perf(macOS): Avoid calling NSView.Layer getter more than once / method

src/Uno.UI/Controls/BindableNSView.macOS.cs

@@ -58,9 +58,10 @@ public BindableNSView()
 		{
 			Initialize();
 			WantsLayer = true;
-			if (Layer != null)
+			var layer = Layer;
+			if (layer != null)
 			{
-				Layer.MasksToBounds = false;
+				layer.MasksToBounds = false;
 			}
 		}
 

src/Uno.UI/Media/NativeRenderTransformAdapter.iOSmacOS.cs

@@ -35,7 +35,8 @@ partial void Initialized()
 			if (Owner is FrameworkElement element && !element.IsLoaded)
 			{
 				_isDeferring = true;
-				element.Layer.Opacity = 0;
+				var layer = element.Layer;
+				layer.Opacity = 0;
 				element.Loaded += DeferredInitialize;
 
 				_deferredInitialization = Disposable.Create(CompleteInitialization);
@@ -56,7 +57,7 @@ void CompleteInitialization()
 					element.Loaded -= DeferredInitialize;
 
 					_isDeferring = false;
-					element.Layer.Opacity = 1;
+					layer.Opacity = 1;
 
 					if (!_isDisposed)
 					{
@@ -77,13 +78,14 @@ void CompleteInitialization()
 
 		private void InitializeOrigin()
 		{
-			var oldFrame = Owner.Layer.Frame;
+			var layer = Owner.Layer;
+			var oldFrame = layer.Frame;
 
-			Owner.Layer.AnchorPoint = CurrentOrigin;
+			layer.AnchorPoint = CurrentOrigin;
 
 			// Restore the old frame to correct the offset potentially introduced by changing AnchorPoint. This is safe to do since we know
 			// that the transform is currently identity.
-			Owner.Layer.Frame = oldFrame;
+			layer.Frame = oldFrame;
 		}
 
 		partial void Apply(bool isSizeChanged, bool isOriginChanged)
@@ -94,14 +96,15 @@ partial void Apply(bool isSizeChanged, bool isOriginChanged)
 				return;
 			}
 #endif
+			var layer = Owner.Layer;
 			if (Transform.IsAnimating)
 			{
 				// While animating the transform, we let the Animator apply the transform by itself, so do not update the Transform
 				if (!_wasAnimating)
 				{
 					// At the beginning of the animation make sure we disable all properties of the transform
-					Owner.Layer.AnchorPoint = GPUFloatValueAnimator.GetAnchorForAnimation(Transform, CurrentOrigin, CurrentSize);
-					Owner.Layer.Transform = CoreAnimation.CATransform3D.Identity;
+					layer.AnchorPoint = GPUFloatValueAnimator.GetAnchorForAnimation(Transform, CurrentOrigin, CurrentSize);
+					layer.Transform = CoreAnimation.CATransform3D.Identity;
 
 					_wasAnimating = true;
 				}
@@ -112,8 +115,8 @@ partial void Apply(bool isSizeChanged, bool isOriginChanged)
 			{
 				// Make sure to fully restore the transform at the end of an animation
 
-				Owner.Layer.AnchorPoint = CurrentOrigin;
-				Owner.Layer.Transform = _transform = Transform.MatrixCore.ToTransform3D();
+				layer.AnchorPoint = CurrentOrigin;
+				layer.Transform = _transform = Transform.MatrixCore.ToTransform3D();
 
 				_wasAnimating = false;
 
@@ -124,15 +127,15 @@ partial void Apply(bool isSizeChanged, bool isOriginChanged)
 			{
 				// As we use the 'AnchorPoint', the transform matrix is independent of the size of the control
 				// But the layouter expects from us that we restore the transform on each measuring phase
-				Owner.Layer.Transform = _transform;
+				layer.Transform = _transform;
 			}
 			else if (isOriginChanged)
 			{
-				Owner.Layer.AnchorPoint = CurrentOrigin;
+				layer.AnchorPoint = CurrentOrigin;
 			}
 			else
 			{
-				Owner.Layer.Transform = _transform = Transform.MatrixCore.ToTransform3D();
+				layer.Transform = _transform = Transform.MatrixCore.ToTransform3D();
 			}
 		}
 

src/Uno.UI/UI/Xaml/Controls/Layouter/Layouter.macOS.cs

@@ -111,6 +111,7 @@ private IDisposable SettingFrame(View view)
 
 			// If NSView.Transform is not identity, then modifying the frame will give undefined behavior. (https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIView_Class/#//apple_ref/occ/instp/NSView/transform)
 			// We have either already applied the transform to the new frame, or we will reset the transform straight after.
+			// FIXME: view.Layer called twice (thrice with above check)
 			var transform = view.Layer.Transform;
 			view.Layer.Transform = CATransform3D.Identity;
 			return Disposable.Create(reapplyTransform);

src/Uno.UI/UI/Xaml/IFrameworkElementImplementation.macOS.tt

@@ -366,12 +366,13 @@ namespace <#= mixin.NamespaceName #>
 #endif
 
 				CoreAnimation.CATransform3D? oldTransform = null;
-				if (Layer != null && !Layer.Transform.IsIdentity)
+				var layer = Layer;
+				if (layer != null && !layer.Transform.IsIdentity)
 				{
 					// If NSView.Transform is not identity, then modifying the frame will give undefined behavior. (https://developer.apple.com/library/ios/documentation/UIKit/Reference/NSView_Class/#//apple_ref/occ/instp/NSView/transform)
 					// We reapply the transform based on the new size straight after.
-					oldTransform = Layer.Transform;
-					Layer.Transform = CoreAnimation.CATransform3D.Identity;
+					oldTransform = layer.Transform;
+					layer.Transform = CoreAnimation.CATransform3D.Identity;
 				}
 
 				base.Frame = value;
@@ -389,13 +390,13 @@ namespace <#= mixin.NamespaceName #>
 					else if (oldTransform.HasValue)
 					{
 						// We grudgingly support setting the native transform directly without going through RenderTransform.
-						Layer.Transform = oldTransform.Value;
+						layer.Transform = oldTransform.Value;
 					}
 				}
 				else if (oldTransform.HasValue)
 				{
 					// We grudgingly support setting the native transform directly without going through RenderTransform.
-					Layer.Transform = oldTransform.Value;
+					layer.Transform = oldTransform.Value;
 				}
 			}
 		}
@@ -882,17 +883,18 @@ namespace <#= mixin.NamespaceName #>
 			{
 				WantsLayer = true;
 
+				var layer = Layer;
 				if(e.NewValue is SolidColorBrush scb)
 				{
-					Layer.BackgroundColor = scb.ColorWithOpacity;
+					layer.BackgroundColor = scb.ColorWithOpacity;
 
 					_brushColorChanged.Disposable = scb.RegisterDisposablePropertyChangedCallback(
 						SolidColorBrush.ColorProperty,
-						(s, colorArg) => Layer.BackgroundColor = (s as SolidColorBrush).ColorWithOpacity
+						(s, colorArg) => layer.BackgroundColor = (s as SolidColorBrush).ColorWithOpacity
 					);
 					_brushOpacityChanged.Disposable = scb.RegisterDisposablePropertyChangedCallback(
 						SolidColorBrush.OpacityProperty,
-						(s, colorArg) => Layer.BackgroundColor = (s as SolidColorBrush).ColorWithOpacity
+						(s, colorArg) => layer.BackgroundColor = (s as SolidColorBrush).ColorWithOpacity
 					);
 				}
 				else
@@ -901,15 +903,15 @@ namespace <#= mixin.NamespaceName #>
 					_brushOpacityChanged.Disposable = null;
 					if(e.NewValue is GradientBrush gb)
 					{
-						Layer.BackgroundColor = gb.FallbackColorWithOpacity;
+						layer.BackgroundColor = gb.FallbackColorWithOpacity;
 					}
 					else
 					{
 						if (this.Log().IsEnabled(Uno.Foundation.Logging.LogLevel.Warning))
 						{
 							this.Log().Warn("Brush is not a SolidColorBrush, ignoring");
 						}
-						Layer.BackgroundColor = SolidColorBrushHelper.Transparent.Color;
+						layer.BackgroundColor = SolidColorBrushHelper.Transparent.Color;
 					}
 				}
 			}

src/Uno.UI/UI/Xaml/UIElement.macOS.cs

@@ -262,18 +262,16 @@ partial void ApplyNativeClip(Rect rect)
 			{
 				if (!ClippingIsSetByCornerRadius)
 				{
-					if (Layer != null)
-					{
-						this.Layer.Mask = null;
-					}
+					Layer.Mask = null;
 				}
 				return;
 			}
 
 			WantsLayer = true;
-			if (Layer != null)
+			var layer = Layer;
+			if (layer != null)
 			{
-				this.Layer.Mask = new CAShapeLayer
+				layer.Mask = new CAShapeLayer
 				{
 					Path = CGPath.FromRect(rect.ToCGRect())
 				};