Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!udel!rochester!kodak!ispd-newsserver!ism.isc.com!ico!rcd From: rcd@ico.isc.com (Dick Dunn) Newsgroups: comp.lang.postscript Subject: Re: mirror image Summary: a couple of problems Message-ID: <1991Apr11.185251.1450@ico.isc.com> Date: 11 Apr 91 18:52:51 GMT References: <14828@mcdphx.phx.mcd.mot.com> <11404@exodus.Eng.Sun.COM> Organization: Interactive Systems Corporation, Boulder, CO Lines: 36 rberlin@birdlandEng.Sun.COM (Rich Berlin) suggests the following, in the course of trying to get rid of page width hard-wired into a piece of PostScript from an earlier article: > ...The PostScript interpreter can > ALWAYS tell your program the size of the page. Add the following > procedure to your bag of tricks: > > /printable-area { % - => llx lly urx ury > gsave clippath pathbbox grestore > } bind def The procedure gives just what it says--the printable area. This is seldom the same as the page size, because most printers have to provide a "margin" so they won't try to dump toner off the edges of the paper. (It also reduces the memory for the page bitmap a little.) A reasonable guess is that the margins on the printable area will be symmetric, so adding llx to urx should give the page width. (No guarantee there, of course; it's just a good guess. x symmetry is more likely than y.) Also...Rich suggests mirror-imaging as follows: > printable-area % stack: llx lly urx ury > 0 exch % llx lly urx 0 ury > translate % llx lly urx > pop pop pop % - > -1 1 scale Aside from the margin problem, this looks to me as if it translates up to the top of the page (using 0 ury) as if to prepare for a vertical reflec- tion, then does -1 1 scale, which is a horizontal reflection and will throw the image off the page above and to the left. -- Dick Dunn rcd@ico.isc.com -or- ico!rcd Boulder, CO (303)449-2870 ...Lately it occurs to me what a long, strange trip it's been.