Re: Fwd: Malayalam & SF_PROCESS_ZWJ

[Eric Mader <emader icu-project org>]

Just to be clear, the SF_PROCESS_ZWJ says that the ZWJ/ZWNJ glyphs 
should be passed to GSUB processing. For most Indian scripts, it's 
sufficient to see the ZWJ/ZWNJ characters during character processing 
where they are used to assign the correct features to the surrounding 
characters. I think it should be possible to do everything needed for 
the Malayalam script without passing the ZWJ/ZWNJ characters to GSUB. 
(Though I haven't looked into the particular bug being discussed ;-)

Talk of developing our own standards makes me very nervous. I think it's 
important that we implement the same standard as Windows. 
Interoperability must be our most important goal. Otherwise chaos will 
result. The thing I hear most often from clients submitting bugs against 
the ICU LayoutEngine is "but it works on Windows..."

Users expect things to work the same way on every platform, and they should.

Regards,
Eric Mader
IBM GCoC - ICU Team

Praveen A wrote:
> 2007/6/19, Harshula <harshula gmail com>:
> > > The Rachana_w01 does not use ZWJ in the GSUB table(for chillus,ie).So
> > > to avoid  unnecessary rendering of ZWJ the SF_PROCESS_ZWJ flag has to
> > > be removed.Otherwise, include the ZWJ reference in the GSUB of the
> > > font and use the SF_PROCESS_ZWJ flag.My patch uses the latter option.
> > >
> > > suresh
> > Isn't Suresh indicating that he is using ZWJ in GSUB, thus requiring the
> > process ZWJ flag?
>
> Again it is dependent on font, it seems, we have to have a standard -
> we will work out one. So will revert back after some more testing with
> different fonts.
>
> Cheers
> Praveen