Initial import

1 files changed, 73 insertions, 0 deletions

diff --git a/Xamarin.Forms.Platform.iOS/CADisplayLinkTicker.cs b/Xamarin.Forms.Platform.iOS/CADisplayLinkTicker.cs
new file mode 100644
index 00000000..29dd732a
--- /dev/null
+++ b/Xamarin.Forms.Platform.iOS/CADisplayLinkTicker.cs
@@ -0,0 +1,73 @@
+using System;
+using System.Collections.Concurrent;
+using System.Threading;
+#if __UNIFIED__
+using UIKit;
+using CoreAnimation;
+using Foundation;
+
+#else
+using MonoTouch.UIKit;
+using MonoTouch.CoreAnimation;
+using MonoTouch.Foundation;
+#endif
+
+namespace Xamarin.Forms.Platform.iOS
+{
+	internal class CADisplayLinkTicker : Ticker
+	{
+		readonly BlockingCollection<Action> _queue = new BlockingCollection<Action>();
+		CADisplayLink _link;
+
+		public CADisplayLinkTicker()
+		{
+			var thread = new Thread(StartThread);
+			thread.Start();
+		}
+
+		internal new static CADisplayLinkTicker Default
+		{
+			get { return Ticker.Default as CADisplayLinkTicker; }
+		}
+
+		public void Invoke(Action action)
+		{
+			_queue.Add(action);
+		}
+
+		protected override void DisableTimer()
+		{
+			if (_link != null)
+			{
+				_link.RemoveFromRunLoop(NSRunLoop.Current, NSRunLoop.NSRunLoopCommonModes);
+				_link.Dispose();
+			}
+			_link = null;
+		}
+
+		protected override void EnableTimer()
+		{
+			_link = CADisplayLink.Create(() => SendSignals());
+			_link.AddToRunLoop(NSRunLoop.Current, NSRunLoop.NSRunLoopCommonModes);
+		}
+
+		void StartThread()
+		{
+			while (true)
+			{
+				var action = _queue.Take();
+				var previous = UIApplication.CheckForIllegalCrossThreadCalls;
+				UIApplication.CheckForIllegalCrossThreadCalls = false;
+
+				CATransaction.Begin();
+				action.Invoke();
+
+				while (_queue.TryTake(out action))
+					action.Invoke();
+				CATransaction.Commit();
+
+				UIApplication.CheckForIllegalCrossThreadCalls = previous;
+			}
+		}
+	}
+}
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