ImageMagick convert gif with transparency problem

Question

I wrote a script to add watermark to images on my site. Everything works ok for png/jpg, but gif images must be treaten by more complicated way. My script:

convert -splice x36 -gravity south -background white image.gif \
-coalesce -gravity SouthEast -geometry +0+0 -background white \
null: watermark-text.png -layers composite new-image.gif

For 95 percent of gif it works fine. But there are some examples, that brings errors. Concern this image:

Normal cat. Only first frame contains background (viewed layers in gimp).

This is not normal cat. Any suggestions?

Answer 1

The problem is that your -splice is being applied relative to the gif's frames' layout rather than the complete image's layout. Do the -coalesce first (order matters):

convert -coalesce -splice x36 -gravity south -background white image.gif \
-gravity SouthEast -geometry +0+0 -background white \
null: watermark-text.png -layers composite new-image.gif

See "Simple Modifications of Animations" from the Examples of ImageMagick Usage for more information.