WPF Clip

            UIElement elem = canvas1;

            elem.ClipToBounds = false;
            Size s = new Size(260, 200);

            int width  = (int)dockPanel1.Width +100;
            int height = (int)dockPanel1.Height +100;
            elem.InvalidateVisual();
            elem.Measure(s);
            elem.Arrange(new Rect(s));

            RenderTargetBitmap bmp = new RenderTargetBitmap(width, height, 96d, 96d, PixelFormats.Pbgra32);
            bmp.Render(elem);
            elem.ClipToBounds = true;

            var encoder = new BmpBitmapEncoder();

            encoder.Frames.Add(BitmapFrame.Create(bmp));

            FileStream fs = new FileStream("image.bmp", FileMode.Create);



            encoder.Save(fs);

            fs.Close();