Path: utzoo!attcan!uunet!midway!ncar!asuvax!cs.utexas.edu!usc!zaphod.mps.ohio-state.edu!rpi!leah!cook!karp!karp.albany.edu!rennie From: rennie@cs.albany.edu (William A Rennie) Newsgroups: comp.graphics Subject: Re: solution: pixel aspect ratio in GIF images Message-ID: Date: 16 Jul 90 21:36:32 GMT References: <9866@pt.cs.cmu.edu> <9894@pt.cs.cmu.edu> <12198@mentor.cc.purdue.edu> Sender: rennie@karp.albany.edu Followup-To: comp.graphics Organization: Computer Science Department, SUNY at Albany, Albany, NY 12222 Lines: 18 In-reply-to: ahg@mentor.cc.purdue.edu's message of 16 Jul 90 19:13:06 GMT In article <12198@mentor.cc.purdue.edu> ahg@mentor.cc.purdue.edu (Allen Braunsdorf) writes: >It seems to me that a workable solution for GIF files would be to >standardize on Brian's suggestion: let the screen dimensions in the >file header represent a pixel area that fills a 4x3 physical area. >A GIF reader could then rescale the image appropriately for its own >screen. > The GIF standard written by Compuserve has hooks available for expansion. Even better, the standard assumes that all existing viewers will ignore the expansion information. (As I recall they have a header code that is supposed to mean ignore me to current viewers.) The pixel aspect ratio problem is a major one. Perhaps pressure on Compuserve would force a usable expansion. Bill Rennie rennie@cssun.albany.edu