HELP LINE_INTERSECTION                              David Young
                                                    February 1997

LIB * LINE_INTERSECTION computes the intersection point of two lines on
a plane. The lines are specified using the coordinates of two points on
each.

line_intersection(__a1, __a2,  __b1, __b2,  __c1, __c2,  __d1, __d2) -> (__s1, __s2)
        The points (__a1, __a2) and (__b1, __b2) lie on one line; the points
        (__c1, __c2) and (__d1, __d2) lie on the other. The point (__s1, __s2) will
        lie on the intersection. (Here __a1 and __a2 are the Cartesian
        coordinates of the point _a.) If the lines are parallel __s1 and __s2
        will be <false>.

        The intersection point _s might lie on the line segments _a to _b
        and _c to _d, but it might not. Examples:


                 _a                       _c|
                |                         |
                |                         +_s
        _c       |_s      _d                 |
        --------+--------                 | \ _a
                |                         |  \
                |_b                        |   \
                                         _d|    \ _b



                        \_a
                         \
                          \_b

               _c--------_d   +_s


--- _________________________________$popvision/help/line_intersection
--- _________Copyright __________University __of ______Sussex _____1997. ___All ______rights _________reserved.