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Setting Bounding Box in lispm postscript

    Date: Mon,  5 Mar 90 18:04:57 EDT
    From: "Bruce R. Miller" <MILLER@vax.cam.nist.gov>

	Date: Sat, 3 Mar 90 00:33 EST
	From: Chris Lindblad <cjl@ai.mit.edu>

	    [...]

	This is all correct, but here at the AI lab Jerry Roylance has come up with a
	tex macro that will reads the bounding box information in the the header of a
	postscript file, and then automatically computes up with the right offsets for
	the psfile special so that the lower left of the bounding box appears at the
	(tex) point.  It also makes a (tex) box the exact size of the bounding box, so
	the macro semantically is the same as setting a character of the size of the
	bounding box.  See the comments in this file for more information:

	% -*- Mode: TeX -*-

	% Merging PostScript Illustrations

	[...]

	% The header looks like
	%
	%    %!PS-Adobe-1.0
	%    %%Creator: Illustrate Version 11.0
	%    %%CreationDate: 6/23/87 17:35:01
	%    %%Pages: 1
	%    %%BoundingBox: 466.12912 718.63934 612.0283 792.0283
	%    %%EndComments
	%
	% *** Should complain if #2 is (atend)

	[...]

    Very nice macro!
    The only thing I could want would be a sort of 
       \psadobe[desired_width][desired_height]{psfile}
    which would set up the scaling the image up to the desired dimensions.
    (complain, complain)  Shouldn't be too hard given the tools Jerry has
    given, though...

    As you know, the standard lispm  postscript output does not include  the
    bounding box; without making two passes, its got no way of knowing.

    I've written a  presentation based  lispm graphics  program that  allows
    drawing in arbitrary user coordinates. It also builds its own record  of
    what's being drawn; allowing you to `edit' the image, which updates  the
    record. The record is used to  redraw the image as needed,  to determine
    the `allowable' operations on an image fragment, etc.

    It also uses  this record  to `redraw'  the whole  thing onto a hardcopy
    stream when hardcopy is  requested.    This keeps  it close to  whizywig
    while still letting postscript do  its best.    Since when  hardcopying,
    the image is  also already  on the  screen, I  have a  cheep shortcut to
    determine  the  (approximate)   bounding  box;   extract  it   from  the
    presentations dw:bounding-box'es.    I did  this primarily to  translate
    the postscript  output  so  that  its  lower-left  corner was at 0,0, to
    simplify using psfile, as  I described in  an earlier message.   It also
    tells me the width & height, but I've got to make note of it to manually
    insert the approp.  \vspace etc into the TeX document.

    I  should  be  able  to  automatically  use  this  info  to  generate  a
    %%bounding box in the ps output.  But, it seems that I have to  redefine
    (or shadow)

	    (flavor:method :send-header-comments postscript-output-stream)

    and either define additional optional/keyword args (and thus modify 
    :send-page-buffers, and who knows what else), or special-vars, or ...

    Has anybody  done  such  a  thing,  or  have  suggestions as to what the
    cleanest way (ie least problems later) of doing this are? (or know if
    this can be done cleanly in 8.0?)

In 8.0, the postscript-output-stream flavor has settable instance variable
eps-bounding-box that when non-nil is put in the header comments like this:

    (when eps-bounding-box
      (lexpr-funcall #'format output-stream
		     "~&%%BoundingBox: ~D ~D ~D ~D~%" eps-bounding-box))

So what you would do is have your code send a :set-eps-bounding-box to the
hardcopy stream and a bounding box comment appears in the header.  To patch
your 7.2 to make it like release 8.,0, add a gettable and settable inst var
eps-bounding-box, initially nil to the postscript-output-stream flavor.  Then
add the above code to the :send-header-comments method.
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