线段及直线的基本运算 1. 点与线段的关系2. 求点到线段所在直线垂线的垂足3. 点到线段的最近点4. 点到线段所在直线的距离 5. 点到折线集的最近距离 6. 判断圆是否在多边形内7. 求矢量夹角余弦 8. 求线段之间的夹角9. 判断线段是否相交10.判断线段是否相交但不交在端点处11.求线段所在直线的方程 12.求直线的斜率 13.求直线的倾斜角14.求点关于某直线的对称点15.判断两条直线是否相交及求直线交点 16.判断线段是否相交，如果相交返回交点-straight line segment and a basic computing. Point and the line between the two. Seeking to point straight vertical line segment where the Pedal 3. Line points to the recent four points. Point to the straight line distance from the host 5. Set point to the recently broken away from six. To judge whether the circular polygon 7. for vector cosine angle 8. for the angle between the line 9. Line judge whether the intersection 10. Line judge whether the intersection but do not pay the endpoint Office 11. for the straight line segment where equation 12. for a linear slope 13. seeking straight tilt angle 14. Points on a linear symmetrical points 15. to judge whether the intersection of two straight and for 16 straight intersection. Line judge whether the intersection, the intersection to intersec