咱们初步检验测验旋转一个矩形: 先画一个矩形: mg_line testline = new mg_line(new PointF(400, 400), new PointF(400, 500)); mg_line testline1 = new mg_line(new PointF(400, 500), new PointF(600, 500)); mg_line testline2 = new mg_line(new PointF(600, 500), n...