZW_BITS)) * 2 + 1];
+
+       /* painting context */
+       gint draw_xpos;
+       gint draw_ypos;
+       gint draw_pass;
+
+        /* error pointer */
+        GError **error;
+};
+
+static int GetDataBlock (GifContext *, unsigned char *);
+
+\f
+
+#ifdef IO_GIFDEBUG
+static int count = 0;
+#endif
+
+/* Returns TRUE if read is OK,
+ * FALSE if more memory is needed. */
+static gboolean
+gif_read (GifContext *context, guchar *buffer, size_t len)
+{
+       gboolean retval;
+#ifdef IO_GIFDEBUG
+       gint i;
+#endif
+       if (context->file) {
+#ifdef IO_GIFDEBUG
+               count += len;
+               g_print ("Fsize :%d\tcount :%d\t", len, count);
+#endif
+               retval = (fread(buffer, len, 1, context->file) != 0);
+
+                if (!retval && ferror (context->file)) {
+                        gint save_errno = errno;
+                        g_set_error (context->error,
+                                     G_FILE_ERROR,
+                                     g_file_error_from_errno (save_errno),
+                                     _("Failure reading GIF: %s"), 
+                                     g_strerror (save_errno));
+                }
+                
+#ifdef IO_GIFDEBUG
+               if (len < 100) {
+                       for (i = 0; i < len; i++)
+                               g_print ("%d ", buffer[i]);
+               }
+               g_print ("\n");
+#endif
+                
+               return retval;
+       } else {
+#ifdef IO_GIFDEBUG
+/*             g_print ("\tlooking for %d bytes.  size == %d, ptr == %d\n", len, context->size, context->ptr); */
+#endif
+               if ((context->size - context->ptr) >= len) {
+#ifdef IO_GIFDEBUG
+                       count += len;
+#endif
+                       memcpy (buffer, context->buf + context->ptr, len);
+                       context->ptr += len;
+                       context->amount_needed = 0;
+#ifdef IO_GIFDEBUG
+                       g_print ("Psize :%d\tcount :%d\t", len, count);
+                       if (len < 100) {
+                               for (i = 0; i < len; i++)
+                                       g_print ("%d ", buffer[i]);
+                       }
+                       g_print ("\n");
+#endif
+                       return TRUE;
+               }
+               context->amount_needed = len - (context->size - context->ptr);
+       }
+       return FALSE;
+}
+
+/* Changes the stage to be GIF_GET_COLORMAP */
+static void
+gif_set_get_colormap (GifContext *context)
+{
+       context->global_colormap_size = 0;
+       context->state = GIF_GET_COLORMAP;
+}
+
+static void
+gif_set_get_colormap2 (GifContext *context)
+{
+       context->frame_colormap_size = 0;
+       context->state = GIF_GET_COLORMAP2;
+}
+
+static gint
+gif_get_colormap (GifContext *context)
+{
+       unsigned char rgb[3];
+
+       while (context->global_colormap_size < context->global_bit_pixel) {
+               if (!gif_read (context, rgb, sizeof (rgb))) {
+                       return -1;
+               }
+
+               context->global_color_map[0][context->global_colormap_size] = rgb[0];
+               context->global_color_map[1][context->global_colormap_size] = rgb[1];
+               context->global_color_map[2][context->global_colormap_size] = rgb[2];
+
+                if (context->global_colormap_size == context->background_index) {
+                        context->animation->bg_red = rgb[0];
+                        context->animation->bg_green = rgb[1];
+                        context->animation->bg_blue = rgb[2];
+                }
+
+               context->global_colormap_size ++;
+       }
+
+       return 0;
+}
+
+
+static gint
+gif_get_colormap2 (GifContext *context)
+{
+       unsigned char rgb[3];
+
+       while (context->frame_colormap_size < context->frame_bit_pixel) {
+               if (!gif_read (context, rgb, sizeof (rgb))) {
+                       return -1;
+               }
+
+               context->frame_color_map[0][context->frame_colormap_size] = rgb[0];
+               context->frame_color_map[1][context->frame_colormap_size] = rgb[1];
+               context->frame_color_map[2][context->frame_colormap_size] = rgb[2];
+
+               context->frame_colormap_size ++;
+       }
+
+       return 0;
+}
+
+/*
+ * in order for this function to work, we need to perform some black magic.
+ * We want to return -1 to let the calling function know, as before, that it needs
+ * more bytes.  If we return 0, we were able to successfully read all block->count bytes.
+ * Problem is, we don't want to reread block_count every time, so we check to see if
+ * context->block_count is 0 before we read in the function.
+ *
+ * As a result, context->block_count MUST be 0 the first time the get_data_block is called
+ * within a context, and cannot be 0 the second time it's called.
+ */
+
+static int
+get_data_block (GifContext *context,
+               unsigned char *buf,
+               gint *empty_block)
+{
+
+       if (context->block_count == 0) {
+               if (!gif_read (context, &context->block_count, 1)) {
+                       return -1;
+               }
+       }
+
+       if (context->block_count == 0)
+               if (empty_block) {
+                       *empty_block = TRUE;
+                       return 0;
+               }
+
+       if (!gif_read (context, buf, context->block_count)) {
+               return -1;
+       }
+
+       return 0;
+}
+
+static void
+gif_set_get_extension (GifContext *context)
+{
+       context->state = GIF_GET_EXTENSION;
+       context->extension_flag = TRUE;
+       context->extension_label = 0;
+       context->block_count = 0;
+       context->block_ptr = 0;
+}
+
+static int
+gif_get_extension (GifContext *context)
+{
+       gint retval;
+       gint empty_block = FALSE;
+
+       if (context->extension_flag) {
+               if (context->extension_label == 0) {
+                       /* I guess bad things can happen if we have an extension of 0 )-: */
+                       /* I should look into this sometime */
+                       if (!gif_read (context, & context->extension_label , 1)) {
+                               return -1;
+                       }
+               }
+
+               switch (context->extension_label) {
+                case 0xf9:                     /* Graphic Control Extension */
+                        retval = get_data_block (context, (unsigned char *) context->block_buf, NULL);
+                       if (retval != 0)
+                               return retval;
+
+                       if (context->frame == NULL) {
+                               /* I only want to set the transparency if I haven't
+                                * created the frame yet.
+                                 */
+                               context->gif89.disposal = (context->block_buf[0] >> 2) & 0x7;
+                               context->gif89.input_flag = (context->block_buf[0] >> 1) & 0x1;
+                               context->gif89.delay_time = LM_to_uint (context->block_buf[1], context->block_buf[2]);
+                               
+                               if ((context->block_buf[0] & 0x1) != 0) {
+                                       context->gif89.transparent = context->block_buf[3];
+                               } else {
+                                       context->gif89.transparent = -1;
+                               }
+                       }
+
+                       /* Now we've successfully loaded this one, we continue on our way */
+                       context->block_count = 0;
+                       context->extension_flag = FALSE;
+                       break;
+                case 0xff: /* application extension */
+                        if (!context->in_loop_extension) { 
+                                retval = get_data_block (context, (unsigned char *) context->block_buf, NULL);
+                                if (retval != 0)
+                                        return retval;
+                                if (!strncmp ((gchar *)context->block_buf, "NETSCAPE2.0", 11) ||
+                                    !strncmp ((gchar *)context->block_buf, "ANIMEXTS1.0", 11)) {
+                                        context->in_loop_extension = TRUE;
+                                }
+                                context->block_count = 0;
+                        }
+                        if (context->in_loop_extension) {
+                                do {
+                                        retval = get_data_block (context, (unsigned char *) context->block_buf, &empty_block);
+                                        if (retval != 0)
+                                                return retval;
+                                        if (context->block_buf[0] == 0x01) {
+                                                context->animation->loop = context->block_buf[1] + (context->block_buf[2] << 8);
+                                                if (context->animation->loop != 0) 
+                                                        context->animation->loop++;
+                                        }
+                                        context->block_count = 0;
+                                }
+                                while (!empty_block);
+                                context->in_loop_extension = FALSE;
+                                context->extension_flag = FALSE;
+                                return 0;
+                        }
+                       break;                          
+               default:
+                       /* Unhandled extension */
+                       break;
+               }
+       }
+       /* read all blocks, until I get an empty block, in case there was an extension I didn't know about. */
+       do {
+               retval = get_data_block (context, (unsigned char *) context->block_buf, &empty_block);
+               if (retval != 0)
+                       return retval;
+               context->block_count = 0;
+       } while (!empty_block);
+
+       return 0;
+}
+
+static int ZeroDataBlock = FALSE;
+
+static int
+GetDataBlock (GifContext *context,
+             unsigned char *buf)
+{
+/*     unsigned char count; */
+
+       if (!gif_read (context, &context->block_count, 1)) {
+               /*g_message (_("GIF: error in getting DataBlock size\n"));*/
+               return -1;
+       }
+
+       ZeroDataBlock = context->block_count == 0;
+
+       if ((context->block_count != 0) && (!gif_read (context, buf, context->block_count))) {
+               /*g_message (_("GIF: error in reading DataBlock\n"));*/
+               return -1;
+       }
+
+       return context->block_count;
+}
+
+
+static void
+gif_set_lzw_fill_buffer (GifContext *context)
+{
+       context->block_count = 0;
+       context->old_state = context->state;
+       context->state = GIF_LZW_FILL_BUFFER;
+}
+
+static int
+gif_lzw_fill_buffer (GifContext *context)
+{
+       gint retval;
+
+       if (context->code_done) {
+               if (context->code_curbit >= context->code_lastbit) {
+                        g_set_error_literal (context->error,
+                                             GDK_PIXBUF_ERROR,
+                                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                                             _("GIF file was missing some data (perhaps it was truncated somehow?)"));
+
+                       return -2;
+               }
+                /* Is this supposed to be an error or what? */
+               /* g_message ("trying to read more data after we've done stuff\n"); */
+                g_set_error (context->error,
+                             GDK_PIXBUF_ERROR,
+                             GDK_PIXBUF_ERROR_FAILED,
+                             _("Internal error in the GIF loader (%s)"),
+                             G_STRLOC);
+                
+               return -2;
+       }
+
+       context->block_buf[0] = context->block_buf[context->code_last_byte - 2];
+       context->block_buf[1] = context->block_buf[context->code_last_byte - 1];
+
+       retval = get_data_block (context, &context->block_buf[2], NULL);
+
+       if (retval == -1)
+               return -1;
+
+       if (context->block_count == 0)
+               context->code_done = TRUE;
+
+       context->code_last_byte = 2 + context->block_count;
+       context->code_curbit = (context->code_curbit - context->code_lastbit) + 16;
+       context->code_lastbit = (2 + context->block_count) * 8;
+
+       context->state = context->old_state;
+       return 0;
+}
+
+static int
+get_code (GifContext *context,
+         int   code_size)
+{
+       int i, j, ret;
+
+       if ((context->code_curbit + code_size) >= context->code_lastbit){
+               gif_set_lzw_fill_buffer (context);
+               return -3;
+       }
+
+       ret = 0;
+       for (i = context->code_curbit, j = 0; j < code_size; ++i, ++j)
+               ret |= ((context->block_buf[i / 8] & (1 << (i % 8))) != 0) << j;
+
+       context->code_curbit += code_size;
+
+       return ret;
+}
+
+
+static void
+set_gif_lzw_clear_code (GifContext *context)
+{
+       context->state = GIF_LZW_CLEAR_CODE;
+       context->lzw_code_pending = -1;
+}
+
+static int
+gif_lzw_clear_code (GifContext *context)
+{
+       gint code;
+
+       code = get_code (context, context->lzw_code_size);
+       if (code == -3)
+               return -0;
+
+       context->lzw_firstcode = context->lzw_oldcode = code;
+       context->lzw_code_pending = code;
+       context->state = GIF_GET_LZW;
+       return 0;
+}
+
+#define CHECK_LZW_SP() G_STMT_START {                                           \
+        if ((guchar *)context->lzw_sp >=                                        \
+            (guchar *)context->lzw_stack + sizeof (context->lzw_stack)) {       \
+                 g_set_error_literal (context->error,                           \
+                                      GDK_PIXBUF_ERROR,                         \
+                                      GDK_PIXBUF_ERROR_CORRUPT_IMAGE,           \
+                                      _("Stack overflow"));                     \
+                return -2;                                                      \
+        }                                                                       \
+} G_STMT_END
+
+static int
+lzw_read_byte (GifContext *context)
+{
+       int code, incode;
+       gint retval;
+       gint my_retval;
+       register int i;
+
+       if (context->lzw_code_pending != -1) {
+               retval = context->lzw_code_pending;
+               context->lzw_code_pending = -1;
+               return retval;
+       }
+
+       if (context->lzw_fresh) {
+               context->lzw_fresh = FALSE;
+               do {
+                       retval = get_code (context, context->lzw_code_size);
+                       if (retval < 0) {
+                               return retval;
+                       }
+
+                       context->lzw_firstcode = context->lzw_oldcode = retval;
+               } while (context->lzw_firstcode == context->lzw_clear_code);
+               return context->lzw_firstcode;
+       }
+
+       if (context->lzw_sp > context->lzw_stack) {
+               my_retval = *--(context->lzw_sp);
+               return my_retval;
+       }
+
+       while ((code = get_code (context, context->lzw_code_size)) >= 0) {
+               if (code == context->lzw_clear_code) {
+                       for (i = 0; i < context->lzw_clear_code; ++i) {
+                               context->lzw_table[0][i] = 0;
+                               context->lzw_table[1][i] = i;
+                       }
+                       for (; i < (1 << MAX_LZW_BITS); ++i)
+                               context->lzw_table[0][i] = context->lzw_table[1][i] = 0;
+                       context->lzw_code_size = context->lzw_set_code_size + 1;
+                       context->lzw_max_code_size = 2 * context->lzw_clear_code;
+                       context->lzw_max_code = context->lzw_clear_code + 2;
+                       context->lzw_sp = context->lzw_stack;
+
+                       set_gif_lzw_clear_code (context);
+                       return -3;
+               } else if (code == context->lzw_end_code) {
+                       int count;
+                       unsigned char buf[260];
+
+                        /*  FIXME - we should handle this case */
+                        g_set_error_literal (context->error,
+                                             GDK_PIXBUF_ERROR,
+                                             GDK_PIXBUF_ERROR_FAILED,
+                                             _("GIF image loader cannot understand this image."));
+                        return -2;
+                        
+                       if (ZeroDataBlock) {
+                               return -2;
+                       }
+
+                       while ((count = GetDataBlock (context, buf)) > 0)
+                               ;
+
+                       if (count != 0) {
+                               /*g_print (_("GIF: missing EOD in data stream (common occurence)"));*/
+                               return -2;
+                       }
+               }
+
+               incode = code;
+
+               if (code >= context->lzw_max_code) {
+                        CHECK_LZW_SP ();
+                       *(context->lzw_sp)++ = context->lzw_firstcode;
+                       code = context->lzw_oldcode;
+               }
+
+               while (code >= context->lzw_clear_code) {
+                        if (code >= (1 << MAX_LZW_BITS)) {
+                                g_set_error_literal (context->error,
+                                                     GDK_PIXBUF_ERROR,
+                                                     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                                                     _("Bad code encountered"));
+                               return -2;
+                        }
+                        CHECK_LZW_SP ();
+                       *(context->lzw_sp)++ = context->lzw_table[1][code];
+
+                       if (code == context->lzw_table[0][code]) {
+                                g_set_error_literal (context->error,
+                                                     GDK_PIXBUF_ERROR,
+                                                     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                                                     _("Circular table entry in GIF file"));
+                               return -2;
+                       }
+                       code = context->lzw_table[0][code];
+               }
+
+                CHECK_LZW_SP ();
+               *(context->lzw_sp)++ = context->lzw_firstcode = context->lzw_table[1][code];
+
+               if ((code = context->lzw_max_code) < (1 << MAX_LZW_BITS)) {
+                       context->lzw_table[0][code] = context->lzw_oldcode;
+                       context->lzw_table[1][code] = context->lzw_firstcode;
+                       ++context->lzw_max_code;
+                       if ((context->lzw_max_code >= context->lzw_max_code_size) &&
+                           (context->lzw_max_code_size < (1 << MAX_LZW_BITS))) {
+                               context->lzw_max_code_size *= 2;
+                               ++context->lzw_code_size;
+                       }
+               }
+
+               context->lzw_oldcode = incode;
+
+               if (context->lzw_sp > context->lzw_stack) {
+                       my_retval = *--(context->lzw_sp);
+                       return my_retval;
+               }
+       }
+       return code;
+}
+
+static void
+gif_set_get_lzw (GifContext *context)
+{
+       context->state = GIF_GET_LZW;
+       context->draw_xpos = 0;
+       context->draw_ypos = 0;
+       context->draw_pass = 0;
+}
+
+static void
+gif_fill_in_pixels (GifContext *context, guchar *dest, gint offset, guchar v)
+{
+       guchar *pixel = NULL;
+        guchar (*cmap)[MAXCOLORMAPSIZE];
 
+        if (context->frame_cmap_active)
+                cmap = context->frame_color_map;
+        else
+                cmap = context->global_color_map;
+        
+       if (context->gif89.transparent != -1) {
+               pixel = dest + (context->draw_ypos + offset) * gdk_pixbuf_get_rowstride (context->frame->pixbuf) + context->draw_xpos * 4;
+               *pixel = cmap [0][(guchar) v];
+               *(pixel+1) = cmap [1][(guchar) v];
+               *(pixel+2) = cmap [2][(guchar) v];
+               *(pixel+3) = (guchar) ((v == context->gif89.transparent) ? 0 : 255);
+       } else {
+               pixel = dest + (context->draw_ypos + offset) * gdk_pixbuf_get_rowstride (context->frame->pixbuf) + context->draw_xpos * 3;
+               *pixel = cmap [0][(guchar) v];
+               *(pixel+1) = cmap [1][(guchar) v];
+               *(pixel+2) = cmap [2][(guchar) v];
+       }
+}
+
+
+/* only called if progressive and interlaced */
+static void
+gif_fill_in_lines (GifContext *context, guchar *dest, guchar v)
+{
+       switch (context->draw_pass) {
+       case 0:
+               if (context->draw_ypos > 4) {
+                       gif_fill_in_pixels (context, dest, -4, v);
+                       gif_fill_in_pixels (context, dest, -3, v);
+               }
+               if (context->draw_ypos < (context->frame_height - 4)) {
+                       gif_fill_in_pixels (context, dest, 3, v);
+                       gif_fill_in_pixels (context, dest, 4, v);
+               }
+               /* we don't need a break here.  We draw the outer pixels first, then the
+                * inner ones, then the innermost ones.  case 0 needs to draw all 3 bands.
+                * case 1, just the last two, and case 2 just draws the last one*/
+       case 1:
+               if (context->draw_ypos > 2)
+                       gif_fill_in_pixels (context, dest, -2, v);
+               if (context->draw_ypos < (context->frame_height - 2))
+                       gif_fill_in_pixels (context, dest, 2, v);
+               /* no break as above. */
+       case 2:
+               if (context->draw_ypos > 1)
+                       gif_fill_in_pixels (context, dest, -1, v);
+               if (context->draw_ypos < (context->frame_height - 1))
+                       gif_fill_in_pixels (context, dest, 1, v);
+       case 3:
+       default:
+               break;
+       }
+}
+
+/* Clips a rectancle to the base dimensions. Returns TRUE if the clipped rectangle is non-empty. */
+static gboolean
+clip_frame (GifContext *context, 
+            gint       *x, 
+            gint       *y, 
+            gint       *width, 
+            gint       *height)
+{
+        gint orig_x, orig_y;
+        
+        orig_x = *x;
+        orig_y = *y;
+       *x = MAX (0, *x);
+       *y = MAX (0, *y);
+       *width = MIN (context->width, orig_x + *width) - *x;
+       *height = MIN (context->height, orig_y + *height) - *y;
+
+       if (*width > 0 && *height > 0)
+               return TRUE;
+
+       /* The frame is completely off-bounds */
+
+       *x = 0;
+       *y = 0;
+       *width = 0;
+       *height = 0;
+
+        return FALSE;
+}
+
+/* Call update_func on the given rectangle, unless it is completely off-bounds */
+static void
+maybe_update (GifContext *context,
+              gint        x,
+              gint        y,
+              gint        width,
+              gint        height)
+{
+        if (clip_frame (context, &x, &y, &width, &height))
+                (*context->update_func) (context->frame->pixbuf, 
+                                         x, y, width, height,
+                                         context->user_data);
+}
+
+static int
+gif_get_lzw (GifContext *context)
+{
+       guchar *dest, *temp;
+       gint lower_bound, upper_bound; /* bounds for emitting the area_updated signal */
+       gboolean bound_flag;
+       gint first_pass; /* bounds for emitting the area_updated signal */
+       gint v;
+
+       if (context->frame == NULL) {
+                context->frame = g_new (GdkPixbufFrame, 1);
+
+                context->frame->composited = NULL;
+                context->frame->revert = NULL;
+                
+                if (context->frame_len == 0 || context->frame_height == 0) {
+                        /* An empty frame, we just output a single transparent
+                         * pixel at (0, 0).
+                         */
+                        context->x_offset = 0;
+                        context->y_offset = 0;
+                        context->frame_len = 1;
+                        context->frame_height = 1;
+                        context->frame->pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, TRUE, 8, 1, 1);
+                        if (context->frame->pixbuf) {
+                                guchar *pixels;
+
+                                pixels = gdk_pixbuf_get_pixels (context->frame->pixbuf);
+                                pixels[0] = 0;
+                                pixels[1] = 0;
+                                pixels[2] = 0;
+                                pixels[3] = 0;
+                        }
+                } else
+                        context->frame->pixbuf =
+                                gdk_pixbuf_new (GDK_COLORSPACE_RGB,
+                                                TRUE,
+                                                8,
+                                                context->frame_len,
+                                                context->frame_height);
+                if (!context->frame->pixbuf) {
+                        g_free (context->frame);
+                        g_set_error_literal (context->error,
+                                             GDK_PIXBUF_ERROR,
+                                             GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
+                                             _("Not enough memory to load GIF file"));
+                        return -2;
+                }
+
+                context->frame->x_offset = context->x_offset;
+                context->frame->y_offset = context->y_offset;
+                context->frame->need_recomposite = TRUE;
+                
+                /* GIF delay is in hundredths, we want thousandths */
+                context->frame->delay_time = context->gif89.delay_time * 10;
+
+                /* GIFs with delay time 0 are mostly broken, but they
+                 * just want a default, "not that fast" delay.
+                 */
+                if (context->frame->delay_time == 0)
+                        context->frame->delay_time = 100;
+
+                /* No GIFs gets to play faster than 50 fps. They just
+                 * lock up poor gtk.
+                 */
+                if (context->frame->delay_time < 20)
+                        context->frame->delay_time = 20; /* 20 = "fast" */
+                
+                context->frame->elapsed = context->animation->total_time;
+                context->animation->total_time += context->frame->delay_time;                
+                
+                switch (context->gif89.disposal) {
+                case 0:
+                case 1:
+                        context->frame->action = GDK_PIXBUF_FRAME_RETAIN;
+                        break;
+                case 2:
+                        context->frame->action = GDK_PIXBUF_FRAME_DISPOSE;
+                        break;
+                case 3:
+                        context->frame->action = GDK_PIXBUF_FRAME_REVERT;
+                        break;
+                default:
+                        context->frame->action = GDK_PIXBUF_FRAME_RETAIN;
+                        break;
+                }
+
+                context->frame->bg_transparent = (context->gif89.transparent == context->background_index);
+                
+                context->animation->n_frames ++;
+                context->animation->frames = g_list_append (context->animation->frames, context->frame);
+
+                /* Only call prepare_func for the first frame */
+               if (context->animation->frames->next == NULL) { 
+                        if (context->animation->width == 0 )
+                                context->animation->width = gdk_pixbuf_get_width(context->frame->pixbuf);
+                        if (context->animation->height == 0)
+                                context->animation->height = gdk_pixbuf_get_height (context->frame->pixbuf);
+
+                        if (context->prepare_func)
+                                (* context->prepare_func) (context->frame->pixbuf,
+                                                           GDK_PIXBUF_ANIMATION (context->animation),
+                                                           context->user_data);
+                } else {
+                        /* Otherwise init frame with last frame */
+                        GList *link;
+                        GdkPixbufFrame *prev_frame;
+                        gint x, y, w, h;
+                        
+                        link = g_list_find (context->animation->frames, context->frame);
+
+                        prev_frame = link->prev->data;
+
+                        gdk_pixbuf_gif_anim_frame_composite (context->animation, prev_frame);
+
+                        /* Composite failed */
+                        if (prev_frame->composited == NULL) {
+                                GdkPixbufFrame *frame = NULL;
+                                link = g_list_first (context->animation->frames);
+                                while (link != NULL) {
+                                        frame = (GdkPixbufFrame *)link->data;
+                                        if (frame != NULL) {
+                                                if (frame->pixbuf != NULL)
+                                                        g_object_unref (frame->pixbuf);
+                                                if (frame->composited != NULL)
+                                                        g_object_unref (frame->composited);
+                                                if (frame->revert != NULL)
+                                                        g_object_unref (frame->revert);
+                                                g_free (frame);
+                                        }
+                                        link = link->next;
+                                }
+                                
+                                g_list_free (context->animation->frames);
+                                context->animation->frames = NULL;
+                                
+                                g_set_error_literal (context->error,
+                                                     GDK_PIXBUF_ERROR,
+                                                     GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
+                                                     _("Not enough memory to composite a frame in GIF file"));
+                                return -2;
+                        }
+                    
+                        x = context->frame->x_offset;
+                        y = context->frame->y_offset;
+                        w = gdk_pixbuf_get_width (context->frame->pixbuf);
+                        h = gdk_pixbuf_get_height (context->frame->pixbuf);
+                        if (clip_frame (context, &x, &y, &w, &h))
+                                gdk_pixbuf_copy_area (prev_frame->composited,
+                                                      x, y, w, h,
+                                                      context->frame->pixbuf,
+                                                      0, 0);
+                }
+        }
+
+       dest = gdk_pixbuf_get_pixels (context->frame->pixbuf);
+
+       bound_flag = FALSE;
+       lower_bound = upper_bound = context->draw_ypos;
+       first_pass = context->draw_pass;
+
+       while (TRUE) {
+                guchar (*cmap)[MAXCOLORMAPSIZE];
+
+                if (context->frame_cmap_active)
+                        cmap = context->frame_color_map;
+                else
+                        cmap = context->global_color_map;
+                
+               v = lzw_read_byte (context);
+               if (v < 0) {
+                       goto finished_data;
+               }
+               bound_flag = TRUE;
+
+                g_assert (gdk_pixbuf_get_has_alpha (context->frame->pixbuf));
+                
+                temp = dest + context->draw_ypos * gdk_pixbuf_get_rowstride (context->frame->pixbuf) + context->draw_xpos * 4;
+                *temp = cmap [0][(guchar) v];
+                *(temp+1) = cmap [1][(guchar) v];
+                *(temp+2) = cmap [2][(guchar) v];
+                *(temp+3) = (guchar) ((v == context->gif89.transparent) ? 0 : 255);
+
+               if (context->prepare_func && context->frame_interlace)
+                       gif_fill_in_lines (context, dest, v);
+
+               context->draw_xpos++;
+                
+               if (context->draw_xpos == context->frame_len) {
+                       context->draw_xpos = 0;
+                       if (context->frame_interlace) {
+                               switch (context->draw_pass) {
+                               case 0:
+                               case 1:
+                                       context->draw_ypos += 8;
+                                       break;
+                               case 2:
+                                       context->draw_ypos += 4;
+                                       break;
+                               case 3:
+                                       context->draw_ypos += 2;
+                                       break;
+                               }
+
+                               if (context->draw_ypos >= context->frame_height) {
+                                       context->draw_pass++;
+                                       switch (context->draw_pass) {
+                                       case 1:
+                                               context->draw_ypos = 4;
+                                               break;
+                                       case 2:
+                                               context->draw_ypos = 2;
+                                               break;
+                                       case 3:
+                                               context->draw_ypos = 1;
+                                               break;
+                                       default:
+                                               goto done;
+                                       }
+                               }
+                       } else {
+                               context->draw_ypos++;
+                       }
+                       if (context->draw_pass != first_pass) {
+                               if (context->draw_ypos > lower_bound) {
+                                       lower_bound = 0;
+                                       upper_bound = context->frame_height;
+                               } else {
+                                        
+                               }
+                       } else
+                               upper_bound = context->draw_ypos;
+               }
+               if (context->draw_ypos >= context->frame_height)
+                       break;
+       }
+
+ done:
+
+        context->state = GIF_GET_NEXT_STEP;
+
+        v = 0;
+
+ finished_data:
+        
+        if (bound_flag)
+                context->frame->need_recomposite = TRUE;
+        
+       if (bound_flag && context->update_func) {
+               if (lower_bound <= upper_bound && first_pass == context->draw_pass) {
+                        maybe_update (context, 
+                                      context->frame->x_offset,
+                                      context->frame->y_offset + lower_bound,
+                                      gdk_pixbuf_get_width (context->frame->pixbuf),
+                                      upper_bound - lower_bound);
+               } else {
+                       if (lower_bound <= upper_bound) {
+                                maybe_update (context,
+                                              context->frame->x_offset,
+                                              context->frame->y_offset,
+                                              gdk_pixbuf_get_width (context->frame->pixbuf),
+                                              gdk_pixbuf_get_height (context->frame->pixbuf));
+                       } else {
+                                maybe_update (context,
+                                              context->frame->x_offset,
+                                              context->frame->y_offset,
+                                              gdk_pixbuf_get_width (context->frame->pixbuf),
+                                              upper_bound);
+                                maybe_update (context,
+                                              context->frame->x_offset,
+                                              context->frame->y_offset + lower_bound,
+                                              gdk_pixbuf_get_width (context->frame->pixbuf),
+                                              gdk_pixbuf_get_height (context->frame->pixbuf) - lower_bound);
+                       }
+               }
+       }
+
+       if (context->state == GIF_GET_NEXT_STEP) {
+                /* Will be freed with context->animation, we are just
+                 * marking that we're done with it (no current frame)
+                 */
+               context->frame = NULL;
+                context->frame_cmap_active = FALSE;
+
+                if (context->stop_after_first_frame)
+                        context->state =  GIF_DONE;
+       }
+       
+       return v;
+}
+
+static void
+gif_set_prepare_lzw (GifContext *context)
+{
+       context->state = GIF_PREPARE_LZW;
+       context->lzw_code_pending = -1;
+}
+static int
+gif_prepare_lzw (GifContext *context)
+{
+       gint i;
+
+       if (!gif_read (context, &(context->lzw_set_code_size), 1)) {
+               /*g_message (_("GIF: EOF / read error on image data\n"));*/
+               return -1;
+       }
+        
+        if (context->lzw_set_code_size > MAX_LZW_BITS) {
+                g_set_error_literal (context->error,
+                                     GDK_PIXBUF_ERROR,
+                                     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                                     _("GIF image is corrupt (incorrect LZW compression)"));
+                return -2;
+        }
+
+       context->lzw_code_size = context->lzw_set_code_size + 1;
+       context->lzw_clear_code = 1 << context->lzw_set_code_size;
+       context->lzw_end_code = context->lzw_clear_code + 1;
+       context->lzw_max_code_size = 2 * context->lzw_clear_code;
+       context->lzw_max_code = context->lzw_clear_code + 2;
+       context->lzw_fresh = TRUE;
+       context->code_curbit = 0;
+       context->code_lastbit = 0;
+       context->code_last_byte = 0;
+       context->code_done = FALSE;
+
+        g_assert (context->lzw_clear_code <= 
+                  G_N_ELEMENTS (context->lzw_table[0]));
+
+       for (i = 0; i < context->lzw_clear_code; ++i) {
+               context->lzw_table[0][i] = 0;
+               context->lzw_table[1][i] = i;
+       }
+       for (; i < (1 << MAX_LZW_BITS); ++i)
+               context->lzw_table[0][i] = context->lzw_table[1][0] = 0;
+
+       context->lzw_sp = context->lzw_stack;
+       gif_set_get_lzw (context);
+
+       return 0;
+}
+
+/* needs 13 bytes to proceed. */
+static gint
+gif_init (GifContext *context)
+{
+       unsigned char buf[16];
+       char version[4];
+
+       if (!gif_read (context, buf, 6)) {
+               /* Unable to read magic number,
+                 * gif_read() should have set error
+                 */
+               return -1;
+       }
+
+       if (strncmp ((char *) buf, "GIF", 3) != 0) {
+               /* Not a GIF file */
+                g_set_error_literal (context->error,
+                                     GDK_PIXBUF_ERROR,
+                                     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                                     _("File does not appear to be a GIF file"));
+               return -2;
+       }
+
+       strncpy (version, (char *) buf + 3, 3);
+       version[3] = '\0';
+
+       if ((strcmp (version, "87a") != 0) && (strcmp (version, "89a") != 0)) {
+               /* bad version number, not '87a' or '89a' */
+                g_set_error (context->error,
+                             GDK_PIXBUF_ERROR,
+                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                             _("Version %s of the GIF file format is not supported"),
+                             version);
+               return -2;
+       }
+
+       /* read the screen descriptor */
+       if (!gif_read (context, buf, 7)) {
+               /* Failed to read screen descriptor, error set */
+               return -1;
+       }
+
+       context->width = LM_to_uint (buf[0], buf[1]);
+       context->height = LM_to_uint (buf[2], buf[3]);
+        /* The 4th byte is
+         * high bit: whether to use the background index
+         * next 3:   color resolution
+         * next:     whether colormap is sorted by priority of allocation
+         * last 3:   size of colormap
+         */
+       context->global_bit_pixel = 2 << (buf[4] & 0x07);
+       context->global_color_resolution = (((buf[4] & 0x70) >> 3) + 1);
+        context->has_global_cmap = (buf[4] & 0x80) != 0;
+       context->background_index = buf[5];
+       context->aspect_ratio = buf[6];
+
+        /* Use background of transparent black as default, though if
+         * one isn't set explicitly no one should ever use it.
+         */
+        context->animation->bg_red = 0;
+        context->animation->bg_green = 0;
+        context->animation->bg_blue = 0;
+
+        context->animation->width = context->width;
+        context->animation->height = context->height;
+
+       if (context->has_global_cmap) {
+               gif_set_get_colormap (context);
+       } else {
+               context->state = GIF_GET_NEXT_STEP;
+       }
+
+#ifdef DUMP_IMAGE_DETAILS
+        g_print (">Image width: %d height: %d global_cmap: %d background: %d\n",
+                 context->width, context->height, context->has_global_cmap, context->background_index);
+#endif
+        
+       return 0;
+}
+
+static void
+gif_set_get_frame_info (GifContext *context)
+{
+       context->state = GIF_GET_FRAME_INFO;
+}
+
+static gint
+gif_get_frame_info (GifContext *context)
+{
+       unsigned char buf[9];
+        
+       if (!gif_read (context, buf, 9)) {
+               return -1;
+       }
+        
+       /* Okay, we got all the info we need.  Lets record it */
+       context->frame_len = LM_to_uint (buf[4], buf[5]);
+       context->frame_height = LM_to_uint (buf[6], buf[7]);
+       context->x_offset = LM_to_uint (buf[0], buf[1]);
+       context->y_offset = LM_to_uint (buf[2], buf[3]);
+
+       if (context->animation->frames == NULL &&
+            context->gif89.disposal == 3) {
+                /* First frame can't have "revert to previous" as its
+                 * dispose mode. Silently use "retain" instead.
+                 */
+                context->gif89.disposal = 0;
+       }
+
+       context->frame_interlace = BitSet (buf[8], INTERLACE);
+
+#ifdef DUMP_IMAGE_DETAILS
+        g_print (">width: %d height: %d xoffset: %d yoffset: %d disposal: %d delay: %d transparent: %d interlace: %d\n",
+                 context->frame_len, context->frame_height, context->x_offset, context->y_offset,
+                 context->gif89.disposal, context->gif89.delay_time, context->gif89.transparent, context->frame_interlace);
+#endif
+        
+       if (BitSet (buf[8], LOCALCOLORMAP)) {
+
+#ifdef DUMP_IMAGE_DETAILS
+                g_print (">has local colormap\n");
+#endif
+                
+               /* Does this frame have it's own colormap. */
+               /* really only relevant when looking at the first frame
+                * of an animated gif. */
+               /* if it does, we need to re-read in the colormap,
+                * the gray_scale, and the bit_pixel */
+                context->frame_cmap_active = TRUE;
+               context->frame_bit_pixel = 1 << ((buf[8] & 0x07) + 1);
+               gif_set_get_colormap2 (context);
+               return 0;
+       }
+
+        if (!context->has_global_cmap) {
+                context->state = GIF_DONE;
+                
+                g_set_error_literal (context->error,
+                                     GDK_PIXBUF_ERROR,
+                                     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                                     _("GIF image has no global colormap, and a frame inside it has no local colormap."));
+                
+               return -2;
+        }
+
+       gif_set_prepare_lzw (context);
+       return 0;
+
+}
+
+static gint
+gif_get_next_step (GifContext *context)
+{
+       unsigned char c;
+       while (TRUE) {
+               if (!gif_read (context, &c, 1)) {
+                       return -1;
+               }
+               if (c == ';') {
+                       /* GIF terminator */
+                       /* hmm.  Not 100% sure what to do about this.  Should
+                        * i try to return a blank image instead? */
+                       context->state = GIF_DONE;
+                       return 0;
+               }
+
+               if (c == '!') {
+                       /* Check the extension */
+                       gif_set_get_extension (context);
+                       return 0;
+               }
+
+               /* look for frame */
+               if (c != ',') {
+                       /* Not a valid start character */
+                       continue;
+               }
+               /* load the frame */
+               gif_set_get_frame_info (context);
+               return 0;
+       }
+}
+
+
+#define LOG(x) /* g_print ("%s: %s\n", G_STRLOC, x); */
+
+static gint
+gif_main_loop (GifContext *context)
+{
+       gint retval = 0;
+
+       do {
+               switch (context->state) {
+               case GIF_START:
+                        LOG("start\n");
+                       retval = gif_init (context);
+                       break;
+
+               case GIF_GET_COLORMAP:
+                        LOG("get_colormap\n");
+                       retval = gif_get_colormap (context);
+                       if (retval == 0)
+                               context->state = GIF_GET_NEXT_STEP;
+                       break;
+
+               case GIF_GET_NEXT_STEP:
+                        LOG("next_step\n");
+                       retval = gif_get_next_step (context);
+                       break;
+
+               case GIF_GET_FRAME_INFO:
+                        LOG("frame_info\n");
+                       retval = gif_get_frame_info (context);
+                       break;
+
+               case GIF_GET_EXTENSION:
+                        LOG("get_extension\n");
+                       retval = gif_get_extension (context);
+                       if (retval == 0)
+                               context->state = GIF_GET_NEXT_STEP;
+                       break;
+
+               case GIF_GET_COLORMAP2:
+                        LOG("get_colormap2\n");
+                       retval = gif_get_colormap2 (context);
+                       if (retval == 0)
+                               gif_set_prepare_lzw (context);
+                       break;
+
+               case GIF_PREPARE_LZW:
+                        LOG("prepare_lzw\n");
+                       retval = gif_prepare_lzw (context);
+                       break;
+
+               case GIF_LZW_FILL_BUFFER:
+                        LOG("fill_buffer\n");
+                       retval = gif_lzw_fill_buffer (context);
+                       break;
+
+               case GIF_LZW_CLEAR_CODE:
+                        LOG("clear_code\n");
+                       retval = gif_lzw_clear_code (context);
+                       break;
+
+               case GIF_GET_LZW:
+                        LOG("get_lzw\n");
+                       retval = gif_get_lzw (context);
+                       break;
+
+               case GIF_DONE:
+                        LOG("done\n");
+               default:
+                       retval = 0;
+                       goto done;
+               };
+       } while ((retval == 0) || (retval == -3));
+ done:
+       return retval;
+}
+
+static GifContext *
+new_context (void)
+{
+       GifContext *context;
+
+       context = g_try_malloc (sizeof (GifContext));
+        if (context == NULL)
+                return NULL;
+
+        memset (context, 0, sizeof (GifContext));
+        
+        context->animation = g_object_new (GDK_TYPE_PIXBUF_GIF_ANIM, NULL);
+       context->frame = NULL;
+       context->file = NULL;
+       context->state = GIF_START;
+       context->prepare_func = NULL;
+       context->update_func = NULL;
+       context->user_data = NULL;
+       context->buf = NULL;
+       context->amount_needed = 0;
+       context->gif89.transparent = -1;
+       context->gif89.delay_time = -1;
+       context->gif89.input_flag = -1;
+       context->gif89.disposal = -1;
+        context->animation->loop = 1;
+        context->in_loop_extension = FALSE;
+        context->stop_after_first_frame = FALSE;
+
+       return context;
+}
 /* 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;
-
-    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);
-
-    /* Ok, now stuff the GdkPixBuf with goodies */
-
-    pixbuf = g_new(GdkPixBuf, 1);
-
-    if (is_trans)
-       pixbuf->art_pixbuf = art_pixbuf_new_rgba(pixels, w, h, (w * 4));
-    else
-       pixbuf->art_pixbuf = art_pixbuf_new_rgb(pixels, w, h, (w * 3));
-
-    /* Ok, I'm anal...shoot me */
-    if (!(pixbuf->art_pixbuf)) {
-        art_free(pixels);
-        g_free(pixbuf);
-       return NULL;
-    }
-
-    pixbuf->ref_count = 1;
-    pixbuf->unref_func = NULL;
-
-    return pixbuf;
-}
-
-image_save() {}
+static GdkPixbuf *
+gdk_pixbuf__gif_image_load (FILE *file, GError **error)
+{
+       GifContext *context;
+       GdkPixbuf *pixbuf;
+
+       g_return_val_if_fail (file != NULL, NULL);
+
+       context = new_context ();
+
+        if (context == NULL) {
+                g_set_error_literal (error,
+                                     GDK_PIXBUF_ERROR,
+                                     GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
+                                     _("Not enough memory to load GIF file"));
+                return NULL;
+        }
+        
+       context->file = file;
+        context->error = error;
+        context->stop_after_first_frame = TRUE;
+
+       if (gif_main_loop (context) == -1 || context->animation->frames == NULL) {
+                if (context->error && *(context->error) == NULL)
+                        g_set_error_literal (context->error,
+                                             GDK_PIXBUF_ERROR,
+                                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                                             _("GIF file was missing some data (perhaps it was truncated somehow?)"));
+        }
+        
+        pixbuf = gdk_pixbuf_animation_get_static_image (GDK_PIXBUF_ANIMATION (context->animation));
+
+        if (pixbuf)
+                g_object_ref (pixbuf);
+
+        g_object_unref (context->animation);
+        
+        g_free (context->buf);
+       g_free (context);
+       return pixbuf;
+}
+
+static gpointer
+gdk_pixbuf__gif_image_begin_load (GdkPixbufModuleSizeFunc size_func,
+                                  GdkPixbufModulePreparedFunc prepare_func,
+                                 GdkPixbufModuleUpdatedFunc update_func,
+                                 gpointer user_data,
+                                  GError **error)
+{
+       GifContext *context;
+
+#ifdef IO_GIFDEBUG
+       count = 0;
+#endif
+       context = new_context ();
+
+        if (context == NULL) {
+                g_set_error_literal (error,
+                                     GDK_PIXBUF_ERROR,
+                                     GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
+                                     _("Not enough memory to load GIF file"));
+                return NULL;
+        }
+        
+        context->error = error;
+       context->prepare_func = prepare_func;
+       context->update_func = update_func;
+       context->user_data = user_data;
+
+       return (gpointer) context;
+}
+
+static gboolean
+gdk_pixbuf__gif_image_stop_load (gpointer data, GError **error)
+{
+       GifContext *context = (GifContext *) data;
+        gboolean retval = TRUE;
+        
+        if (context->state != GIF_DONE || context->animation->frames == NULL) {
+                g_set_error_literal (error,
+                                     GDK_PIXBUF_ERROR,
+                                     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                                     _("GIF image was truncated or incomplete."));
+
+                retval = FALSE;
+        }
+        
+        g_object_unref (context->animation);
+
+       g_free (context->buf);
+       g_free (context);
+
+        return retval;
+}
+
+static gboolean
+gdk_pixbuf__gif_image_load_increment (gpointer data,
+                                      const guchar *buf, guint size,
+                                      GError **error)
+{
+       gint retval;
+       GifContext *context = (GifContext *) data;
+
+        context->error = error;
+        
+       if (context->amount_needed == 0) {
+               /* we aren't looking for some bytes. */
+               /* we can use buf now, but we don't want to keep it around at all.
+                * it will be gone by the end of the call. */
+               context->buf = (guchar*) buf; /* very dubious const cast */
+               context->ptr = 0;
+               context->size = size;
+       } else {
+               /* we need some bytes */
+               if (size < context->amount_needed) {
+                       context->amount_needed -= size;
+                       /* copy it over and return */
+                       memcpy (context->buf + context->size, buf, size);
+                       context->size += size;
+                       return TRUE;
+               } else if (size == context->amount_needed) {
+                       memcpy (context->buf + context->size, buf, size);
+                       context->size += size;
+               } else {
+                       context->buf = g_realloc (context->buf, context->size + size);
+                       memcpy (context->buf + context->size, buf, size);
+                       context->size += size;
+               }
+       }
+
+       retval = gif_main_loop (context);
+
+       if (retval == -2) {
+               if (context->buf == buf)
+                        context->buf = NULL;
+               return FALSE;
+        }
+       if (retval == -1) {
+               /* we didn't have enough memory */
+               /* prepare for the next image_load_increment */
+               if (context->buf == buf) {
+                       g_assert (context->size == size);
+                       context->buf = g_new (guchar, context->amount_needed + (context->size - context->ptr));
+                       memcpy (context->buf, buf + context->ptr, context->size - context->ptr);
+               } else {
+                       /* copy the left overs to the begining of the buffer */
+                       /* and realloc the memory */
+                       memmove (context->buf, context->buf + context->ptr, context->size - context->ptr);
+                       context->buf = g_realloc (context->buf, context->amount_needed + (context->size - context->ptr));
+               }
+               context->size = context->size - context->ptr;
+               context->ptr = 0;
+       } else {
+               /* we are prolly all done */
+               if (context->buf == buf)
+                       context->buf = NULL;
+       }
+       return TRUE;
+}
+
+static GdkPixbufAnimation *
+gdk_pixbuf__gif_image_load_animation (FILE *file,
+                                      GError **error)
+{
+       GifContext *context;
+       GdkPixbufAnimation *animation;
+
+       g_return_val_if_fail (file != NULL, NULL);
+
+       context = new_context ();
+
+        if (context == NULL) {
+                g_set_error_literal (error,
+                                     GDK_PIXBUF_ERROR,
+                                     GDK_PIXBUF_ERROR_INSUFFICIENT_MEMORY,
+                                     _("Not enough memory to load GIF file"));
+                return NULL;
+        }
+        
+        context->error = error;
+       context->file = file;
+
+       if (gif_main_loop (context) == -1 || context->animation->frames == NULL) {
+                if (context->error && *(context->error) == NULL)
+                        g_set_error_literal (context->error,
+                                             GDK_PIXBUF_ERROR,
+                                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                                             _("GIF file was missing some data (perhaps it was truncated somehow?)"));
+
+                g_object_unref (context->animation);
+                context->animation = NULL;
+        }
+
+        if (context->animation)
+                animation = GDK_PIXBUF_ANIMATION (context->animation);
+        else
+                animation = NULL;
+
+        if (context->error && *(context->error))
+                g_print ("%s\n", (*(context->error))->message);
+        
+        g_free (context->buf);
+       g_free (context);
+       return animation;
+}
+
+#ifndef INCLUDE_gif
+#define MODULE_ENTRY(function) G_MODULE_EXPORT void function
+#else
+#define MODULE_ENTRY(function) void _gdk_pixbuf__gif_ ## function
+#endif
+
+MODULE_ENTRY (fill_vtable) (GdkPixbufModule *module)
+{
+        module->load = gdk_pixbuf__gif_image_load;
+        module->begin_load = gdk_pixbuf__gif_image_begin_load;
+        module->stop_load = gdk_pixbuf__gif_image_stop_load;
+        module->load_increment = gdk_pixbuf__gif_image_load_increment;
+        module->load_animation = gdk_pixbuf__gif_image_load_animation;
+}
+
+MODULE_ENTRY (fill_info) (GdkPixbufFormat *info)
+{
+        static GdkPixbufModulePattern signature[] = {
+                { "GIF8", NULL, 100 },
+                { NULL, NULL, 0 }
+        };
+       static gchar * mime_types[] = {
+               "image/gif",
+               NULL
+       };
+       static gchar * extensions[] = {
+               "gif",
+               NULL
+       };
+
+       info->name = "gif";
+        info->signature = signature;
+       info->description = N_("The GIF image format");
+       info->mime_types = mime_types;
+       info->extensions = extensions;
+       info->flags = GDK_PIXBUF_FORMAT_THREADSAFE;
+       info->license = "LGPL";
+}