
For animating the arrows on the screenshield, we currently use a custom transition function that tweens the opacity from 0 to maxOpacity in the first half of the animation, and from maxOpacity back to 0 in the second half. This doesn't easily translate to Clutter's own animation framework, so replace the custom transition with two consecutive tweens which do. https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/22