; * src/w32image.c (w32_select_active_frame): Comment about GUID values.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/w32image.c b/src/w32image.c
index 80c3247e97d..0a2a55d3f6f 100644
--- a/src/w32image.c
+++ b/src/w32image.c
@@ -283,6 +283,11 @@ w32_select_active_frame (GpBitmap *pBitmap, int frame, int *nframes,
   *delay = 0.0;
   if (count)
     {
+      /* The following call will fill pDimensionIDs[0] with the
+         FrameDimensionTime GUID for GIF images, and
+         FrameDimensionPage GUID for other image types.  Multi-page
+         GIF and TIFF images expect these values in the
+         GdipImageSelectActiveFrame call below.  */
       status = GdipImageGetFrameDimensionsList (pBitmap, pDimensionIDs, 1);
       status = GdipImageGetFrameCount (pBitmap, &pDimensionIDs[0], &frameCount);
       if (status == Ok && frameCount > 1)