Crop for animated images

[Mefgalm]

Hello! Thanks for this great library!

I have .gif and .webp files, on which I try to apply Image.thumbnail(image, dims, crop: center) which leads to the animation disappearing. When opening images I pass pages: -1. Resizing animated images works correctly.

Perhaps libvips itself does not currently support this option: libvips/libvips#2668

[kipcole9]

I believe you are correct in that libvips doesn't support thumbnailing/cropping animated images.

I think I might be able to do this for webp simple animated images (ones that don't have the ANIM chunk and just have simple loop and delay headers) by splitting the image, cropping each frame and reassembling.

I'll do some experiments today on this. If webp works well enough I'll take a look at gif.