Re: Caret

From: Philippe Verdy <verdy_p_at_wanadoo.fr>
Date: Sun, 25 Nov 2012 02:51:52 +0100

Will it be also cool if the caret decomposes a single precomposed Hangul
cluster, to allow editing only the leading or middle jamo, and recomposing
the Hangul cluster ?

Same thing in automated search-replace operations (I think it is another
problem than just the caret, it is related to collation algorithms and
preserving the normalization form, but it is complexified a lot in regular
expressions, just like with other precomposed character containing
combining diacritics) ?

And what about applying separate styles on components of a cluster (e.g.
different color to an acute accent) : the difficulty is even worse due to
selection of fonts and the way text renderers are selecting glyphs in fonts
and positioning/substituting them (it does not work if glyphs are in
distinct fonts or if sequences are only rendered correctly by fonts
performing substitutions).

It is also very complex for fonts that are describing complex substitutions
(notably in cursive scripts, like Arabic in the Eastern styles as used in
Farsi and Urdu) : here also renderers won't know what to do unless fonts
contain much more instructions for indicating the position of a caret in a
joining form or in a ligatured form (generally renderers can still infer an
approximate linear computation, but for Arabic whose letters have extremely
variable widths, linear computation of an approximative position does not
work at all).

2012/11/25 Doug Ewell <doug_at_ewellic.org>

> Philippe Verdy wrote:
>
> Having the possibility to position a caret in the middle of an Hangul
>> cluster, between two conjoined jamos, is a challenge as it is clear
>> that it will be difficult to determine the position, size and glyph to
>> use for a caret positioned in the composed cluster.
>>
>
> Yes, but you have to admit it would be really cool.
>
> --
> Doug Ewell | Thornton, Colorado, USA
> http://www.ewellic.org | @DougEwell
>
Received on Sat Nov 24 2012 - 19:55:30 CST

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