Re: Thai rendering regression after harfbuzz-ng

[Theppitak Karoonboonyanan <thep linux thai net>]

On Sat, Sep 19, 2009 at 9:44 PM, Theppitak Karoonboonyanan
<thep linux thai net> wrote:
> On Sat, Sep 19, 2009 at 9:33 PM, Behdad Esfahbod <behdad behdad org> wrote:
>
>> In the mean time, you can compile pango with CPPFLAGS=-DHB_DEBUG=100 and
>> check the log to see what's going on.
>
> OK. Thanks.

I can't find what the problem really is yet. But please see
the last clue I got in comment #9 in the bug:

  https://bugzilla.gnome.org/show_bug.cgi?id=595539#c9

I've tried debugging further by inserting fprintf() here and there,
but I can't really grab HB mechanism yet.

The code points passed to match_{backtrack,input,lookahead}()
are not Unicode, but some 8-bit codes, but the glyph classes
can be evaluated from that.

And in a rule that should match input glyph with class 2 as
the final item appears to match with class 0 instead. If I prevent
class 0 from being matched at all, it works! But this is too
hacky, though.

Regards,
-- 
Theppitak Karoonboonyanan
http://linux.thai.net/~thep/