protected override void OnPaint(PaintEventArgs e) { if (designMode) { e.Graphics.Clear(BackColor); return; } base.OnPaint(e); MakeCurrent(); // create the contexts if not done already if (grContext == null) { var glInterface = GRGlInterface.CreateDefaultInterface(); grContext = GRContext.CreateGl(glInterface); } // get the new surface size var newSize = new SKSizeI(Width, Height); // manage the drawing surface if (renderTarget == null || lastSize != newSize || !renderTarget.IsValid) { // create or update the dimensions lastSize = newSize; GL.GetInteger(GetPName.FramebufferBinding, out var framebuffer); GL.GetInteger(GetPName.StencilBits, out var stencil); GL.GetInteger(GetPName.Samples, out var samples); var maxSamples = grContext.GetMaxSurfaceSampleCount(colorType); if (samples > maxSamples) { samples = maxSamples; } glInfo = new GRGlFramebufferInfo((uint)framebuffer, colorType.ToGlSizedFormat()); // destroy the old surface surface?.Dispose(); surface = null; canvas = null; // re-create the render target renderTarget?.Dispose(); renderTarget = new GRBackendRenderTarget(newSize.Width, newSize.Height, samples, stencil, glInfo); } // create the surface if (surface == null) { surface = SKSurface.Create(grContext, renderTarget, surfaceOrigin, colorType); canvas = surface.Canvas; } using (new SKAutoCanvasRestore(canvas, true)) { // start drawing OnPaintSurface(new SKPaintGLSurfaceEventArgs(surface, renderTarget, surfaceOrigin, colorType)); } // update the control canvas.Flush(); SwapBuffers(); }