macOS: Don't update Metal layer's drawableSize automatically

Like our other rendering code paths, the Metal path should allow the user
to resize their surface when they see fit. This is the case today with
e.g QBackingStore::resize() and QOpenGLPaintDevice::setSize().

[ChangeLog][macOS] The drawableSize of Metal layers is no longer updated
automatically on window resize or screen change. Update the size manually
in response to resizeEvent(), or at the start of each frame, as needed.

Change-Id: I9ed6d4326d0e0a3f4e3c63984d3b193e8bb77cae
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

1 files changed, 2 insertions, 21 deletions

diff --git a/src/plugins/platforms/cocoa/qnsview_drawing.mm b/src/plugins/platforms/cocoa/qnsview_drawing.mm
index de93e03685..e72142466b 100644
--- a/src/plugins/platforms/cocoa/qnsview_drawing.mm
+++ b/src/plugins/platforms/cocoa/qnsview_drawing.mm
@@ -173,20 +173,6 @@
 }
 #endif
 
-- (void)updateMetalLayerDrawableSize:(CAMetalLayer *)layer
-{
-    CGSize drawableSize = layer.bounds.size;
-    drawableSize.width *= layer.contentsScale;
-    drawableSize.height *= layer.contentsScale;
-    layer.drawableSize = drawableSize;
-}
-
-- (void)layoutSublayersOfLayer:(CALayer *)layer
-{
-    if ([layer isKindOfClass:CAMetalLayer.class])
-        [self updateMetalLayerDrawableSize:static_cast<CAMetalLayer* >(layer)];
-}
-
 - (void)displayLayer:(CALayer *)layer
 {
     if (!NSThread.isMainThread) {
@@ -213,13 +199,8 @@
 {
     qCDebug(lcQpaDrawing) << "Backing properties changed for" << self;
 
-    if (CALayer *layer = self.layer) {
-        layer.contentsScale = self.window.backingScaleFactor;
-
-        // Metal layers must be manually updated on e.g. screen change
-        if ([layer isKindOfClass:CAMetalLayer.class])
-            [self updateMetalLayerDrawableSize:static_cast<CAMetalLayer* >(layer)];
-    }
+    if (self.layer)
+        self.layer.contentsScale = self.window.backingScaleFactor;
 
     // Ideally we would plumb this situation through QPA in a way that lets
     // clients invalidate their own caches, recreate QBackingStore, etc.