box-intersect

Arguments: box1 box2 &optional box-to-return

Returns the box which is the intersection of the arguments, or nil if they do not intersect. If box-to-return is specified and non-nil, it must be a box object (see make-box). If that case, box-to-return will be modified to be the intersection, if box-intersect returns non-nil. (This will save space by avoiding the creation of a new box object.) If box-to-return is unspecified or specified nil, a new box is created if the arguments intersect.

Boxes which touch just on their edges or at the vertices are not considered to intersect. Thus,

(make-box 10 10 20 20)

does not intersect

(make-box 20 20 30 30)

but does intersect

(make-box 19 19 30 30)

See the description of the box class for general information on boxes.

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This page was not revised from the 8.1 page.
Created 2010.1.21.