基于矩形窗口分区编码的圆形裁剪新算法

A New Algorithm for Circle Clipping Against Rectangular Window Based on Encoding Approach

裁剪是计算机图形学中基本问题之一,其核心问题是效率问题,而矩形窗口是常用的裁剪边界.在分析现有圆裁剪算法的基础上,提出了基于矩形窗口分区编码的圆裁剪算法,首先根据圆的八分对称性求出圆周的关键点,然后按规则进行编码,从而判断圆与矩形窗口的相交关系,并对圆进行相应的裁剪输出.实验结果表明,该算法减少了复杂运算的次数,避免了多余的无用计算,具有较高的运算效率.

Clipping is one of the basic issues of computer graphics.The most important character of clipping is the efficiency.Rectangular window is usually used as the clipping boundary.This paper proposed a new algorithm of circle clipping against rectangular window based on encoding approach.Firstly,eight key points are calculated by the symmetry of circle.Then,the intersection relationship between the circle and the rectangular window is judged according to the encoding regulation.At last,the clipping is executed and the retained part of circle is gained.The results show that the algorithm decreases the times of complicated computations and has the character of high efficiency.