[HarfBuzz] Fwd: Where to report a bug with Tamil text rendering in LibreOffice?

Behdad Esfahbod behdad at behdad.org
Thu Aug 25 14:32:38 PDT 2011


On 08/24/11 19:07, Shriramana Sharma wrote:
> On Wed, Aug 24, 2011 at 4:40 PM, Behdad Esfahbod <behdad at behdad.org> wrote:
>> Note that these clusters are not used, or should not be used, for cursor
>> movement.  '
> 
> Then what are they used for?

They are used to map glyphs to characters, such that when the toolkit decided
where in the character stream it wants to put the cursor, it can map it to the
(x,y) position on the screen.


>> Cursor movement should work according to the UAX#29.
> 
> OK fine, but still the Tamil issue applies, as the above standard reads:

That's not HarfBuzz's job, but HarfBuzz does happen to get this right.

behdad

> """Indic scripts vary considerably in how they handle the rendering of
> such aksaras—in some cases stacking them up into combined forms known
> as consonant conjuncts, and in other cases stringing them out
> horizontally, with visible renditions of the halant on each consonant
> in the sequence. There is even greater variability in how the typical
> liquid consonants (or "medials"), ya, ra, la, and wa, are handled for
> display in combinations in aksaras. So tailorings for aksaras may need
> to be script-, language-, font-, or context-specific to be useful."""
> 
> "stringing out horizontally with visible renditions of the halant on
> each consonant in the sequence" applies to Tamil. Hence tailoring is
> necessary.
> 



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