From: Richard Wordingham (richard.wordingham@ntlworld.com)
Date: Mon Aug 22 2005 - 18:48:22 CDT
Philippe Verdy wrote:
> From: "Richard Wordingham"
>> Adam Twardoch wrote:
>>> GSUB tables don't handle the reordering in Indic languages. It's the
>>> responsibility of the OpenType Layout processor, e.g. Uniscribe.
>
> How can an OpenType Layout processor correctly reorder glyphs, when all it
> knows from a font is the binding of single (but whole) codepoints to
> glyphs, and this does not work for characters that have composite glyphs
> that must be reordered separately, and that don't have individual
> codepoints assigned to each part?
>
> To work reliably, it would mean that the fonts have to be specially marked
> so that the glyphs associated to each part are assigned predictable PUA
> codepoints where they can be found in the font's codepoint-to-glyph table.
Read the introduction to http://www.microsoft.com/typography/otspec/gsub.htm
. Remember that the non-PostScript part of the font definitions works
entirely in terms of glyph numbers; the relationship of glyph number to
character code is (with a very few - three?- exceptions) peculiar to each
font and is defined within it - the 'cmap' table.
Richard.
This archive was generated by hypermail 2.1.5 : Mon Aug 22 2005 - 18:49:34 CDT