From: Richard Wordingham (richard.wordingham@ntlworld.com)
Date: Mon Mar 20 2006 - 15:31:33 CST
Peter Constable wrote:
> Here's what's happening: Charmap is reading the cmap table for AUMS to
> determine what characters to display in its palette. But then it proceeds
> to call a text-drawing API in a standard way that would be needed to draw
> running text in each script rather than an alternate way that avoids font
> fallback and ensures that each character from the font is displayed. The
> standard call passes through Uniscribe which then determines for each
> script whether OpenType Layout support is required. Of course, for all of
> the Indic scripts, this is required. Uniscribe then checks which scripts
> the font has OpenType Layout tables for: AUMS has OpenType Layout tables
> for Devanagari, Gujarati, Gurmukhi, Tamil and Kannada, but not for
> Bengali, Oriya, Telugu or Malayalam. Since running text will not display
> correctly for the latter four scripts without OpenType layout tables,
> Uniscribe selects fallback fonts for these. For Bengali, Telugu and
> Malayalam, which are supported in XP SP2, it falls back!
Does this mean that unsupported scripts that might benefit from OpenType
Layout should have (unusable - untestable?) OTL tables in a font if the font
is to be usable? Might this explain why all the Lao-centred fonts I have
are reluctant to render Lao? Code2000 is one of the very few fonts to
render Lao in Notepad. Does Lao genuinely need OTL? I can see how it can
benefit from it, but that is not the same statement.
Richard.
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