public static BitmapSource CropScreen(BitmapSource fullScreenBtimap, CropViewBox viewBox)
 {
     try
     {
         var cropScreenbox = new Int32Rect(
             (int)Math.Round(viewBox.CropScreenbox.Left, 0),
             (int)Math.Round(viewBox.CropScreenbox.Top, 0),
             (int)Math.Round(viewBox.CropScreenbox.Width, 0),
             (int)Math.Round(viewBox.CropScreenbox.Height, 0));
         var extendBitmap  = ExtendFullScreenBitmap(fullScreenBtimap, ref cropScreenbox);
         var croppedBitmap = new CroppedBitmap(extendBitmap, cropScreenbox);
         if (viewBox.IsTransform)
         {
             //旋转、翻转变换
             var drawingVisual = new DrawingVisual();
             using (var context = drawingVisual.RenderOpen())
             {
                 var brush = new ImageBrush(croppedBitmap)
                 {
                     Stretch           = Stretch.None,
                     RelativeTransform = viewBox.RenderTransform,
                 };
                 context.DrawRectangle(brush, null, new Rect(0, 0, viewBox.TransformViewbox.Width, viewBox.TransformViewbox.Height));
             }
             var renderBitmap = new RenderTargetBitmap((int)viewBox.TransformViewbox.Width, (int)viewBox.TransformViewbox.Height, 96, 96, PixelFormats.Pbgra32);
             renderBitmap.Render(drawingVisual);
             croppedBitmap = new CroppedBitmap(renderBitmap, new Int32Rect((int)Math.Round(viewBox.CropViewbox.X, 0), (int)Math.Round(viewBox.CropViewbox.Y, 0), (int)Math.Round(viewBox.CropViewbox.Width, 0), (int)Math.Round(viewBox.CropViewbox.Height, 0)));
         }
         return(croppedBitmap);
     }
     catch (Exception ex)
     {
         Trace.WriteLine(ex.ToString());
         return(null);
     }
 }
 public static BitmapSource CropScreen(CropViewBox viewBox)
 {
     return(CropScreen(CopyScreen(), viewBox));
 }