Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!usc!snorkelwacker.mit.edu!ai-lab!life!sbchanin From: sbchanin@ai.mit.edu (Steve Chanin) Newsgroups: comp.lang.postscript Subject: What does concat do? Message-ID: Date: 19 Dec 90 16:56:48 GMT Sender: news@ai.mit.edu Reply-To: sbchanin@ai.mit.edu Organization: MIT Artificial Intelligence Lab Lines: 49 Postscript Wizards, I've got some code which draws pictures composed only of lines in a mac window under mac allegro common lisp. I wanted to be able to edit it in a graphics program, so I wrote a few functions to dump postscript in the format used by idraw (a macpaint clone which runs under x and uses postscript as its save format). A line drawn with idraw and saved as a .ps file looks like: Begin %I Line %I b 65535 1 0 0 [] 0 SetB %I cfg Black 0 0 0 SetCFg %I cbg White 1 1 1 SetCBg %I p 0 SetP %I t [ 1 0 0 1 97 183 ] concat %I 44 441 260 325 Line End Most of the commands are defined in the idraw prolog (at the end of this message I've included a complete idraw file for a picture containing two lines in case you need to see this prolog to understand the preceeding postscript), but the key line seems to be: 44 441 260 325 Line As far as I can tell, if I map each line in my mac window into a paragraph like the one above except with the 4 numbers before Line changed, everything works fine (i.e. I get a postscript file which I can view and print). However, the question I have is what does the concat command do? What do the 6 numbers mean? Different lines in idraw seem to have a different matrix preceeding the concat command, but I'm not sure what those matrices do or how to generate the correct values for them. In some sense, since it works, maybe I shouldn't fix it, but I'd like to make the code available to other people and before I do that, I'd like to make sure that it's "right." I'd appreciate any help that anyone can give me. Also, please make your explanations simple because I don't know anything about postscript (in fact before yesterday when I decided I needed to dump postscript, I'd never even seen a postscript program). Thanks alot, Steve -- =============================================================================== DOMAIN: sbchanin@ai.mit.edu MIT Artificial Intelligence Lab USMAIL: Steven Chanin, 545 Technology Square Rm. 827, Cambridge Ma 02139 PHONE : (617) 253-8963