paintsChild method Null safety

  1. @override
bool paintsChild(
  1. covariant RenderBox child
)
override

Whether the given child would be painted if paint were called.

Some RenderObjects skip painting their children if they are configured to not produce any visible effects. For example, a RenderOffstage with its offstage property set to true, or a RenderOpacity with its opacity value set to zero.

In these cases, the parent may still supply a non-zero matrix in applyPaintTransform to inform callers about where it would paint the child if the child were painted at all. Alternatively, the parent may supply a zeroed out matrix if it would not otherwise be able to determine a valid matrix for the child and thus cannot meaningfully determine where the child would paint.

Implementation

@override
bool paintsChild(RenderBox child) {
  assert(child.parent == this);
  return _alpha > 0;
}