The configuration tool for compton is a part of the LXQt desktop environment, but it's missing from the Gentoo repositories. The attatched ebuild works in my regular Gentoo install but hasn't been tested in a proper test environment and it may not be written according to the ebuild guidelines; it is only meant as a helpful suggestion, not an ebuild submission. Reproducible: Always
Created attachment 597648 [details] compton-conf-0.14.1.ebuild
Development for compton has stopped, and it was removed from the tree today with https://sources.gentoo.org/repo/gentoo.git/commit/?id=ed815fef0f75faf3cba4e98530a42423a9989483