Path: utzoo!attcan!uunet!intercon!news From: amanda@mermaid.intercon.com (Amanda Walker) Newsgroups: comp.fonts Subject: Re: PostScript vs TrueType? Message-ID: <26BED8B2.F2B@intercon.com> Date: 7 Aug 90 15:05:21 GMT References: <1100.26af57d3@waikato.ac.nz> <1990Jul26.135834.9874@tsa.co.uk> <862@grenada.UUCP> <9583@goofy.Apple.COM> <3880@bwdls58.UUCP> <237@heaven.woodside.ca.us> Sender: usenet@intercon.com (USENET The Magnificent) Reply-To: amanda@mermaid.intercon.com (Amanda Walker) Organization: InterCon Systems Corporation, Herndon, VA Lines: 26 Both Adobe and TrueType fonts have a certain amount of support for taking marking engine characteristics into account. In TrueType, this is done by having a set of three "compensation terms" that affect four different classes of distance ("gray", "black", and "white"), which affect how the rounding works. Of course, like most things in TrueType, this rounding (and which compensation term to use) must be explicitly programmed into the code for each glyph. Adobe implementations of Type 1 interpreters use the "erosion" technique mentioned by Glenn to adjust outlines depending on printer characteristics. From what I can tell, the erosion code affects how stem hints are applied, so that stems get thickened up on write-white engines and thinned down on write-black engines. It works pretty well; I first got curious about Type 1 fonts when I noticed that they didn't come out anorexic on a Toshiba marking engine (the Dataproducts LZR-2665), and Type 3 fonts did... The LanguageGroup hint (and the older RoundStemUp hint) evidently affect whether or not erosion is applied (since it might not be as good of a heuristic for non-Roman characters). -- Amanda Walker InterCon Systems Corporation -- "What a strange pattern the shuttle of life can weave." --Frances Marion