一种有效的圆形窗口线裁剪算法

根据线段两端点相对于圆形窗口的可能位置讨论裁剪结果。当两端点都在圆形窗口之外时，通过圆切线斜率与线段斜率的比较，及点区域判别来判断线段与窗口的相交情况。在确定线段与圆形窗口有交点的情况下，应用参数化形式求交运算，简化求交方程的构造。实验结果表明，新算法显著提高了裁剪效率。

An Efficient Line Clipping Algorithm Against Circular Window

The result of clipping is discussed according to possible positions for both endpoints of a line segment in relation to circular window. The intersection is determined by comparing the slope of the tangent with the slope of the line segment and the ingenious region detection about the point when both endpoints of the line segment are outside of the circular window. Simplify the intersection equation by means of the intersection calculation with the parametric form when the intersection actually happens. The experimental results show that the new algorithm further improves the clipping efficiency.