| Allegro CL version 8.2 This page is new in 8.2. |
Arguments: point-x point-y box-left box-top box-right box-bottom &key margin
Returns as multiple values the coordinates of the point on the edge of
a box where it is crossed by a line that passes through the center of
the box and through an arbitrary
point. Returns nil
if the box center and the
arbitrary point are the same.
The first two arguments are real numbers for the X and Y coordinates
of the arbitrary point. The remaining required arguments are real
numbers that specify the sides of a box. Returns two real numbers for
the X and Y coordinates of the intersection point,
or nil
.
The margin argument is somewhat obscure. If specified, it should be a real number indicating a distance. If the real intersection point is less than this distance from a corner of the box, then the returned point will be adjusted so that it is this distance from the corner. (This is used by one application to avoid drawing a connecting line to a rounded corner of a rounded box.)
See also radial-line-box-intersection and radial-line-circle-intersection-x-y.
Copyright (c) 1998-2016, Franz Inc. Oakland, CA., USA. All rights reserved.
This page is new in the 8.2 release.
Created 2016.6.21.
| Allegro CL version 8.2 This page is new in 8.2. |