圆形窗口裁剪算法的研究与实践

本文在对图形开窗-裁剪算法深入研究的基础上,提出了两种新颖而又实用的圆形窗口“裁剪”算法.算法(1)以图形坐标变换及采用正、负区域法原理为判别手段,使直线与窗口快速求交,程序设计简单易行。算法(2)用直线与圆形窗口交点处的t作参数,推导出简单易行的数学判别模式,经判别后,确定是否可求出参数t及其对应的交点坐标。

Clipping Algorithm and Practice of Circular Window

This paper gives two simple and practical new clipping algorithms of circular window, based on the study of graphic window and clipping method.Based on the principle of analytic geometry, algorithm (1) uses two judgements: one plane is divided into two parts by a straight line, and figure coordinate conversion. The principle of midpoint redivide makes the program run simply.Algorithm (2) gives an equation, by using t as a parameter about a crossing point between the straight line and window, and calculating crossing point coordinate at last. Taking t value as a judgement we put t into straight line parameter equation, and then can get the coordinate value about the crossing point.