Bounding boxes

To properly translate and scale a figure psfig must know its `natural' position on the page; this information is present in what is called the bounding box of a PostScript program. The bounding box is an outer limit to the marks created by a program, and is specified as four coordinates of a rectangle: the lower-left x coordinate (bbllx), the lower-left y coordinate (bblly), the upper-right x coordinate (bburx), and the upper-right y coordinate (bbury). Adobe has defined a convention whereby the bounding box of a program is contained in a `bounding box comment'. ²This comment, which must be present in any file to be used as a psfig figure, is a line of the form

%%BoundingBox: bbllx bblly bburx bbury

All values are in PostScript points, relative to the default transformation matrix. The only mandatory PostScript convention is that the first line of the file should begin with the characters `%!' (a `%' begins a comment in PostScript.) A good place for the bounding box comment is as the second line of the file.

If a bounding box comment is present in the figure file, psfig will extract its values. The bounding box values may instead be specified directly in the \psfig argument, using clauses of the form bbllx=bbllx,bblly=bblly,..., in which case the figure file is not searched for the bounding box.