Abstract: The development and present situation of drawing circle algorithm are introduced，and to point out the faults by empirical analysis and summarizing for Bresenham’s algorithm and Kuzmin’s algorithm.Then，a new algorithm chooses the best approximate pixels to the circle with only integer arithmetic，based on the double-step circle drawing algorithm of Wu and Rokne.Finally，the new drawing circle’s algorithm with different grey scales is proposed.It generates 3 intermediate shades of grey scale than the double-step algorithm by Wu and Rokne，and the greatest error of intensity is reduced 1/4.These algorithms are easy to be performed by hardware.

Key words: circle arc, double-step algorithm, integer arithmetic, pixel gray-scale, anti-aliasing

摘要： 首先介绍了圆生成算法的发展及现状，接着对绘制圆的Bresenham算法及Kuzmin单点生成算法进行了实验分析及总结，并指出了其存在的优缺点。基于Wu和Rokne双步圆算法提出了新的双步反走样生成算法，使其成为一种反走样效果更佳的方法。该算法的灰度级数是原来Wu和Rokne算法的3倍，且最大灰度误差也比原来的减少了1/4；另外该算法由于只用整数运算，避免了除法，因此便于硬件实现。

关键词: 圆弧, 双步算法, 整数运算, 像素灰度, 反走样