在屏幕上绘制一个星星样图元，实现各种简单的图元变换操作，如错切，平移，旋转，对称，缩放。用键盘上下左右键操作，用TAB键切换变换形式。-Drawing on the screen of a star-like element to achieve a variety of simple primitives transform operation, such as shear, translation, rotation, symmetry, scaling. Up and down about