Path: utzoo!mnetor!uunet!mcvax!ukc!eagle!icdoc!qmc-cs!liam From: liam@cs.qmc.ac.uk (William Roberts) Newsgroups: comp.lang.postscript Subject: Re: psdraft Message-ID: <464@sequent.cs.qmc.ac.uk> Date: 6 May 88 19:44:16 GMT References: <8996@sol.ARPA> <9078@sol.ARPA> <840@zippy.eecs.umich.edu> <5847@well.UUCP> Reply-To: liam@cs.qmc.ac.uk (William Roberts) Organization: Computer Science Dept, Queen Mary College, University of London, UK. Lines: 49 Keywords: setgray, opaque ink Summary: PostScript colours are OPAQUE Sender: In article <5847@well.UUCP> samlb@well.UUCP (Samuel B. Bassett) writes: >I'd try 0.8 (0.7, 0.6...) setgray until the underlying text shows through >the draft, if I were in your shoes . . . Fun maybe - but you definitely won't make any profit with such a fundamentally incorrect understanding of PostScript! It won't work: PostScript "ink" is logically opaque, whatever the "colour" applied, so there will never be anything visible underneath. The problem of "how do I print the gray text at beginning of page" is easy and is solved in two stages: 1) Change "showpage" so that it becomes /showpage { showpage do_grey_text } bind def and thereby do your grey text immediately at the beginning of all pages except the very first (NB: do_grey_text is probably not the actual routine name...) 2) Notice that the psdraft stuff is being inserted before the any of the actual printing commands in the PostScript document, so just print the grey text directly at the end of the PostScript code inserted by psdraft Note for purists: the second step actually causes printing within the Prologue and so breaks the document structuring conventions. To do this properly would involve adding the do_grey_text (or whatever) immediately after the first %%Page comment The only approved way of laying down black dots in some kind of stipple pattern without filling the white around them is to use the "imagemask" primitive and a stipple bit pattern. This is like "image" applied to a 1 bit-per-pixel raster, except that only the "black" pixels are painted. The clipping region applies, so you can clip to the outline of the text, but you will have to do your own tesselation. The unapproved way (used extensively by the Macintosh) is to change the halftone screen using "setscreen", but this isn't properly portable between printers as it depends on the printer pixel size etc. -- William Roberts ARPA: liam@cs.qmc.ac.uk (gw: cs.ucl.edu) Queen Mary College UUCP: liam@qmc-cs.UUCP LONDON, UK Tel: 01-975 5250