From 54c29900c15afce47459f77875412494d1b4415b Mon Sep 17 00:00:00 2001
From: Matthew Leibowitz <mattleibow@live.com>
Date: Thu, 15 Sep 2016 17:51:13 +0200
Subject: [PATCH] Added a view to UWP forms

---
 .../SKViewRenderer.cs                         | 78 +++++++++++++++++++
 .../SkiaSharp.Views.Forms.UWP.csproj          |  1 +
 .../SkiaSharp.Views.Forms.UWP.nuget.targets   | 11 +++
 .../SkiaSharp.Views.Forms.UWP/project.json    |  5 +-
 4 files changed, 94 insertions(+), 1 deletion(-)
 create mode 100644 source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SKViewRenderer.cs
 create mode 100644 source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SkiaSharp.Views.Forms.UWP.nuget.targets

diff --git a/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SKViewRenderer.cs b/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SKViewRenderer.cs
new file mode 100644
index 00000000..f94d98f7
--- /dev/null
+++ b/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SKViewRenderer.cs
@@ -0,0 +1,78 @@
+using System;
+using Xamarin.Forms;
+using Xamarin.Forms.Platform.UWP;
+
+using SKFormsView = SkiaSharp.Views.Forms.SKView;
+using SKNativeView = SkiaSharp.Views.SKXamlCanvas;
+
+[assembly: ExportRenderer(typeof(SKFormsView), typeof(SkiaSharp.Views.Forms.SKViewRenderer))]
+
+namespace SkiaSharp.Views.Forms
+{
+	internal class SKViewRenderer : ViewRenderer<SKFormsView, SKNativeView>
+	{
+		protected override void OnElementChanged(ElementChangedEventArgs<SKFormsView> e)
+		{
+			if (e.OldElement != null)
+			{
+				var oldController = (ISKViewController)e.OldElement;
+
+				// unsubscribe from events
+				oldController.SurfaceInvalidated -= OnSurfaceInvalidated;
+			}
+
+			if (e.NewElement != null)
+			{
+				var newController = (ISKViewController)e.NewElement;
+
+				// create the native view
+				var view = new InternalView(newController);
+				SetNativeControl(view);
+
+				// subscribe to events from the user
+				newController.SurfaceInvalidated += OnSurfaceInvalidated;
+
+				// paint for the first time
+				Control.Invalidate();
+			}
+
+			base.OnElementChanged(e);
+		}
+
+		protected override void Dispose(bool disposing)
+		{
+			// detach all events before disposing
+			var controller = (ISKViewController)Element;
+			if (controller != null)
+			{
+				controller.SurfaceInvalidated -= OnSurfaceInvalidated;
+			}
+
+			base.Dispose(disposing);
+		}
+
+		private void OnSurfaceInvalidated(object sender, EventArgs eventArgs)
+		{
+			// repaint the native control
+			Control.Invalidate();
+		}
+
+		private class InternalView : SKNativeView
+		{
+			private readonly ISKViewController controller;
+
+			public InternalView(ISKViewController controller)
+			{
+				this.controller = controller;
+			}
+
+			protected override void OnPaintSurface(SkiaSharp.Views.SKPaintSurfaceEventArgs e)
+			{
+				base.OnPaintSurface(e);
+
+				// the control is being repainted, let the user know
+				controller.OnPaintSurface(new SKPaintSurfaceEventArgs(e.Surface, e.Info));
+			}
+		}
+	}
+}
diff --git a/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SkiaSharp.Views.Forms.UWP.csproj b/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SkiaSharp.Views.Forms.UWP.csproj
index 832de6c4..714c63ba 100644
--- a/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SkiaSharp.Views.Forms.UWP.csproj
+++ b/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SkiaSharp.Views.Forms.UWP.csproj
@@ -108,6 +108,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="SKViewRenderer.cs" />
     <EmbeddedResource Include="Properties\SkiaSharp.Views.Forms.UWP.rd.xml" />
   </ItemGroup>
   <Import Project="..\SkiaSharp.Views.Forms.Shared\SkiaSharp.Views.Forms.Shared.projitems" Label="Shared" />
diff --git a/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SkiaSharp.Views.Forms.UWP.nuget.targets b/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SkiaSharp.Views.Forms.UWP.nuget.targets
new file mode 100644
index 00000000..ae7688e0
--- /dev/null
+++ b/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/SkiaSharp.Views.Forms.UWP.nuget.targets
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8" standalone="no"?>
+<Project ToolsVersion="14.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup Condition="'$(NuGetPackageRoot)' == ''">
+    <NuGetPackageRoot>$(UserProfile)\.nuget\packages\</NuGetPackageRoot>
+  </PropertyGroup>
+  <ImportGroup>
+    <Import Project="$(NuGetPackageRoot)\SkiaSharp\1.54.0.1\build\uap10.0\SkiaSharp.targets" Condition="Exists('$(NuGetPackageRoot)\SkiaSharp\1.54.0.1\build\uap10.0\SkiaSharp.targets')" />
+    <Import Project="$(NuGetPackageRoot)\SkiaSharp.Views\1.54.0.1-beta1\build\uap10.0\SkiaSharp.Views.targets" Condition="Exists('$(NuGetPackageRoot)\SkiaSharp.Views\1.54.0.1-beta1\build\uap10.0\SkiaSharp.Views.targets')" />
+    <Import Project="$(NuGetPackageRoot)\Xamarin.Forms\2.3.0.49\build\portable-win+net45+wp80+win81+wpa81+MonoAndroid10+MonoTouch10+Xamarin.iOS10\Xamarin.Forms.targets" Condition="Exists('$(NuGetPackageRoot)\Xamarin.Forms\2.3.0.49\build\portable-win+net45+wp80+win81+wpa81+MonoAndroid10+MonoTouch10+Xamarin.iOS10\Xamarin.Forms.targets')" />
+  </ImportGroup>
+</Project>
\ No newline at end of file
diff --git a/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/project.json b/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/project.json
index 92d14561..4a08dba0 100644
--- a/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/project.json
+++ b/source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.UWP/project.json
@@ -1,6 +1,9 @@
 {
   "dependencies": {
-    "Microsoft.NETCore.UniversalWindowsPlatform": "5.1.0"
+    "Microsoft.NETCore.UniversalWindowsPlatform": "5.1.0",
+    "SkiaSharp": "1.54.0.1",
+    "SkiaSharp.Views": "1.54.0.1-beta1",
+    "Xamarin.Forms": "2.3.0.49"
   },
   "frameworks": {
     "uap10.0": {}