paintBounds

The area this decorator and its content can paint, in a box of width by height. The default includes the box and the content's bounds, grown by outsets. Override this when painting, clipping, or transforming content changes that area. The returned shape reserves paint space, not a clip. It also decides hit testing past the layout bounds: a press there reaches a child only where the paint bounds of a one-pixel content at the point cover the point.