[HarfBuzz] How to use 'locl' feature of Noto Sans CJK with Harfbuzz?

[Behdad Esfahbod]

On 15-05-06 02:30 PM, Adam Twardoch (List) wrote:
> Behdad, 
> 
> Can you confirm my understanding is that in HB:
> 
> 1. For the script tags, one must use the ISO-style ("high level") script tags to get script-specific shaping. You once told me the trick that using OT-style ("low-level") script tags would disable the script-specific shaper but still execute the OT features blindly. 
> 
> 2. For the language tags, one should use high-level ISO-style language tags, while the low-level OT languagesystem tags "might" work, but it's not recommended to use them. 
> 
> So overall, one should use the ISO-style codes. 

Correct.  The HarfBuzz API is OpenType-agnostic.  When we need to map
script/language tags from the API to OpenType, we try mapping known entries
and if that fails, we use the tag as is (after fixing upper/lower case).

Language tags are actually BCP 47.

Also, if one wants to override OpenType language system directly, they can use
a BCP 47 extension tag like "x-hbotZHT" for example.
Or, eg, "zh-x-hbotZHT".

b

> A.
> 
> Sent from my mobile phone.
> 
>> On 06.05.2015, at 22:40, Behdad Esfahbod <behdad.esfahbod at gmail.com> wrote:
>>
>>> On 15-05-06 08:08 AM, Richard Wordingham wrote:
>>> It should just be hb_buffer_set_language(buffer,
>>>                                         hb_tag_from_string(LANG));
>>>
>>> where lang is one of the following four-character strings:
>>>
>>> "JAN " for Japanese
>>> "KOR " for Korean
>>> "ZHH " for Hong Kong
>>> "ZHS " for Simplified Chinese
>>> "ZHT " for Traditional Chinese
>>
>> This might work, but preferred way is:
>>
>> "ja" for Japanese
>> "ko" for Korean
>> "zh-hk" for Hong Kong
>> "zh-hans" or "zh-cn" for Simplified Chinese
>> "zh-hant" or "zh-tw" for Traditional Chinese
>>
>> b
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>