Reset block_count to 0 for all application extensions, otherwise the data

2003-06-22  Matthias Clasen  <matthias@localhost.localdomain>

	* io-gif.c (gif_get_extension): Reset block_count to 0 for all application extensions, otherwise the data blocks
	of unknown extensions are not propertly skipped.

	Second half of the fix for #106962, handle frames extending beyond the logical screen:

	* io-gif.c (clip_frame): New helper function to clip a rectangle to the logical screen size of the gif.
	(maybe_update): New helper function to call update_func only if the rectangle is not completely off-bounds.
	(gif_get_lzw): Read frames extending outside the logical screen size, but be careful clip to the logical screen size
	when operating on the composite pixbuf and when calling update_func.
	(gif_init): Set the animation size to the logical screen size.
	(gif_get_frame_info): Don't refuse to load images with frames extending beyond the logical screen size.

	* io-gif-animation.c (gdk_pixbuf_gif_anim_frame_composite): Be careful to clip all rectangles to the logical screen
	size, also handle the fact that frames may be completely off-bounds.

1 files changed, 71 insertions, 70 deletions

diff --git a/gdk-pixbuf/io-gif-animation.c b/gdk-pixbuf/io-gif-animation.c
index 97062ba9c..bf50a9363 100644
--- a/gdk-pixbuf/io-gif-animation.c
+++ b/gdk-pixbuf/io-gif-animation.c
@@ -391,7 +391,9 @@ gdk_pixbuf_gif_anim_frame_composite (GdkPixbufGifAnim *gif_anim,
                 
                 while (tmp != NULL) {
                         GdkPixbufFrame *f = tmp->data;
-
+                        gint clipped_width = MIN (gif_anim->width - f->x_offset, gdk_pixbuf_get_width (f->pixbuf));
+                        gint clipped_height = MIN (gif_anim->height - f->y_offset, gdk_pixbuf_get_height (f->pixbuf));
+  
                         if (f->need_recomposite) {
                                 if (f->composited) {
                                         g_object_unref (f->composited);
@@ -419,26 +421,17 @@ gdk_pixbuf_gif_anim_frame_composite (GdkPixbufGifAnim *gif_anim,
                                                  (gif_anim->bg_green << 16) |
                                                  (gif_anim->bg_blue << 8));
 
-                                gdk_pixbuf_composite (f->pixbuf,
-                                                      f->composited,
-                                                      f->x_offset,
-                                                      f->y_offset,
-                                                      gdk_pixbuf_get_width (f->pixbuf),
-                                                      gdk_pixbuf_get_height (f->pixbuf),
-                                                      f->x_offset, f->y_offset,
-                                                      1.0, 1.0,
-                                                      GDK_INTERP_BILINEAR,
-                                                      255);
-#if 0                                
-                                gdk_pixbuf_copy_area (f->pixbuf,
-                                                      0, 0,
-                                                      gdk_pixbuf_get_width (f->pixbuf),
-                                                      gdk_pixbuf_get_height (f->pixbuf),
-                                                      f->composited,
-                                                      f->x_offset,
-                                                      f->y_offset);
-                                
-#endif
+                                if (clipped_width > 0 && clipped_height > 0)
+                                        gdk_pixbuf_composite (f->pixbuf,
+                                                              f->composited,
+                                                              f->x_offset,
+                                                              f->y_offset,
+                                                              clipped_width,
+                                                              clipped_height,
+                                                              f->x_offset, f->y_offset,
+                                                              1.0, 1.0,
+                                                              GDK_INTERP_BILINEAR,
+                                                              255);
                                 
                                 if (f->action == GDK_PIXBUF_FRAME_REVERT)
                                         g_warning ("First frame of GIF has bad dispose mode, GIF loader should not have loaded this image");
@@ -449,6 +442,9 @@ gdk_pixbuf_gif_anim_frame_composite (GdkPixbufGifAnim *gif_anim,
                                 
                                 prev_frame = tmp->prev->data;
 
+                                gint prev_clipped_width = MIN (gif_anim->width - prev_frame->x_offset, gdk_pixbuf_get_width (prev_frame->pixbuf));
+                                gint prev_clipped_height = MIN (gif_anim->height - prev_frame->y_offset, gdk_pixbuf_get_height (prev_frame->pixbuf));
+
                                 /* Init f->composited with what we should have after the previous
                                  * frame
                                  */
@@ -457,66 +453,71 @@ gdk_pixbuf_gif_anim_frame_composite (GdkPixbufGifAnim *gif_anim,
                                         f->composited = gdk_pixbuf_copy (prev_frame->composited);
                                         
                                 } else if (prev_frame->action == GDK_PIXBUF_FRAME_DISPOSE) {
-                                        GdkPixbuf *area;
-                                        
                                         f->composited = gdk_pixbuf_copy (prev_frame->composited);
-
-                                        /* Clear area of previous frame to background */
-                                        area = gdk_pixbuf_new_subpixbuf (f->composited,
-                                                                         prev_frame->x_offset,
-                                                                         prev_frame->y_offset,
-                                                                         gdk_pixbuf_get_width (prev_frame->pixbuf),
-                                                                         gdk_pixbuf_get_height (prev_frame->pixbuf));
-
-                                        gdk_pixbuf_fill (area,
-                                                         (gif_anim->bg_red << 24) |
-                                                         (gif_anim->bg_green << 16) |
-                                                         (gif_anim->bg_blue << 8));
-
-                                        g_object_unref (area);
-                                        
+                                        if (prev_clipped_width > 0 && prev_clipped_height > 0) {
+                                                /* Clear area of previous frame to background */
+                                                GdkPixbuf *area;
+
+                                                area = gdk_pixbuf_new_subpixbuf (f->composited,
+                                                                                 prev_frame->x_offset,
+                                                                                 prev_frame->y_offset,
+                                                                                 prev_clipped_width,
+                                                                                 prev_clipped_height);
+                                                
+                                                gdk_pixbuf_fill (area,
+                                                                 (gif_anim->bg_red << 24) |
+                                                                 (gif_anim->bg_green << 16) |
+                                                                 (gif_anim->bg_blue << 8));
+                                                
+                                                g_object_unref (area);
+                                        }                                        
                                 } else if (prev_frame->action == GDK_PIXBUF_FRAME_REVERT) {
                                         f->composited = gdk_pixbuf_copy (prev_frame->composited);
-
-                                        /* Copy in the revert frame */
-                                        gdk_pixbuf_copy_area (prev_frame->revert,
-                                                              0, 0,
-                                                              gdk_pixbuf_get_width (prev_frame->revert),
-                                                              gdk_pixbuf_get_height (prev_frame->revert),
-                                                              f->composited,
-                                                              prev_frame->x_offset,
-                                                              prev_frame->y_offset);
+                                        if (prev_clipped_width > 0 && prev_clipped_height > 0) {
+                                                /* Copy in the revert frame */
+                                                gdk_pixbuf_copy_area (prev_frame->revert,
+                                                                      0, 0,
+                                                                      gdk_pixbuf_get_width (prev_frame->revert),
+                                                                      gdk_pixbuf_get_height (prev_frame->revert),
+                                                                      f->composited,
+                                                                      prev_frame->x_offset,
+                                                                      prev_frame->y_offset);
+                                        }
                                 } else {
                                         g_warning ("Unknown revert action for GIF frame");
                                 }
 
                                 if (f->revert == NULL &&
                                     f->action == GDK_PIXBUF_FRAME_REVERT) {
-                                        /* We need to save the contents before compositing */
-                                        GdkPixbuf *area;
-
-                                        area = gdk_pixbuf_new_subpixbuf (f->composited,
-                                                                         f->x_offset,
-                                                                         f->y_offset,
-                                                                         gdk_pixbuf_get_width (f->pixbuf),
-                                                                         gdk_pixbuf_get_height (f->pixbuf));
-
-                                        f->revert = gdk_pixbuf_copy (area);
-                                        
-                                        g_object_unref (area);
+                                        if (clipped_width > 0 && clipped_height > 0) {
+                                                /* We need to save the contents before compositing */
+                                                GdkPixbuf *area;
+                                                
+                                                area = gdk_pixbuf_new_subpixbuf (f->composited,
+                                                                                 f->x_offset,
+                                                                                 f->y_offset,
+                                                                                 clipped_width,
+                                                                                 clipped_height);
+                                                
+                                                f->revert = gdk_pixbuf_copy (area);
+                                                
+                                                g_object_unref (area);
+                                        }
                                 }
 
-                                /* Put current frame onto f->composited */
-                                gdk_pixbuf_composite (f->pixbuf,
-                                                      f->composited,
-                                                      f->x_offset,
-                                                      f->y_offset,
-                                                      gdk_pixbuf_get_width (f->pixbuf),
-                                                      gdk_pixbuf_get_height (f->pixbuf),
-                                                      f->x_offset, f->y_offset,
-                                                      1.0, 1.0,
-                                                      GDK_INTERP_NEAREST,
-                                                      255);
+                                if (clipped_width > 0 && clipped_height > 0) {
+                                        /* Put current frame onto f->composited */
+                                        gdk_pixbuf_composite (f->pixbuf,
+                                                              f->composited,
+                                                              f->x_offset,
+                                                              f->y_offset,
+                                                              clipped_width,
+                                                              clipped_height,
+                                                              f->x_offset, f->y_offset,
+                                                              1.0, 1.0,
+                                                              GDK_INTERP_NEAREST,
+                                                              255);
+                                }
                         
                                 f->need_recomposite = FALSE;
                         }