feature req: switch to graphicsmagick for processing

Can you backup the claim with some benchmarks, specifically for the commands Variety uses (e.g. clock and the default filters), on different images (both full hd and 4k)?

Basically, unless there is a substantial difference I would consider this a bad move - ImageMagick is older, way more popular, pretty well documented, and much more probable to already be installed on a user's machine when they install Variety. And I am not sure we don't rely on some newer features of ImageMagick (post version 6).

Since Variety has to run the image-processing on a fairly large interval (e.g. the clock being drawn every minute is the most often-used imagemagick operation for most users), a drop in processing time, say, from 1 to 0.6 seconds seems fairly minor.

In testing here, it looks like you're right, there isn't a substantial enough difference between the 2 to make this worthwhile. I'm having weird issues where changing wallpaper using variety (16.04b) can take up to 20s, I assumed it was in the image conversion step, but that doesn't seem to be the case, so I'm not certain what's causing it now. Maybe just the setting step in unity.

If you're using Debian or Ubuntu, another option is to install graphicsmagick-imagemagick-compat from APT: it provides an imagemagick command but actually uses the GraphicsMagick library. http://packages.ubuntu.com/yakkety/imagemagick