Adds a gradient dithering function to pixman.
As presented in https://lists.freedesktop.org/archives/pixman/2018-April/004714.html
Corresponds to bug #25 (closed)
Edited by Marc Jeanmougin
As presented in https://lists.freedesktop.org/archives/pixman/2018-April/004714.html
Corresponds to bug #25 (closed)