二维的画图类，可以进行点，线，三角形，矩形，椭圆，圆等形状的画图，并可进行缩放，是一个完整的类，直接调入自己的程序里面使用就可以的。-two-dimensional drawing class, for point, line, triangular, rectangular, oval, round shapes such as drawing, to carry out the zoom, is a complete category, transferred directly inside