如何从RenderTargetBitmap到WriteableBitmap的bitblit？

Question

我正在向RenderTargetBitmap渲染几十个视觉效果。每一个都在它自己的Rect中呈现。我想要做的是将其中一个从RenderTargetBitmap实例渲染的矩形区域复制到WriteableBitmap...Fast复制矩形像素或smth的相同区域中。就像这样。

那么，有没有一种方法可以快速地将rect从RenderTargetBitmap复制到WriteableBitmap呢？

Answer 1

通过将整个RenderTargetBitmap复制到WriteableBitmap来解决，如下所示：

 protected override void OnRender(DrawingContext drawingContext)
 {
   if (ActualWidth == 0 || ActualHeight == 0) return;
   // Create destination bitmap
   wb = new WriteableBitmap((int) ActualWidth, (int) ActualHeight, 96, 96, PixelFormats.Pbgra32, null);
   wb.Lock();
   rtb = new RenderTargetBitmap(wb.PixelWidth, wb.PixelHeight, wb.DpiX, wb.DpiY, PixelFormats.Pbgra32);
   foreach (MyVisual visual in visuals)
   {
     visual.Render(rtb);
   }

   rtb.CopyPixels(new Int32Rect(0,0, rtb.PixelWidth, rtb.PixelHeight), 
   wb.BackBuffer,
   wb.BackBufferStride * wb.PixelHeight,  wb.BackBufferStride);

   wb.AddDirtyRect(new Int32Rect(0, 0, (int)ActualWidth, (int)ActualHeight));
   wb.Unlock();

   drawingContext.DrawImage(wb, new Rect(0, 0, ActualWidth, ActualHeight));
}