从堆栈中取出坐标，绘制一个绿色矩形，以便删除之前的转换和缩放。
Pop the stack and draw a green rectangle to remove the previous translation and scaling.
前一个任务只需记住最后绘制的矩形(和颜色)，而后者要求全都记住。
The former task requires remembering only the last rectangle drawn (and the color), while the latter requires remembering them all.
这里绘制了一个矩形、一个透明的圆和一个三角形。
Here a simple square is drawn, with a transparent circle and triangle.
应用推荐