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From: odea@mars.jpl.nasa.gov (Andrew O'Dea)
Subject: Re: TrueType versus ATM
Message-ID: <1991Mar21.173231.7401@jato.jpl.nasa.gov>
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Reply-To: odea@mars.UUCP (Andrew O'Dea)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
References: <1991Mar20.164934.3177@waikato.ac.nz> <1991Mar20.080055.26542@neon.Stanford.EDU> <1991Mar20.220011.18395@comp.vuw.ac.nz>
Date: Thu, 21 Mar 91 17:32:31 GMT

In article <1991Mar20.220011.18395@comp.vuw.ac.nz> newbery@rata.vuw.ac.nz (Michael Newbery) writes:
>In article <1991Mar20.080055.26542@neon.Stanford.EDU> torrie@cs.stanford.edu (Evan Torrie) writes:
>>ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University) writes:
>>
>>>I've been doing some rough speed tests to see how TrueType compares with
>>>Adobe Type Manager 2.0.
>>
>>  So have I.  I've found one interesting thing.  Using Times, Truetype seems 
>>to be about 50% faster when rasterising the standard A-Za-z character set, 
>>but if you add in some of the special "option" characters, Truetype suddenly
>>starts rasterising noticeably slower than ATM.
>Not just Times, the others show the same behaviour. I played with some
>sample text I have which includes the entire Mac character set for a font
>and noticed that it flew along until it got to the 'special' characters.
>The slowdown only happens for characters with diacritics (a circumflex, e
>grave etc), not for other 'option' characters. Strangely enough it even
>seems to affect symbol for the characters in the same place as the
>diacritics, although this might just be because most such characters are
>'missing'.
>This is on a 5MB IIci with Micron cache card by the way.
>Given that the line layout manager is missing from 7.0, does anyone know
>if the Times, Courier or Helvetica fonts shipped have any interesting
>ligatures or swashes hidden away?
>
>--
>Michael Newbery<newbery@rata.vuw.ac.nz>
>"Homer knew that the first thing to do on getting your chariot out
>was to put the wheels on." John Chadwick--The Decipherment of Linear B

[theorizing on]
Maybe Truetype is only rasterizing the "normal" portion of the character set
initially.  Characters that aren't normally used get rasterized later.  That
might explain the speed difference between Truetype and ATM, as well.  Assuming
that ATM rasterizes the entire character set when it creates a bitmap.  Anyway,
that is my theory.
[theorizing off]

Andrew O'Dea, odea@kelvin.jpl.nasa.gov

