c# - 将画布转换为 WPF 中可写位图的最快方法？

Question

我目前有一个可写位图图像和带有绘图的画布，我想将图像发送给对等方。为了减少带宽，我想将画布转换为可写位图，因此我可以将两个图像都blit到一个新的可写位图。问题是我找不到转换画布的好方法。所以想问问有没有直接的办法可以把canvas转成writeablebitmap类。

Answer 1

这取自这篇博文，但不是写入文件，而是写入 WriteableBitmap。

public WriteableBitmap SaveAsWriteableBitmap(Canvas surface)
{
    if (surface == null) return null;

    // Save current canvas transform
    Transform transform = surface.LayoutTransform;
    // reset current transform (in case it is scaled or rotated)
    surface.LayoutTransform = null;

    // Get the size of canvas
    Size size = new Size(surface.ActualWidth, surface.ActualHeight);
    // Measure and arrange the surface
    // VERY IMPORTANT
    surface.Measure(size);
    surface.Arrange(new Rect(size));

    // Create a render bitmap and push the surface to it
    RenderTargetBitmap renderBitmap = new RenderTargetBitmap(
      (int)size.Width, 
      (int)size.Height, 
      96d, 
      96d, 
      PixelFormats.Pbgra32);
    renderBitmap.Render(surface);


    //Restore previously saved layout
    surface.LayoutTransform = transform;

    //create and return a new WriteableBitmap using the RenderTargetBitmap
    return new WriteableBitmap(renderBitmap);

}