One anchor move as an undo step, walked by the drawing history or by the
host's timeline it was handed to (DrawingController.delegateInputAnchorSteps).
Each call writes the other side's point, and is false, writing nothing, once
the study no longer holds the point it starts from.
One anchor move as an undo step, walked by the drawing history or by the host's timeline it was handed to (
DrawingController.delegateInputAnchorSteps). Each call writes the other side's point, and is false, writing nothing, once the study no longer holds the point it starts from.