def add_keep_rect_within_constraint(canvas, parent, child):
solver = canvas.solver
child_nw = ItemProjection(child.handles()[NW].pos, child, parent)
child_se = ItemProjection(child.handles()[SE].pos, child, parent)
constraint = KeepRectangleWithinConstraint(parent.handles()[NW].pos, parent.handles()[SE].pos,
child_nw, child_se, child, lambda: parent.border_width)
solver.add_constraint(constraint)
parent.keep_rect_constraints[child] = constraint
def _keep_handle_in_parent_state(self, handle):
canvas = self.canvas
parent = canvas.get_parent(self)
solver = canvas.solver
if parent is None:
return
handle_pos = ItemProjection(handle.pos, self, self.parent)
constraint = KeepPointWithinConstraint(parent.handles()[NW].pos, parent.handles()[SE].pos,
handle_pos, lambda: parent.border_width)
solver.add_constraint(constraint)
self._waypoint_constraints.append(constraint)