CALayer bounds updated ahead of NSWindow frame when rendered to from separate thread

Originator:torarnv
Number:rdar://41517629 Date Originated:June 27 2018
Status:Open Resolved:
Product:macOS + SDK Product Version:10.13
Classification:Bug Reproducible:Always
 
Area:
Core Graphics

Summary:

When enabling layer-backed mode for a NSOpenGLView, and rendering to it from a separate thread, eg. a display-link callback, you may end up in a situation where during window resize the CALayer bounds seem to be updated ahead of the NSWindow frame:

https://www.youtube.com/watch?v=vqwgtxCqvx4

Steps to Reproduce:

1. Download https://developer.apple.com/library/archive/samplecode/GLEssentials
2. Add to awakeFromNib:

    self.wantsLayer = YES;
    self.layer.borderColor = [NSColor cyanColor].CGColor;
    self.layer.borderWidth = 1;

Expected Results:

Resizing the window behaves the same as with non-layer-backed mode; the layer follows the window frame.

Actual Results:

The layer bounds are updated ahead of the window frame.

Version/Build:

macOS 10.13.4

Comments

Minimal testcase

https://gist.github.com/torarnv/077591297538a955bd24500102eac834


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