bug#5081: zwj should not be ignored in indic text

[Praveen A]

2009/12/1 Kenichi Handa <handa@m17n.org>:
>> ZWJ is required to display some characters (like Malayalam chillu or
>> pure consonants) in many indic languages (Persian and Arabic also
>> needs these characters). These should not be ignored while displaying
>> indic text.
>
> Please try to evaluate this:
>
> (let ((script-regexp-alist
>       `((devanagari . "[\x900-\x97F\x200C\x200D]+")
>         (bengali . "[\x980-\x9FF\x200C\x200D]+")
>         (gurmukhi . "[\xA00-\xA7F\x200C\x200D]+")
>         (gujarati . "[\xA80-\xAFF\x200C\x200D]+")
>         (oriya . "[\xB00-\xB7F\x200C\x200D]+")
>         (tamil . "[\xB80-\xBFF\x200C\x200D]+")
>         (telugu . "[\xC00-\xC7F\x200C\x200D]+")
>         (kannada . "[\xC80-\xCFF\x200C\x200D]+")
>         (malayalam . "[\xD00-\xD7F\x200C\x200D]+"))))
>  (map-char-table
>   #'(lambda (key val)
>       (let ((slot (assq val script-regexp-alist)))
>         (if slot
>             (set-char-table-range
>              composition-function-table key
>              (list (vector (cdr slot) 0 'font-shape-gstring))))))
>   char-script-table))

Now it is displayed as a separate glyph, but there is no substitution
happening. ണ + ് + ZWJ should be displayed as one glyph (gpos
substitution).


> If it still doesn't work, please tell me the version numbers
> of libotf and libm17n-flt, and also tell me which font is selected
> for Malayalam.

It started working after I changed the default font to Rachana. It
also worked with Meera, but there is another problem when using Meera
https://savannah.nongnu.org/bugs/?28129  ttf-freefont is coming as a
default. I confirmed the need for above code by setting Rachana as
default font without the above code and I can confirm, the above code
is required to display zwj.

>
> % pkg-config --modversion libotf
> % pkg-config --modversion m17n-flt

libotf 0.9.10
m17n-flt 1.5.4

- Praveen

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emacs-zwj-after.png
Description: PNG image

zwj-with-rachana.png
Description: PNG image