Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!hplabs!hpl-opus!hpccc!hp-sde!hpcea!hpbsla!mfox
From: mfox@hpbsla.HP.COM (Martin_Fox)
Newsgroups: comp.lang.postscript
Subject: Re: Re: HPGL -> PostScript Converter wanted !
Message-ID: <500004@hpbsla.HP.COM>
Date: 3 Nov 88 19:35:39 GMT
References: <133@dx7.UUCP>
Organization: Hewlett-Packard Boise R & D Lab
Lines: 30


    Once again I was writing notes while eating lunch and stuck more than my
    sandwich in my mouth.

    I guess the word I focused on in the original note was "script".  I have
    noticed more than one request for HPGL <-> PostScript converters; some
    of them make it sound like a fairly simple chore, either way.  My note
    was a rather murky response to this.

    In the case of HPGL -> PostScript, I did not mean to imply that a
    PostScript program resident in the printer would need to interpret
    HPGL.  Somewhere along the line, however, the HPGL source would need
    to be parsed;  somewhere else along the line the modal information would
    need to be handled.  In the case of PostScript -> HPGL, however, the
    PostScript code would need to be interpreted to handle procedures, etc.
    Neither case is trivial.

    As for converting from any given 2-D graphical description system to
    PostScript;  remember that some systems use an OR-ing model for placing
    new images on the page (1 bits are written black, 0 bits are transparent).
    This can produce some effects that are difficult to achieve in PostScript,
    such as lines drawn with cross-hatches where only the hatch is drawn,
    allowing the underlying image to show through between the hatch marks.
    Between this and *fonts*, it can be more difficult than you think to
    map a given PDL to PostScript (particularly if you want the image 
    produced in less than an hour).

    Martin Fox
    HP Boise Division
    My Own Private Idaho