First go at a zero-allocation

mono · Apr 27, 2020 · c7162db · c7162db
1 parent 354d85d
commit c7162db
Showing 1 changed file with 13 additions and 5 deletions.
diff --git a/source/SkiaSharp.Views/SkiaSharp.Views.UWP/SKSwapChainPanel.cs b/source/SkiaSharp.Views/SkiaSharp.Views.UWP/SKSwapChainPanel.cs
@@ -18,6 +18,9 @@ public class SKSwapChainPanel : AngleSwapChainPanel
 
 		private SKSizeI lastSize;
 
+		private SKPaintGLSurfaceEventArgs lastPaintEventArgs;
+		private bool reusePaintEventArgsInstance = true;
+
 		public SKSwapChainPanel()
 		{
 		}
@@ -80,14 +83,18 @@ protected override void OnRenderFrame(Rect rect)
 			{
 				surface = SKSurface.Create(context, renderTarget, surfaceOrigin, colorType);
 				canvas = surface.Canvas;
-			}
 
-			using (new SKAutoCanvasRestore(canvas, true))
-			{
-				// start drawing
-				OnPaintSurface(new SKPaintGLSurfaceEventArgs(surface, renderTarget, surfaceOrigin, colorType, glInfo));
+				// reset the args
+				lastPaintEventArgs = null;
 			}
 
+			// start drawing
+			if (!reusePaintEventArgsInstance || lastPaintEventArgs == null)
+				lastPaintEventArgs = new SKPaintGLSurfaceEventArgs(surface, renderTarget, surfaceOrigin, colorType, glInfo);
+
+			OnPaintSurface(lastPaintEventArgs);
+			canvas.RestoreToCount(0);
+
 			// update the control
 			canvas.Flush();
 			context.Flush();
@@ -97,6 +104,7 @@ protected override void OnDestroyingContext()
 		{
 			base.OnDestroyingContext();
 
+			lastPaintEventArgs = null;
 			lastSize = default;
 
 			canvas?.Dispose();