Exposing GRContext on the various GL views. Issue #358

source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.Native.Shared/SKCanvasViewRendererBase.cs

@@ -165,9 +165,9 @@ namespace SkiaSharp.Views.Forms
 		}
 
 		// the user asked for the size
-		private void OnGetCanvasSize(object sender, GetCanvasSizeEventArgs e)
+		private void OnGetCanvasSize(object sender, GetPropertyValueEventArgs<SKSize> e)
 		{
-			e.CanvasSize = Control?.CanvasSize ?? SKSize.Empty;
+			e.Value = Control?.CanvasSize ?? SKSize.Empty;
 		}
 	}
 }

source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.Native.Shared/SKGLViewRendererBase.cs

@@ -51,6 +51,8 @@ namespace SkiaSharp.Views.Forms
 #endif
 		}
 
+		public GRContext GRContext => Control.GRContext;
+
 #if __IOS__
 		protected void SetDisablesUserInteraction(bool disablesUserInteraction)
 		{
@@ -67,6 +69,7 @@ namespace SkiaSharp.Views.Forms
 				// unsubscribe from events
 				oldController.SurfaceInvalidated -= OnSurfaceInvalidated;
 				oldController.GetCanvasSize -= OnGetCanvasSize;
+				oldController.GetGRContext -= OnGetGRContext;
 			}
 
 			if (e.NewElement != null)
@@ -90,6 +93,7 @@ namespace SkiaSharp.Views.Forms
 				// subscribe to events from the user
 				newController.SurfaceInvalidated += OnSurfaceInvalidated;
 				newController.GetCanvasSize += OnGetCanvasSize;
+				newController.GetGRContext += OnGetGRContext;
 
 				// start the rendering
 				SetupRenderLoop(false);
@@ -163,9 +167,15 @@ namespace SkiaSharp.Views.Forms
 		}
 
 		// the user asked for the size
-		private void OnGetCanvasSize(object sender, GetCanvasSizeEventArgs e)
+		private void OnGetCanvasSize(object sender, GetPropertyValueEventArgs<SKSize> e)
 		{
-			e.CanvasSize = Control?.CanvasSize ?? SKSize.Empty;
+			e.Value = Control?.CanvasSize ?? SKSize.Empty;
+		}
+
+		// the user asked for the current GRContext
+		private void OnGetGRContext(object sender, GetPropertyValueEventArgs<GRContext> e)
+		{
+			e.Value = Control?.GRContext;
 		}
 
 		private void OnPaintSurface(object sender, SKNativePaintGLSurfaceEventArgs e)

source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.Shared/RendererTypes.cs

@@ -2,8 +2,8 @@
 
 namespace SkiaSharp.Views.Forms
 {
-	internal class GetCanvasSizeEventArgs : EventArgs
+	internal class GetPropertyValueEventArgs<T> : EventArgs
 	{
-		public SKSize CanvasSize { get; set; }
+		public T Value { get; set; }
 	}
 }

source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.Shared/SKCanvasView.cs

@@ -20,7 +20,7 @@ namespace SkiaSharp.Views.Forms
 
 		// the native listens to this event
 		private event EventHandler SurfaceInvalidated;
-		private event EventHandler<GetCanvasSizeEventArgs> GetCanvasSize;
+		private event EventHandler<GetPropertyValueEventArgs<SKSize>> GetCanvasSize;
 
 		// the user asks the for the size
 		public SKSize CanvasSize
@@ -28,9 +28,9 @@ namespace SkiaSharp.Views.Forms
 			get
 			{
 				// send a mesage to the native view
-				var args = new GetCanvasSizeEventArgs();
+				var args = new GetPropertyValueEventArgs<SKSize>();
 				GetCanvasSize?.Invoke(this, args);
-				return args.CanvasSize;
+				return args.Value;
 			}
 		}
 
@@ -73,7 +73,7 @@ namespace SkiaSharp.Views.Forms
 			remove { SurfaceInvalidated -= value; }
 		}
 
-		event EventHandler<GetCanvasSizeEventArgs> ISKCanvasViewController.GetCanvasSize
+		event EventHandler<GetPropertyValueEventArgs<SKSize>> ISKCanvasViewController.GetCanvasSize
 		{
 			add { GetCanvasSize += value; }
 			remove { GetCanvasSize -= value; }
@@ -99,7 +99,7 @@ namespace SkiaSharp.Views.Forms
 	{
 		// the native listens to this event
 		event EventHandler SurfaceInvalidated;
-		event EventHandler<GetCanvasSizeEventArgs> GetCanvasSize;
+		event EventHandler<GetPropertyValueEventArgs<SKSize>> GetCanvasSize;
 
 		// the native view tells the user to repaint
 		void OnPaintSurface(SKPaintSurfaceEventArgs e);

source/SkiaSharp.Views.Forms/SkiaSharp.Views.Forms.Shared/SKGLView.cs

@@ -32,7 +32,8 @@ namespace SkiaSharp.Views.Forms
 
 		// the native listens to this event
 		private event EventHandler SurfaceInvalidated;
-		private event EventHandler<GetCanvasSizeEventArgs> GetCanvasSize;
+		private event EventHandler<GetPropertyValueEventArgs<SKSize>> GetCanvasSize;
+		private event EventHandler<GetPropertyValueEventArgs<GRContext>> GetGRContext;
 
 		// the user asks the for the size
 		public SKSize CanvasSize
@@ -40,9 +41,21 @@ namespace SkiaSharp.Views.Forms
 			get
 			{
 				// send a mesage to the native view
-				var args = new GetCanvasSizeEventArgs();
+				var args = new GetPropertyValueEventArgs<SKSize>();
 				GetCanvasSize?.Invoke(this, args);
-				return args.CanvasSize;
+				return args.Value;
+			}
+		}
+
+		// the user asks the for the current GRContext
+		public GRContext GRContext
+		{
+			get
+			{
+				// send a mesage to the native view
+				var args = new GetPropertyValueEventArgs<GRContext>();
+				GetGRContext?.Invoke(this, args);
+				return args.Value;
 			}
 		}
 
@@ -73,12 +86,18 @@ namespace SkiaSharp.Views.Forms
 			remove { SurfaceInvalidated -= value; }
 		}
 
-		event EventHandler<GetCanvasSizeEventArgs> ISKGLViewController.GetCanvasSize
+		event EventHandler<GetPropertyValueEventArgs<SKSize>> ISKGLViewController.GetCanvasSize
 		{
 			add { GetCanvasSize += value; }
 			remove { GetCanvasSize -= value; }
 		}
 
+		event EventHandler<GetPropertyValueEventArgs<GRContext>> ISKGLViewController.GetGRContext
+		{
+			add { GetGRContext += value; }
+			remove { GetGRContext -= value; }
+		}
+
 		void ISKGLViewController.OnPaintSurface(SKPaintGLSurfaceEventArgs e)
 		{
 			OnPaintSurface(e);
@@ -99,7 +118,8 @@ namespace SkiaSharp.Views.Forms
 	{
 		// the native listens to this event
 		event EventHandler SurfaceInvalidated;
-		event EventHandler<GetCanvasSizeEventArgs> GetCanvasSize;
+		event EventHandler<GetPropertyValueEventArgs<SKSize>> GetCanvasSize;
+		event EventHandler<GetPropertyValueEventArgs<GRContext>> GetGRContext;
 
 		// the native view tells the user to repaint
 		void OnPaintSurface(SKPaintGLSurfaceEventArgs e);

source/SkiaSharp.Views/SkiaSharp.Views.Android/SKGLSurfaceView.cs

@@ -32,6 +32,8 @@ namespace SkiaSharp.Views.Android
 
 		public SKSize CanvasSize => renderer.CanvasSize;
 
+		public GRContext GRContext => renderer.GRContext;
+
 		public virtual void SetRenderer(ISKRenderer renderer)
 		{
 			skRenderer = renderer;

source/SkiaSharp.Views/SkiaSharp.Views.Android/SKGLSurfaceViewRenderer.cs

@@ -13,6 +13,8 @@ namespace SkiaSharp.Views.Android
 
 		public SKSize CanvasSize => new SKSize(renderTarget.Width, renderTarget.Height);
 
+		public GRContext GRContext => context;
+
 		protected abstract void OnDrawFrame(SKSurface surface, GRBackendRenderTargetDesc renderTarget);
 
 		public void OnDrawFrame(IGL10 gl)

source/SkiaSharp.Views/SkiaSharp.Views.AppleiOS/SKGLLayer.cs

@@ -28,6 +28,8 @@ namespace SkiaSharp.Views.iOS
 
 		public SKSize CanvasSize => new SKSize(renderTarget.Width, renderTarget.Height);
 
+		public GRContext GRContext => context;
+
 		public virtual void Render()
 		{
 			if (glContext == null)

source/SkiaSharp.Views/SkiaSharp.Views.AppleiOS/SKGLView.cs

@@ -75,6 +75,8 @@ namespace SkiaSharp.Views.iOS
 
 		public SKSize CanvasSize => new SKSize(renderTarget.Width, renderTarget.Height);
 
+		public GRContext GRContext => context;
+
 		public new void DrawInRect(GLKView view, CGRect rect)
 		{
 			if (designMode)

source/SkiaSharp.Views/SkiaSharp.Views.Desktop/SKGLControl.cs

@@ -21,6 +21,8 @@ namespace SkiaSharp.Views.Desktop
 
 		public SKSize CanvasSize => new SKSize(renderTarget.Width, renderTarget.Height);
 
+		public GRContext GRContext => grContext;
+
 		public event EventHandler<SKPaintGLSurfaceEventArgs> PaintSurface;
 		
 		protected override void OnPaint(PaintEventArgs e)

source/SkiaSharp.Views/SkiaSharp.Views.Mac/SKGLLayer.cs

@@ -20,6 +20,8 @@ namespace SkiaSharp.Views.Mac
 
 		public SKSize CanvasSize => new SKSize(renderTarget.Width, renderTarget.Height);
 
+		public GRContext GRContext => context;
+
 		public event EventHandler<SKPaintGLSurfaceEventArgs> PaintSurface;
 
 		public virtual void DrawInSurface(SKSurface surface, GRBackendRenderTargetDesc renderTarget)

source/SkiaSharp.Views/SkiaSharp.Views.Mac/SKGLView.cs

@@ -63,6 +63,8 @@ namespace SkiaSharp.Views.Mac
 
 		public SKSize CanvasSize => new SKSize(renderTarget.Width, renderTarget.Height);
 
+		public GRContext GRContext => context;
+
 		public override void PrepareOpenGL()
 		{
 			base.PrepareOpenGL();

source/SkiaSharp.Views/SkiaSharp.Views.UWP/SKSwapChainPanel.cs

@@ -25,6 +25,8 @@ namespace SkiaSharp.Views.UWP
 
 		public SKSize CanvasSize => new SKSize(renderTarget.Width, renderTarget.Height);
 
+		public GRContext GRContext => context;
+
 		protected override Size ArrangeOverride(Size finalSize)
 		{
 			var arrange = base.ArrangeOverride(finalSize);