一个二维裁剪算法-用梁友栋－barsky算法实现直线段相对于给定窗口的裁剪-A two-dimensional cutting algorithm- with Liangyou Dong-barsky algorithm relative to a given straight line cut the window

在MFC下实现梁友栋的二维裁剪算法，二维图形是固定矩形。-to realize Barsky algorithm in MFC.