clipViewerElement static method
Converts Rectangle<num> to ViewerElement<Rectangle<num>>.
Implementation
static ViewerElement<Rectangle<num>> clipViewerElement(Rectangle<num>? clip,
    [Color? color]) {
  return ViewerElement<Rectangle<num>>(clip, color,
      valueCopier: (v) => v == null
          ? null
          : Rectangle<num>(v.left, v.top, v.width, v.height));
}