From: Peter_Constable@sil.org
Date: Thu Sep 26 2002 - 18:12:46 EDT
On 09/26/2002 02:54:55 PM "chuck clemens" wrote:
>It appears as I mentioned in email to
>Mark that Unicode fonts use block ranges. Can someone verify this?
The TrueType font format allows a vendor to indicate which "Unicode ranges"
a font supports. In Windows, there are APIs and data structures for making
this information available to an app. The only problem is that the notion
of "supports" is undefined: by what criteria does one decide whether a font
"supports" a given range? Only if every character in that range is
supported? Even if only one character in that range is supported? If >50%
of the characters are supported? If all the characters from that range
needed by some major language is supported? (If so, what major language,
and how does one decide exactly what characters a language "needs"? Does
English need the em dash? That depends upon one's purposes.)
For details on Unicode ranges in TrueType fonts, see
http://www.microsoft.com/typography/otspec/os2.htm#ur.
Note, BTW, that these are not used on the Mac (I don't know about other
platforms). Also, there's a real possibility that the number of Unicode
ranges that may eventually need to be supported by this mechanism in
TrueType fonts will exceed the number of ranges that the format can
accommodate (it's a bit vector of 128 bits, and 83 have been assigned
values to cover up to Unicode 3.0).
- Peter
---------------------------------------------------------------------------
Peter Constable
Non-Roman Script Initiative, SIL International
7500 W. Camp Wisdom Rd., Dallas, TX 75236, USA
Tel: +1 972 708 7485
E-mail: <peter_constable@sil.org>
This archive was generated by hypermail 2.1.5 : Thu Sep 26 2002 - 18:50:16 EDT