[HarfBuzz] A problem in thai shaper

Behdad Esfahbod behdad at behdad.org
Tue Apr 17 18:22:21 PDT 2012

On 04/17/2012 06:47 PM, Khaled Hosny wrote:
> On Tue, Apr 17, 2012 at 05:10:37AM +0200, Khaled Hosny wrote:
>> On Mon, Apr 16, 2012 at 09:08:49PM -0400, Behdad Esfahbod wrote:
>>>> Problem 2:
>>>> When there is no consonant exist, the dotted circle should be inserted as base
>>>> character.  The logic should be the first step for the shaping engine to find
>>>> the invalid combing marks. Refer to
>>>> http://www.microsoft.com/typography/otfntdev/thaiot/shaping.aspx#comb
>>> Right.  We do not handle invalid combining marks yet.  That's something I want
>>> to do at some point but it's not high priority.
>> I don't know about Thai, but the handling of "invalid" Arabic combining
>> marks in Uniscribe is completely brain dead and a real PITA and I'd
>> really like not to see HarfBuzz going there, a shaping engine is not a
>> spell checker and should not enforce any input pattern.
>> http://www.microsoft.com/typography/OpenType%20Dev/arabic/shaping.mspx#invalid
> Incidentally, I came across this Typophile post, which is one example of
> why this "invalid" mark handling is not really a good idea:
> http://typophile.com/node/92130

Interesting.  I'm undecided about this as of now.


> Regards,
>  Khaled

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