曲线的整数型生成算法

AN ALL-INTEGER ARITHMETIC ALGORITHM FOR DRAWING CURVES

本文提出了一个用于光栅显示器或数字化绘图仪等显示设备中选择曲线上最佳点的通用算法．该算法由几部分组成，分别对应曲线的不同走向段．其最大的特点是可以根据实际曲线的走向，在算法的各部分实现自动跳动．由此算法可生成所有常用曲线．本文给出了Bezier曲线和B样条曲线的生成算法．这些算法选择距离实际曲线最近的网格点，并且只用整数运算．

This paper first describes a general algorithm for curve mesh point se-lection on incremental display devices such as a raster display or digital plotter.This algorithms is consists of several parts,and each part draws the segments of a curve which are in one range of direction. A key technique is used to make the algo-rithm skip properly from one part to the next part when the direction of the curve segment is changing. All the commonly used curves can be generated by this algo-rithm, and in this paper, algorithms for drawing Bezier curves and B-spline curves are presented. These algorithms select the closest mesh points to the true curves,and only integer calculations are required.