Fade out whole icons instead of using StScrollViewFade (rotating design)
By avoiding StScrollViewFade we avoid offscreening and therefore
avoid painting everything twice to get it on screen. So this almost
halves the render time of the icon grid.
Scrolling performance at 4K on a basic Intel HD 630 GPU:
| Render times | Average | Peak |
|---|---|---|
| Before | 20 ms | 23 ms |
| After | 12 ms | 14 ms |
Related: #4367 (closed), !1884 (closed), #174 (closed)
Edited by Daniel van Vugt