Re: [css-writing-modes] computed value for text-orientation: sideways or sideways-right

On 09/17/2015 05:42 PM, Gérard Talbot wrote:
> Le 2015-09-17 06:51, Jonathan Kew a écrit :
>> The recently-updated draft[1] says:
>>
>> # Name:           text-orientation
>> # Value:          mixed | upright | sideways-right | sideways
>> # ...
>> # Computed value: specified value
>>
>> Given that 'sideways' and 'sideways-right' are defined to be
>> equivalent, could/should we change this such that 'sideways-right'
>> computes to 'sideways' (or possibly vice versa)? Then the UA can treat
>> this as a simple alias during parsing, and avoid the need to keep
>> track of the specified value just so that getComputedStyle() can
>> return it correctly.
>>
>> Which of 'sideways' or 'sideways-right' do we want to promote as the
>> "canonical" computed value, and which should be an alias? (My vote
>> goes to the simpler 'sideways', fwiw.)
>>
>> JK
>>
>> [1] https://drafts.csswg.org/css-writing-modes-3/#propdef-text-orientation
>
> I believe that 'sideways' should just be removed. Just my opinion.
>
> If, one day, 'sideways-left' is reintroduced, then we should also
> reintroduce 'sideways' like in the original intent of the spec,
> meaning :
>
> "'sideways' value is equivalent to sideways-right in vertical-rl
> writing mode and equivalent to sideways-left in vertical-lr
> writing mode."

Since the use cases for the automatic rotation are mainly for
horizontal scripts, and these will be using the new 'sideways-lr'
and 'sideways-rl' values of 'writing-mode', there might not be
much need for such a value in the future. It seems to me it would
be better to optimize for the CJK users who will need to use the
'text-orientation' property with much more frequency, and so it
makes sense to use a shorter name.

The alternative, which may still be possible depending on the
status of implementations and Web content, would be to drop
both values and use 'sideways-rl' as a keyword:

   text-orientation: upright | mixed | sideways-rl

(EPUB content should be using -epub- prefixed syntax, so would
not be affected.)

> By the way, Example 8 in
> https://drafts.csswg.org/css-writing-modes-3/#text-orientation
> no longer makes perfect sense now that sideways-left has been removed.

Removed. Thanks~
~fantasai

Received on Friday, 18 September 2015 00:30:13 UTC