update method

@override void update(double dt)

Update edge display by data of edge. 根据节点数据，对界面进行更新

Implementation

@override
void update(double dt) {
  super.update(dt);
  position = edge.start.cpn!.position;
  size = edgeShape.size(edge);
  angle = edgeShape.angle(edge);
  edgeShape.setPaint(edge);
}