From 545b6c79703127e1a7490c7077592f8f65fd2b36 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Camilla=20L=C3=B6wy?= <elmindreda@glfw.org>
Date: Fri, 16 Jul 2021 20:04:56 +0200
Subject: [PATCH] Cocoa: Fix MoltenVK layer scale out of sync

The contents scale of the hosted CAMetalLayer created for MoltenVK was
updated only after the GLFW content scale and framebuffer size events
were emitted, causing the layer to get out of sync with the monitor the
window was on.

(cherry picked from commit 076bfd55be45e7ba5c887d4b32aa03d26881a1fb)
---
 README.md          |  2 ++
 src/cocoa_window.m | 25 ++++++++++++-------------
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/README.md b/README.md
index f1600a04..77897441 100644
--- a/README.md
+++ b/README.md
@@ -124,6 +124,8 @@ information on what to include when reporting a bug.
  - [Win32] Bugfix: `USE_MSVC_RUNTIME_LIBRARY_DLL` had no effect on CMake 3.15 or
    later (#1783,#1796)
  - [Win32] Bugfix: Compilation with LLVM for Windows failed (#1807,#1824,#1874)
+ - [Cocoa] Bugfix: The MoltenVK layer contents scale was updated only after
+   related events were emitted
  - [EGL] Bugfix: The `GLFW_DOUBLEBUFFER` context attribute was ignored (#1843)
 
 
diff --git a/src/cocoa_window.m b/src/cocoa_window.m
index 32a55512..6f442134 100644
--- a/src/cocoa_window.m
+++ b/src/cocoa_window.m
@@ -520,6 +520,18 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
 {
     const NSRect contentRect = [window->ns.view frame];
     const NSRect fbRect = [window->ns.view convertRectToBacking:contentRect];
+    const float xscale = fbRect.size.width / contentRect.size.width;
+    const float yscale = fbRect.size.height / contentRect.size.height;
+
+    if (xscale != window->ns.xscale || yscale != window->ns.yscale)
+    {
+        if (window->ns.retina && window->ns.layer)
+            [window->ns.layer setContentsScale:[window->ns.object backingScaleFactor]];
+
+        window->ns.xscale = xscale;
+        window->ns.yscale = yscale;
+        _glfwInputWindowContentScale(window, xscale, yscale);
+    }
 
     if (fbRect.size.width != window->ns.fbWidth ||
         fbRect.size.height != window->ns.fbHeight)
@@ -528,19 +540,6 @@ static const NSRange kEmptyRange = { NSNotFound, 0 };
         window->ns.fbHeight = fbRect.size.height;
         _glfwInputFramebufferSize(window, fbRect.size.width, fbRect.size.height);
     }
-
-    const float xscale = fbRect.size.width / contentRect.size.width;
-    const float yscale = fbRect.size.height / contentRect.size.height;
-
-    if (xscale != window->ns.xscale || yscale != window->ns.yscale)
-    {
-        window->ns.xscale = xscale;
-        window->ns.yscale = yscale;
-        _glfwInputWindowContentScale(window, xscale, yscale);
-
-        if (window->ns.retina && window->ns.layer)
-            [window->ns.layer setContentsScale:[window->ns.object backingScaleFactor]];
-    }
 }
 
 - (void)drawRect:(NSRect)rect