(imagemagick_compute_animated_image): Allow certain degenerate images

(imagemagick_compute_animated_image): Allow images that say they
have sub-images that are bigger than the main image, but just crop
them.

2 files changed, 15 insertions, 13 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 431802eab45..dd4697298ac 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -4,6 +4,9 @@
         when sub-images are smaller than the main image.
         (imagemagick_compute_animated_image): Setting the iterator row to
         zero is apparently not allowed.
+        (imagemagick_compute_animated_image): Allow images that say they
+        have sub-images that are bigger than the main image, but just crop
+        them.
 
 2013-08-15  Jan Djärv  <jan.h.d@swipnet.se>
 
diff --git a/src/image.c b/src/image.c
index 6f92c583554..d7e1d7991dd 100644
--- a/src/image.c
+++ b/src/image.c
@@ -7900,6 +7900,7 @@ imagemagick_compute_animated_image (MagickWand *super_wand, int ino)
       ssize_t source_left, source_top;
       MagickPixelPacket pixel;
       DisposeType dispose;
+      ptrdiff_t lines = 0;
 
       MagickSetIteratorIndex (super_wand, i);
       sub_wand = MagickGetImage (super_wand);
@@ -7907,17 +7908,6 @@ imagemagick_compute_animated_image (MagickWand *super_wand, int ino)
       MagickGetImagePage (sub_wand, &source_width, &source_height,
                           &source_left, &source_top);
 
-      /* Sanity check.  The sub-image should not be bigger than the
-         base image.  */
-      if (source_height + source_top > dest_height)
-        {
-          DestroyMagickWand (composite_wand);
-          DestroyMagickWand (sub_wand);
-          animation_cache = NULL;
-          image_error ("Inconsinstent animation size", Qnil, Qnil);
-          return NULL;
-        }
-
       dispose = MagickGetImageDispose (sub_wand);
 
       source_iterator = NewPixelIterator (sub_wand);
@@ -7946,17 +7936,26 @@ imagemagick_compute_animated_image (MagickWand *super_wand, int ino)
       /* The sub-image may not start at origo, so move the destination
          iterator to where the sub-image should start. */
       if (source_top > 0)
-        PixelSetIteratorRow (dest_iterator, source_top);
+        {
+          PixelSetIteratorRow (dest_iterator, source_top);
+          lines = source_top;
+        }
 
       while ((source = PixelGetNextIteratorRow (source_iterator, &source_width))
              != NULL)
         {
           ptrdiff_t x;
+
+          /* Sanity check.  This shouldn't happen, but apparently
+             does in some pictures.  */
+          if (++lines >= dest_height)
+            break;
+
           dest = PixelGetNextIteratorRow (dest_iterator, &dest_width);
           for (x = 0; x < source_width; x++)
             {
               /* Sanity check.  This shouldn't happen, but apparently
-                 does in some pictures.  */
+                 also does in some pictures.  */
               if (x + source_left > dest_width)
                 break;
               /* Normally we only copy over non-transparent pixels,