初学者可往下看本例程的原理：

1、依次获得取样点的颜色

2、在取样点画该颜色的方框



取样越精，方框越小，图像就越清晰 -Beginners can look down the principles of this routine: 1, followed by access to the color of sampling points 2, stipple the colors in the sampling of the more refined sampling box, the smaller the box, the image will be clear