Support the Netscape application extension for gif animations (#95060):

gdk-pixbuf/ChangeLog

+2002-10-21  Matthias Clasen  <maclas@gmx.de>
+
+	Support the Netscape application extension for gif animations 
+	(#95060):
+	
+	* io-gif-animation.h: 
+	* io-gif-animation.c (gdk_pixbuf_gif_anim_iter_advance): 
+	Add loop count to GdkPixbufGifAnim and use it in the advance
+	method of GdkPixbufGifAnimIter.
+	
+	* io-gif.c (gif_get_extension): Parse Netscape application
+	extension block and set the animation loop count. 
+
 2002-10-11  Matthias Clasen  <maclas@gmx.de>
 
 	* gdk-pixbuf-loader.c (gdk_pixbuf_loader_get_format): Remove

gdk-pixbuf/io-gif-animation.c

@@ -260,6 +260,7 @@ gdk_pixbuf_gif_anim_iter_advance (GdkPixbufAnimationIter *anim_iter,
 {
         GdkPixbufGifAnimIter *iter;
         gint elapsed;
+        gint loop;
         GList *tmp;
         GList *old;
         
@@ -285,12 +286,17 @@ gdk_pixbuf_gif_anim_iter_advance (GdkPixbufAnimationIter *anim_iter,
         /* See how many times we've already played the full animation,
          * and subtract time for that.
          */
+
+        loop = elapsed / iter->gif_anim->total_time;
         elapsed = elapsed % iter->gif_anim->total_time;
 
         iter->position = elapsed;
-        
+
         /* Now move to the proper frame */
-        tmp = iter->gif_anim->frames;
+        if (iter->gif_anim->loop == 0 || loop < iter->gif_anim->loop) 
+                tmp = iter->gif_anim->frames;
+        else 
+                tmp = NULL;
         while (tmp != NULL) {
                 GdkPixbufFrame *frame = tmp->data;
                 
@@ -525,7 +531,7 @@ gdk_pixbuf_gif_anim_iter_get_pixbuf (GdkPixbufAnimationIter *anim_iter)
         
         iter = GDK_PIXBUF_GIF_ANIM_ITER (anim_iter);
 
-        frame = iter->current_frame ? iter->current_frame->data : NULL;
+        frame = iter->current_frame ? iter->current_frame->data : g_list_last (iter->gif_anim->frames)->data;
 
 #if 0
         if (FALSE && frame)

gdk-pixbuf/io-gif-animation.h

@@ -76,6 +76,8 @@ struct _GdkPixbufGifAnim {
         guchar bg_red;
         guchar bg_green;
         guchar bg_blue;
+        
+        int loop;
 };
 
 struct _GdkPixbufGifAnimClass {

gdk-pixbuf/io-gif.c

@@ -83,7 +83,7 @@ enum {
 	GIF_GET_COLORMAP,
 	GIF_GET_NEXT_STEP,
 	GIF_GET_FRAME_INFO,
-	GIF_GET_EXTENTION,
+	GIF_GET_EXTENSION,
 	GIF_GET_COLORMAP2,
 	GIF_PREPARE_LZW,
 	GIF_LZW_FILL_BUFFER,
@@ -149,6 +149,7 @@ struct _GifContext
 	/* extension context */
 	guchar extension_label;
 	guchar extension_flag;
+        gboolean in_loop_extension;
 
 	/* get block context */
 	guchar block_count;
@@ -353,7 +354,7 @@ get_data_block (GifContext *context,
 static void
 gif_set_get_extension (GifContext *context)
 {
-	context->state = GIF_GET_EXTENTION;
+	context->state = GIF_GET_EXTENSION;
 	context->extension_flag = TRUE;
 	context->extension_label = 0;
 	context->block_count = 0;
@@ -376,8 +377,8 @@ gif_get_extension (GifContext *context)
 		}
 
 		switch (context->extension_label) {
-		case 0xf9:			/* Graphic Control Extension */
-			retval = get_data_block (context, (unsigned char *) context->block_buf, NULL);
+                case 0xf9:			/* Graphic Control Extension */
+                        retval = get_data_block (context, (unsigned char *) context->block_buf, NULL);
 			if (retval != 0)
 				return retval;
 
@@ -399,6 +400,36 @@ gif_get_extension (GifContext *context)
 			/* 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 (context->block_buf, "NETSCAPE2.0", 11) ||
+                                    !strncmp (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;
@@ -1280,7 +1311,7 @@ gif_main_loop (GifContext *context)
 			retval = gif_get_frame_info (context);
 			break;
 
-		case GIF_GET_EXTENTION:
+		case GIF_GET_EXTENSION:
                         LOG("get_extension\n");
 			retval = gif_get_extension (context);
 			if (retval == 0)
@@ -1349,6 +1380,8 @@ new_context (void)
 	context->gif89.delay_time = -1;
 	context->gif89.input_flag = -1;
 	context->gif89.disposal = -1;
+        context->animation->loop = 1;
+        context->in_loop_extension = FALSE;
 
 	return context;
 }