摘要
影线填充是一种重要的计算机绘图方式,它要求用影线能对任意形状的有界区域进行填充。D-SCAN 绘图系统中的 SHADE(阴影)子程序和 GKS 系统中的 GFA(区域填充)子程序具有类似的功能。但它们都对作图有一定的限制,无法满足用户多样化的需求。作者应用坐标变换原理求解影线与区域边界的交点,并从集合论的角度出发,提出了一种消除交点与边界顶点重合情形的方法。由此编制的程序、计算方法和判断过程都十分简单,计算速度比一般方法大为提高。这种方法不仅能用于单连通区域的填充,而且可用于多连通区域的填充。
Filling(bounded)region with shade lines is one important type ofcomputer plots.The SHADE routine of D-SCAN system and GFA routine ofGKS system possess this function.However,they have a few limitations forplotting so that they can not satisfy some needs of users.In this paper,a methodto find the node coordinate where the shade line intersects the region boundary ispresented by means of coordinate transformation.We remove the superpositionbetween the node and the apex of the region boundary by using the set theory.Thus,the algorithm and logical relation in our program are very simple.It can beused for filling simply or multiply connected regions.
出处
《计算机应用与软件》
CSCD
1993年第4期49-53,F003,共6页
Computer Applications and Software
关键词
计算机绘图
影线填充
坐标变换
Region
simply connected region
polygon
shade lines
coordinatc transformation
set theory
