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Re: [css-text] i18n-ISSUE-354: Questions about letter-spacing for Arabic script

From: fantasai <fantasai.lists@inkedblade.net>
Date: Tue, 16 Aug 2016 14:47:28 -0700
To: www-style@w3.org, 'WWW International' <www-international@w3.org>
Message-ID: <d1bd3e23-e3ce-fdf7-77d0-5e9bf19a7513@inkedblade.net>
On 10/23/2014 03:08 AM, Richard Ishida wrote:
> On 01/08/2014 15:02, fantasai wrote:
>> On 07/25/2014 07:57 PM, Richard Ishida wrote:
>>> 8.2 Tracking: the letter-spacing property
>>> http://dev.w3.org/csswg/css-text/#letter-spacing-property
>>> Editor’s Draft, 20 March 2014
>>>
>>> The length value has the description:
>>>
>>> "Specifies additional spacing between visually-perceived characters.
>>> Values may be negative, but there may be implementation-dependent
>>> limits."
>>>
>>> For cursive text the spec says:
>>>
>>> "If it is able, the UA may apply letter-spacing to cursive scripts by
>>> translating the total spacing distributed to a run of such letters
>>> into some form of cursive elongation for that run."
>>>
>>> Does this mean that if tracking length is set to 1em for a word that
>>> is 6 letters long, that the total length of the resulting text will
>>> be 6em plus the letter widths, and that therefore if there are some
>>> letters that are not allowed to elongate the others will elongate
>>> wider than 1em? Or does it mean that those letters that can stretch
>>> will each stretch by 1em (possibly resulting in less than 6em overall
>>> width)?
>>
>> The former.
>>
>>> If values are negative, does this have any meaning for cursive scripts,
>>> or is it a hint to use ligatures if any are available
>>> (which will result in different effects per font)?
>>
>> This would allow the use of shortening ligatures or contextual forms,
>> yes.
>>
>>> And then there are Arabic font styles that don't elongate, such as
>>> ruq'a. Does the application have to disable letter-spacing  if the
>>> user or the device chooses a ruq'a-style font, or is that the
>>> responsibility of the author? It seems that it might be
>>> hard for authors to signal what to do in the case of fallback fonts.
>>
>> The application should disable any elongation, yes. It seems unlikely
>> for a ruqu'a-style font to be a fallback font, however: system fonts
>> are much more likely to be the newspaper style of writing.
>
>
> The i18n WG is hoping that you can add some of the above clarifications
> to the spec, so that we can close this issue.

We've made some clarifications. Please take a look at the section and let
me know if this issue is resolved.

Thanks~
~fantasai
Received on Tuesday, 16 August 2016 21:48:04 UTC

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