Initial import

1 files changed, 76 insertions, 0 deletions

diff --git a/Xamarin.Forms.Platform.Android/PinchGestureHandler.cs b/Xamarin.Forms.Platform.Android/PinchGestureHandler.cs
new file mode 100644
index 00000000..bc06531c
--- /dev/null
+++ b/Xamarin.Forms.Platform.Android/PinchGestureHandler.cs
@@ -0,0 +1,76 @@
+using System;
+using System.Linq;
+
+namespace Xamarin.Forms.Platform.Android
+{
+	internal class PinchGestureHandler
+	{
+		double _pinchStartingScale = 1;
+
+		public PinchGestureHandler(Func<View> getView)
+		{
+			GetView = getView;
+		}
+
+		public bool IsPinchSupported
+		{
+			get
+			{
+				View view = GetView();
+				return view != null && view.GestureRecognizers.GetGesturesFor<PinchGestureRecognizer>().Any();
+			}
+		}
+
+		Func<View> GetView { get; }
+
+		// A View can have at most one pinch gesture, so we just need to look for one (or none)
+		PinchGestureRecognizer PinchGesture => GetView()?.GestureRecognizers.GetGesturesFor<PinchGestureRecognizer>().FirstOrDefault();
+
+		public bool OnPinch(float scale, Point scalePoint)
+		{
+			View view = GetView();
+
+			if (view == null)
+				return false;
+
+			PinchGestureRecognizer pinchGesture = PinchGesture;
+			if (pinchGesture == null)
+				return true;
+
+			var scalePointTransformed = new Point(scalePoint.X / view.Width, scalePoint.Y / view.Height);
+			((IPinchGestureController)pinchGesture).SendPinch(view, 1 + (scale - 1) * _pinchStartingScale, scalePointTransformed);
+
+			return true;
+		}
+
+		public void OnPinchEnded()
+		{
+			View view = GetView();
+
+			if (view == null)
+				return;
+
+			PinchGestureRecognizer pinchGesture = PinchGesture;
+			((IPinchGestureController)pinchGesture)?.SendPinchEnded(view);
+		}
+
+		public bool OnPinchStarted(Point scalePoint)
+		{
+			View view = GetView();
+
+			if (view == null)
+				return false;
+
+			PinchGestureRecognizer pinchGesture = PinchGesture;
+			if (pinchGesture == null)
+				return false;
+
+			_pinchStartingScale = view.Scale;
+
+			var scalePointTransformed = new Point(scalePoint.X / view.Width, scalePoint.Y / view.Height);
+
+			((IPinchGestureController)pinchGesture).SendPinchStarted(view, scalePointTransformed);
+			return true;
+		}
+	}
+}
\ No newline at end of file