自己写的画板程序，有图片。可以画直线，矩形，圆形。如果需要多边形可以自行添加。我留了一个变量为多变形。-Sketchpad write their own programs, with pictures. You can draw a straight line, rectangle, circle. If you need to be able to add their own polygons. I left a variable for multiple deformation.