Arranges the content of a Viewbox element.
Protected Overrides Function ArrangeOverride ( _
arrangeSize As Size _
) As Size
The Size this element uses to arrange its child elements.
Viewbox always sets its Child to the DesiredSize. It then computes and applies a transformation from that Size to the available space. Viewbox determines available space by subtracting the margin of its Child from the input Size of its elements.