[HarfBuzz] Rendering Thai

[Theppitak Karoonboonyanan]

Hi,

Thank you for putting Thai support issue on the table.

Waree contains GSUB rules for proper substitutions, while Tahoma does not.
Legacy fonts like Tahoma rely on composition-by-substitution, and requires the
rendering engine to properly pick up IPA glyphs with vendor-specific
code points.

LibThai has such routine for both Windows and Mac. That's why the Qt patch
helps.

But I think harfbuzz default behavior should at least normalize the combining
characters properly without the patch.

Regards,
-- 
Theppitak Karoonboonyanan
http://linux.thai.net/~thep/


On Thu, Nov 10, 2011 at 9:54 PM, John Tapsell <johnflux at gmail.com> wrote:
> The harfbuzz-thai patch at:
>
> http://linux.thai.net/websvn/wsvn/software.qt/trunk/qt-everywhere-opensource-4.7.0/?#ad73b806583aa98bb601f6b456fa92491
>
> Along with installing libthai solves the rendering problem.
>
> Could someone have a look and tell me what they think please?
>
> John
>
>
> On 10 November 2011 14:24, John Tapsell <johnflux at gmail.com> wrote:
>> Hi,
>>
>>  With harfbuzz.old (Qt's version), when I render the string: "«éÓ" I
>> get the output:
>>
>> http://imageupload.org/download.php?id=132574&type=2
>>
>> W = Waree font
>> T = Tahoma font
>> N = Nokia Pure Text AS font
>>
>> The first one is rendered correctly.  The "o" thingy is rendered in
>> the right place.  The second and third ones are incorrectly rendered.
>>
>> I get the same, incorrect, result with harfbuzz-ng, using the command:
>>
>> ./hb-view --annotate tahoma.ttf "«éÓ" > thai.png
>>
>> It renders incorrectly in openoffice and correctly in gedit, using
>> Tahoma for both.
>>
>> John
>>
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