Merge pull request #1553 from AvaloniaUI/feature/stop-renderer-on-minimize

Stop renderer on Window minimize.

src/Avalonia.Controls/Window.cs

@@ -145,11 +145,9 @@ namespace Avalonia.Controls
             : base(impl)
         {
             impl.Closing = HandleClosing;
+            impl.WindowStateChanged = HandleWindowStateChanged;
             _maxPlatformClientSize = PlatformImpl?.MaxClientSize ?? default(Size);
             Screens = new Screens(PlatformImpl?.Screen);
-
-            if (PlatformImpl != null)
-                PlatformImpl.WindowStateChanged = s => WindowState = s;
         }
         
         /// <inheritdoc/>
@@ -318,6 +316,20 @@ namespace Avalonia.Controls
             return args.Cancel;
         }
 
+        protected virtual void HandleWindowStateChanged(WindowState state)
+        {
+            WindowState = state;
+
+            if (state == WindowState.Minimized)
+            {
+                Renderer.Stop();
+            }
+            else
+            {
+                Renderer.Start();
+            }
+        }
+
         /// <summary>
         /// Hides the window but does not close it.
         /// </summary>