--- tools/sk_app/mac/WindowContextFactory_mac.h	2022-02-16 06:03:39.000000000 -0500
+++ tools/sk_app/mac/WindowContextFactory_mac.h	2023-01-25 08:09:00.000000000 -0500
@@ -19,15 +19,8 @@
 
 struct DisplayParams;
 
-static inline CGFloat GetBackingScaleFactor(NSView* view) {
-    #ifdef SK_BUILD_FOR_IOS
-    UIScreen* screen = view.window.screen ?: [UIScreen mainScreen];
-    return screen.nativeScale;
-    #else
-    NSScreen* screen = view.window.screen ?: [NSScreen mainScreen];
-    return screen.backingScaleFactor;
-    #endif
-}
+SK_API CGFloat GetBackingScaleFactor(NSView* view);
+SK_API void ResetBackingScaleFactor();
 
 namespace window_context_factory {
 
--- /dev/null	2023-01-25 09:20:55.000000000 -0500
+++ tools/sk_app/mac/WindowContextFactory_mac.mm	2023-01-25 09:21:22.000000000 -0500
@@ -0,0 +1,57 @@
+/*
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "tools/sk_app/mac/WindowContextFactory_mac.h"
+
+namespace sk_app {
+
+static bool  bWindowScaling = false;
+static float fWindowScale = 1.0f;
+
+CGFloat GetBackingScaleFactor(NSView* view) {
+    #ifdef SK_BUILD_FOR_IOS
+    UIScreen* screen = view.window.screen ?: [UIScreen mainScreen];
+    return screen.nativeScale;
+    #else
+    // Related: tdf#147342 This should always be an exact copy of the
+    // sal::aqua::getWindowScaling() function in the following file:
+    // vcl/osx/salgdiutils.cxx
+    (void)view;
+
+    if (!bWindowScaling)
+    {
+        NSArray *aScreens = [NSScreen screens];
+        if (aScreens)
+        {
+            for (NSScreen *aScreen : aScreens)
+            {
+                float fScale = [aScreen backingScaleFactor];
+                if (fScale > fWindowScale)
+                  fWindowScale = fScale;
+            }
+            bWindowScaling = true;
+        }
+        if( const char* env = getenv("SAL_FORCE_HIDPI_SCALING"))
+        {
+            fWindowScale = atof(env);
+            bWindowScaling = true;
+        }
+    }
+    return fWindowScale;
+    #endif
+}
+
+void ResetBackingScaleFactor() {
+    #ifndef SK_BUILD_FOR_IOS
+    // Related: tdf#147342 Force recalculation of the window scaling but keep
+    // the previous window scaling as the minimum so that we don't lose the
+    // resolution in cached images if a HiDPI monitor is disconnected and
+    // then reconnected.
+    bWindowScaling = false;
+    GetBackingScaleFactor(nil);
+    #endif
+}
+
+}  // namespace sk_app
--- tools/sk_app/mac/MetalWindowContext_mac.mm	2024-08-31 15:49:57
+++ tools/sk_app/mac/MetalWindowContext_mac.mm	2024-09-25 20:09:32
@@ -11,6 +11,8 @@
 #import <Cocoa/Cocoa.h>
 #import <QuartzCore/CAConstraintLayoutManager.h>
 
+#include <sal/log.hxx>
+
 using sk_app::DisplayParams;
 using sk_app::window_context_factory::MacWindowInfo;
 using sk_app::MetalWindowContext;
@@ -66,8 +68,7 @@
     fMetalLayer.autoresizingMask = kCALayerHeightSizable | kCALayerWidthSizable;
     fMetalLayer.contentsGravity = kCAGravityTopLeft;
     fMetalLayer.magnificationFilter = kCAFilterNearest;
-    NSColorSpace* cs = fMainView.window.colorSpace;
-    fMetalLayer.colorspace = cs.CGColorSpace;
+    fMetalLayer.colorspace = CGColorSpaceCreateWithName(kCGColorSpaceSRGB);
 
     fMainView.layer = fMetalLayer;
     fMainView.wantsLayer = YES;
@@ -86,6 +87,18 @@
     fMetalLayer.drawableSize = backingSize;
     fMetalLayer.contentsScale = backingScaleFactor;
 
+    // Related: tdf#147342 Copy layer's colorspace to window's colorspace
+    // This method is now called when the window's backing properties have
+    // changed so copy any colorspace changes.
+    fMetalLayer.colorspace = CGColorSpaceCreateWithName(kCGColorSpaceSRGB);
+
+    // Related tdf#145988 Reset layer's pixel format to MTLPixelFormatBGRA8Unorm
+    // Skia initally sets the layer's pixel format to be BGRA8888 but macOS
+    // may change the layer's pixel format when a window has moved to a screen
+    // with 30-bit color depth so reset it back to BGRA8888.
+    SAL_WARN_IF(fMetalLayer.pixelFormat != MTLPixelFormatBGRA8Unorm, "vcl.skia.metal", "CAMetalLayer pixel format is " << fMetalLayer.pixelFormat << " but should be " << MTLPixelFormatBGRA8Unorm << " (MTLPixelFormatBGRA8Unorm)");
+    fMetalLayer.pixelFormat = MTLPixelFormatBGRA8Unorm;
+
     fWidth = backingSize.width;
     fHeight = backingSize.height;
 }