From 8230df39a500e1db62fdd68d2b1e767120747c39 Mon Sep 17 00:00:00 2001
From: Le Hoang Quyen <lehoangq@gmail.com>
Date: Sat, 17 Oct 2020 13:51:01 +0800
Subject: [PATCH] #34: Auto detect CALayer's contentsScale change.

---
 src/libANGLE/renderer/metal/SurfaceMtl.mm | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/libANGLE/renderer/metal/SurfaceMtl.mm b/src/libANGLE/renderer/metal/SurfaceMtl.mm
index 7d25537f6d..6a850359ad 100644
--- a/src/libANGLE/renderer/metal/SurfaceMtl.mm
+++ b/src/libANGLE/renderer/metal/SurfaceMtl.mm
@@ -579,6 +579,12 @@ void StopFrameCapture()
 
 bool SurfaceMtl::checkIfLayerResized(const gl::Context *context)
 {
+    if (mMetalLayer.get() != mLayer && mMetalLayer.get().contentsScale != mLayer.contentsScale)
+    {
+        // Parent layer's content scale has changed, update Metal layer's scale factor.
+        mMetalLayer.get().contentsScale = mLayer.contentsScale;
+    }
+
     CGSize currentLayerDrawableSize = mMetalLayer.get().drawableSize;
     CGSize expectedDrawableSize     = calcExpectedDrawableSize();