Path: utzoo!attcan!uunet!bu.edu!snorkelwacker!tut.cis.ohio-state.edu!pt.cs.cmu.edu!zog.cs.cmu.edu!tgl From: tgl@zog.cs.cmu.edu (Tom Lane) Newsgroups: comp.graphics Subject: Assumed pixel aspect ratio in GIF images? Message-ID: <9866@pt.cs.cmu.edu> Date: 11 Jul 90 15:23:25 GMT Organization: Carnegie-Mellon University, CS/RI Lines: 19 I've been looking at some of the GIF image archives here and there on the net. I find that some of the images look just fine on my workstation, while others are visibly distorted: usually, compressed vertically by 20% or so. I presume that such images have been set up to look OK on IBM-PC EGA and similar displays, which have non-square pixels. However, the extent of the distortion seems to vary between files; maybe there are different pixel aspect ratios in common use? The GIF documentation that I have makes no mention of the question of pixel shape. Is there any recognized convention about whether a GIF image is set up for square or non-square pixels, and what the assumed pixel aspect ratio is in the latter case? -- tom lane Internet: tgl@cs.cmu.edu UUCP: !cs.cmu.edu!tgl BITNET: tgl%cs.cmu.edu@cmuccvma CompuServe: >internet:tgl@cs.cmu.edu