private static PaintTransform FromSourceAndDest(Rect srcRect, Rect dstRect)
{
return new PaintTransform(-srcRect.left, -srcRect.top,
srcRect.right - srcRect.left, srcRect.bottom - srcRect.top,
-dstRect.left, -dstRect.top,
dstRect.right - dstRect.left, dstRect.bottom - dstRect.top);
}
}