[HarfBuzz] [PATCH] Added an Indic shaper

[Behdad Esfahbod]

On 04/21/11 11:12, suzuki toshiya wrote:
> 
> I guess the usage of "init" for script support is for the
> script that the presentation forms of a character can be
> classified into 4 types: initial/medial/final/isolated,
> aslike Arabic. The classification of the presentation forms
> of Indic character might be different from 4-form model.

The init/medi/fina/isol features are used as such for those scripts indeed.
But the OpenType feature tag repository defines init/medi/fina for non-cursive
scripts this way:

'fina':
Function: Replaces glyphs at the ends of words with alternate forms designed
for this use. This is common in Latin connecting scripts, and required in
various non-Latins like Arabic.

'init':
Function: Replaces glyphs at the beginnings of words with alternate forms
designed for this use. This is common in Latin connecting scripts, and
required in various non-Latins like Arabic.

'medi':
Function: Replaces glyphs in the middles of words (i.e. following a beginning
and preceding an end) with alternate forms designed for this use. Note: This
is different from the default form, which is designed for stand-alone use.
This is common in Latin connecting scripts, and required in various non-Latins
like Arabic.

Merging the cursive and non-cursive uses into the same feature is very broken
IMO, but that's life / OpenType.

behdad


https://www.microsoft.com/typography/otspec/features_fj.htm#fini
https://www.microsoft.com/typography/otspec/features_fj.htm#init
https://www.microsoft.com/typography/otspec/features_ko.htm#medi