Re: Possible Pango 1.4 ideas

[Owen Taylor <otaylor redhat com>]

Noah Levitt <nlevitt columbia edu> writes:

> Hello,
> 
> I have another feature request, hopefully also just a
> doddleô smarter rendering of so-called invalid combinations.
> 
> OpenType documentation[1] seems to say that invalid
> combinations should be handled thusly:
> 
>  - If a combining character is preceded by a space and a
>    zero width joiner, render it all by itself.
> 
>  - Otherwise, render it on top of U+25CC DOTTED CIRCLE.
>    This way it will look the way it does in the unicode.org
>    code charts.
>    
> Note also that the Unicode Standard 3.2, section 2.6, says:
> "By convention, diacritical marks used by the Unicode
> Standard may be exhibited in (apparent) isolation by
> applying them to U+0020 SPACE or to U+00A0 NO BREAK SPACE."

Feature requests are best put into bugzilla.gnome.org; not that it
means that that they'll necessarily be acted upon unless someone shows
up who wants to work on them; but at least they can be tracked
reliably that way.

Rewriting the combining mark handling in basic-xft would be a
rewarding and useful piece of work. It needs to use OpenType features
when present and make reasonable fallback guesses when they
aren't. The first is way easier than the second.

(I think the hebrew-xft shaper is a bit more sophisticated than
basic-xft in it's non-OpenType handling of combining marks, so it's
worth looking at that.)

Regards,
                                        Owen