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From: ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University)
Newsgroups: comp.sys.mac.system
Subject: Re: TrueType versus ATM
Message-ID: <1991Mar21.161132.3195@waikato.ac.nz>
Date: 21 Mar 91 16:11:32 +1300
References: <1991Mar20.164934.3177@waikato.ac.nz> <1991Mar20.080055.26542@neon.Stanford.EDU> <1991Mar20.193744.10870@m.cs.uiuc.edu>
Organization: University of Waikato, Hamilton, New Zealand
Lines: 46

In article <1991Mar20.193744.10870@m.cs.uiuc.edu>, gillies@m.cs.uiuc.edu
(Don Gillies) brings up a couple of objections to my comparative speed
tests of TrueType versus ATM:

 "(1) Adobe's algorithm may indeed produce better 300dpi or
      180dpi results.  This is because adobe's font hints
      are just data structures, and the algorithm that makes
      use of these data structures is still proprietary and is
      still rumored to do a superior job of rasterizing fonts.
      Superior 180dpi and/or 300dpi results are probably what you
      want in the long for a quickdraw printer driver."

It's true that Adobe's hinting scheme may have started out as
a pure data-driven design, with the actual hinting algorithms
hidden in the PostScript implementation. But it's no longer so
pure. Current versions of Adobe fonts do indeed contain procedural
PostScript code to implement some of the hinting--see Appendix 3
of the "Adobe Type 1 Font Format" book, version 1.1.
   Moral: a high-level, data-only hinting scheme may not be as
wonderful as you might think.
   As for the quality of Adobe's fonts and hinting versus that of
the TrueType font designers, I'll leave that to others to argue about
--for now.

 "(2) If ATM 2.0 does indeed use type-1 'hinting' to produce
      these improved fonts, then two different fonts may have
      completely different amounts of hinting, not to mention
      different amounts of total fill, and serifs, etc.  In my
      opinion, only similiar fonts (times - times, helvetica -
      helvetica, etc) can be compared in a meaningful way."

I'll concede that, in principle, you have a point. Something like
this did indeed cross my mind. However, since my timings were
consistent across different fonts--to within the accuracy that I
could measure--I'm inclined to believe that, for these common
fonts (corresponding to the ones built into current LaserWriters),
the difference is insignificant.

But I'm ready to be proved wrong. Enough talk--let's have some more
tests!

Lawrence D'Oliveiro                       fone: +64-71-562-889
Computer Services Dept                     fax: +64-71-384-066
University of Waikato            electric mail: ldo@waikato.ac.nz
Hamilton, New Zealand    37^ 47' 26" S, 175^ 19' 7" E, GMT+12:00
When you've been swimming in C for too long, you get brine-damaged.