This function is only intended to be used when implementing new canvas items, specifically container items such as CanvasGroup.
It paints the item and all children if they intersect the given bounds.
Note that the scale argument may be different to the current scale in the
CanvasItem, e.g. when the canvas is being printed.
| this |
a CanvasItem. |
| cr |
a cairo context. |
| bounds |
the bounds that need to be repainted, in device space. |
| scale |
the scale to use to determine whether an item should be painted. See visibility_threshold. |