ImageMagick: How can I cut out round from image?

Question

I'm trying to make a round avatar out of some image. How can I cut out round from image using ImageMagick?

Answer 1

There are various ways, but the simplest is probably the undocumented "-vignette" option:

magick CLg93.jpg -vignette 1x1 kim_vignette.jpg

yields

You can deal with non-square images by applying an "offset" to the vignette geometry, for example:

-vignette 1x1+0+50

if the input image is a portrait that is 100 pixels taller than it is wide.