如何从 RenderTargetBitmap 位传输到 WriteableBitmap？

Question

我正在将数十个视觉效果渲染到 RenderTargetBitmap。每个都在它自己的矩形中渲染。 我想要做的是将 RenderTargetBitmap 实例渲染的这些矩形区域之一复制到 WriteableBitmap 的同一区域...快速复制矩形像素或 smth。像那样。

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));
}