wpf - 如何从 RenderTargetBitmap bitblit 到 WriteableBitmap？

Question

我正在向 RenderTargetBitmap 渲染数十种视觉效果。每个都在它自己的 Rect 中呈现。我想要做的是将这些从 RenderTargetBitmap 实例呈现的 Rect 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，有没有办法快速将 rect 从 RenderTargetBitmap 复制到 WriteableBitmap ？

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));
}