Input of ClippingRegion Supports Variable

Target.ClippingRegion defines the clipping rectangle, in pixels, relative to the UiElement, in the following directions: left, top, right, bottom. It just supports both positive and negative numbers now.
But sometimes, we need to change it dynamically,
for example, have many equidistant target in screen.
Therefore I hope input of ClippingRegion will be supported variable,
or other ways can be used to change it dynamically.