Traditional scan-linePolygon-Filling Algorithm can only deal with horizontal scan-lines and can only fill a polygonline by line.
传统的扫描线多边形填充算法只适用于水平扫描线的逐行填充。
2
If the horizontal line drawn is aligned with a polygon vertex, then only the segments that are below the line are counted.
如果所绘制的水平线与一个多边形顶点对齐，那么只计算位于该线下方的部分。
3
Recall from Section 1 of compositePieIndicators.pl that the location of the text is defined as the first set of polygon coordinates on a line from the triangle.vertices file.