Open Radar

 
Area:
UIKit

Summary:

The method:
[view drawViewHierarchyInRect:frame afterScreenUpdates:NO];

performs poorly on the iPhone X with iOS 12. This is a regression since we did not observe this issue with iOS 11.

Steps to Reproduce:

Call the method:
[view drawViewHierarchyInRect:frame afterScreenUpdates:NO];

to render every frame (15 FPS)



Expected Results:

Performance of the drawViewHierarchyInRect should not be worse in iOS 12 than in iOS 11 on the iPhone X.


Actual Results:

For the same sized view 800 x 480 the method
[view drawViewHierarchyInRect:frame afterScreenUpdates:NO]
takes 300ms longer on the iPhone X than the iPhone 6s+

iPhone X with iOS 12:
2018-10-12 14:19:47.332431+0200 TomTom[2119:460864] size = {800, 480}, time1 = 0 ms, time2 = 0 ms, time3 = 371 ms, time4 = 371 ms
2018-10-12 14:19:47.691679+0200 TomTom[2119:460864] size = {800, 480}, time1 = 0 ms, time2 = 0 ms, time3 = 357 ms, time4 = 357 ms
2018-10-12 14:19:48.052285+0200 TomTom[2119:460864] size = {800, 480}, time1 = 0 ms, time2 = 1 ms, time3 = 360 ms, time4 = 360 ms

iPhone 6s+ with iOS 12:
2018-10-12 13:25:36.165425+0200 TomTom[1250:434003] size = {800, 480}, time1 = 0 ms, time2 = 0 ms, time3 = 62 ms, time4 = 62 ms
2018-10-12 13:25:36.230865+0200 TomTom[1250:434003] size = {800, 480}, time1 = 0 ms, time2 = 1 ms, time3 = 64 ms, time4 = 64 ms
2018-10-12 13:25:36.294131+0200 TomTom[1250:434003] size = {800, 480}, time1 = 0 ms, time2 = 1 ms, time3 = 62 ms, time4 = 62 ms


Version/Build:

iOS 12.0 (16A366)
iOS 12.1

Configuration:

iPhone X with iOS 12.0
iPhone X with iOS 12.1
iPhone 7 with iOS 12.1