1 files changed, 91 insertions, 0 deletions
diff --git a/Xamarin.Forms.Controls/ControlGalleryPages/PinchGestureTestPage.cs b/Xamarin.Forms.Controls/ControlGalleryPages/PinchGestureTestPage.cs
new file mode 100644
index 00000000..44dd6ae8
--- /dev/null
+++ b/Xamarin.Forms.Controls/ControlGalleryPages/PinchGestureTestPage.cs
@@ -0,0 +1,91 @@
+using System;
+using System.Diagnostics;
+
+namespace Xamarin.Forms.Controls
+{
+	public class PinchToZoomContainer : ContentView
+	{
+		public PinchToZoomContainer ()
+		{
+			
+		}
+
+		public void AddPinch ()
+		{
+
+			var pinch = new PinchGestureRecognizer ();
+
+			double xOffset = 0;
+			double yOffset = 0;
+			double startScale = 1;
+
+			pinch.PinchUpdated += (sender, e) => {
+				
+				if (e.Status == GestureStatus.Started) {
+					startScale = Content.Scale;
+					Content.AnchorX = Content.AnchorY = 0;
+				}
+				if (e.Status == GestureStatus.Running) {
+
+					_currentScale += (e.Scale - 1) * startScale;
+					_currentScale = Math.Max (1, _currentScale);
+
+					var renderedX = Content.X + xOffset;
+					var deltaX = renderedX / Width;
+					var deltaWidth = Width / (Content.Width * startScale);
+					var originX = (e.ScaleOrigin.X - deltaX) * deltaWidth;
+
+					var renderedY = Content.Y + yOffset;
+					var deltaY = renderedY / Height;
+					var deltaHeight = Height / (Content.Height * startScale);
+					var originY = (e.ScaleOrigin.Y - deltaY) * deltaHeight;
+
+					double targetX = xOffset - (originX * Content.Width) * (_currentScale - startScale);
+					double targetY = yOffset - (originY * Content.Height) * (_currentScale - startScale);
+
+					Content.TranslationX = targetX.Clamp (-Content.Width * (_currentScale - 1), 0);
+					Content.TranslationY = targetY.Clamp (-Content.Height * (_currentScale - 1), 0);
+
+					Content.Scale = _currentScale;
+				}
+				if (e.Status == GestureStatus.Completed) {
+					xOffset = Content.TranslationX;
+					yOffset = Content.TranslationY;
+				}
+			};
+
+			GestureRecognizers.Add (pinch);
+		}
+
+		public bool AlwaysZoomCenter { get; set; }
+
+		double _currentScale = 1;
+	}
+
+	public class PinchGestureTestPage : ContentPage
+	{
+		public PinchGestureTestPage ()
+		{
+			var stack = new StackLayout { VerticalOptions = LayoutOptions.Start, HorizontalOptions = LayoutOptions.Center };
+			var textBoxScale = new Label { VerticalOptions = LayoutOptions.Start, HorizontalOptions = LayoutOptions.Center };
+			var textBox = new Label { VerticalOptions = LayoutOptions.Start, HorizontalOptions = LayoutOptions.Center };
+			var textBoxPoint = new Label { VerticalOptions = LayoutOptions.Start, HorizontalOptions = LayoutOptions.Center };
+			stack.Children.Add (textBox);
+			stack.Children.Add (textBoxScale);
+			stack.Children.Add (textBoxPoint);
+
+			var box = new Image { Source = "crimson.jpg", BackgroundColor = Color.Red, WidthRequest = 200, HeightRequest = 200, VerticalOptions = LayoutOptions.Center, HorizontalOptions = LayoutOptions.Center };
+
+			var zoomContainer = new PinchToZoomContainer ();
+			zoomContainer.Content = box;
+
+			var btn = new Button { Text = "add pinch gesture", Command = new Command (() => zoomContainer.AddPinch ()) };
+			var btnRemove = new Button { Text = "remove pinch gesture", Command = new Command (() => zoomContainer.GestureRecognizers.Clear ()) };
+
+			Content = new StackLayout { Children = { btn, btnRemove, new Grid { Children = { zoomContainer }, Padding = new Thickness (20) } } };
+		}
+
+		double _currentScale = 1;
+	}
+}
+