Re: Fwd: Malayalam & SF_PROCESS_ZWJ

["Sayamindu Dasgupta" <sayamindu gmail com>]

Hi all,

On 6/19/07, Eric Mader <emader icu-project org> wrote:
> 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 ;-)

I don't know how to read Malayalam, but I don't see anything in the
section on Malayalam in the Unicode documents (5.0) which would make
SF_PROCESS_ZWJ a requirement for Malayalam rendering.

> 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.

I agree entirely. What has been a dire necessity for a long time is a
set of well defined test cases for all the Indic scripts that contains
all the known corner cases and special cases (chillu in Malayalam,
ra-japhala in Bengali, etc) and which can be tested against various
rendering systems (Pango/QT/ICU/Uniscribe) to ensure that things show
up in the same manner no matter what the underlying mechanism and/or
platform is.

To begin with the efforts, we (the Bengali team) have been using a
very rudimentary test case of our own
(http://www.stat.wisc.edu/~deepayan/Bengali/FreeBangTemplate/juktolist.txt)
for testing the fonts that we have developed. It is based on a list of
possible conjuncts (taken from a spelling dictionary commonly used for
our language) and also based on the experience we have gathered while
working on Bengali and FLOSS for the past five years. If such a list
can be compiled for the other scripts as well, we may have the
beginning of a Indic test suite that has been discussed in various
forums/workshops/conferences/mailing lists for the past four years (at
least)

Warm regards (and sorry for the semi off topic rant)
Sayamindu


--
Sayamindu Dasgupta
[http://sayamindu.randomink.org/ramblings]