paint
Paints the laid-out tree in parent-before-child order.
An empty tree returns an empty read-only list. A non-empty tree must be laid out with no pending measurement or layout work. If that precondition fails, the tree is poisoned. A clean node reuses its complete local display list and combines it with current accumulated coordinates. Commands preserve local emission order. The core applies no implicit node or parent clipping. Valid local overflow outside those bounds is retained.
Return
an read-only list of retained commands with bounds in accumulated tree coordinates.
Throws
when layout is incomplete or geometry remains pending. It is also thrown when the operation is called from another execution owner, re-enters an active operation, or the tree is not active.
when a paint callback or scope operation throws after pipeline work begins and the exception escapes the callback. The original throwable is propagated unchanged after cleanup attempts.