Re: Line Height stacking strategy algorithm - approval needed

>  There's no proposal to backport them to TTML1so far

Thanks for confirming.

-- Pierre

On Mon, Jan 20, 2014 at 12:38 AM, Nigel Megitt <nigel.megitt@bbc.co.uk> wrote:
> Hi Pierre,
>
> The 125% wording we added to TTML1SE is informative only. I don't believe
> that the proposed algorithm is contrary to that wording (and certainly not
> to the intent) though it is more explicit about when the percentage rule
> should apply and removes much of the ambiguity present previously.
>
> That said, these changes are planned for TTML2 only. There's no proposal
> to backport them to TTML1so far, but if you or another member would like
> to make one then that option's available.
>
> Kind regards,
>
> Nigel
>
>
> On 17/01/2014 20:46, "Pierre-Anthony Lemieux" <pal@sandflow.com> wrote:
>
>>Hi Nigel,
>>
>>Is the plan to backport these changes to TTML 1.0?
>>
>>Thanks,
>>
>>-- Pierre
>>
>>On Fri, Jan 17, 2014 at 6:17 AM, Nigel Megitt <nigel.megitt@bbc.co.uk>
>>wrote:
>>> CONTEXT
>>>
>>> As discussed in yesterday's TTWG meeting, as part of the fulfilment of
>>> actions 219 [1] and 221 [2] Glenn has edited the TTML2 editor's draft to
>>> incorporate an algorithm for computing the value of line height, based
>>>on
>>> the code used by Mozilla, blink and webkit. This can additionally be
>>> considered part of the solution to the line height problem which has
>>>also
>>> been raised in issues 275 [3] and 284 [4].
>>>
>>> WHAT HAS CHANGED
>>>
>>> The algorithm can be found at [5] in section 8.2.13 tts:lineHeight.
>>>
>>> I won't attempt to repeat Glenn's explanation of this algorithm, which I
>>> scribed as best I could yesterday, except to note what may appear at
>>>first
>>> to be a substantive change to some, that the "125% of fontSize" rule
>>>does
>>> not always apply, but applies only when the font is not associated with
>>> "font metrics that specify altitude A, descent D, and line gap G".
>>>
>>> FOLLOW-UP
>>>
>>> This algorithm is absent from CSS but, if this group's members are happy
>>> with it, we should communicate it to the CSS WG, to maximise the time
>>>for
>>> them to raise any potential issues, or indeed choose to adopt it into
>>>their
>>> own output documentation, which we could then potentially reference.
>>> Formally they will report any problems anyway at Last Call stage but I'd
>>> rather seek early agreement when possible.
>>>
>>> ACTION REQUIRED NOW
>>>
>>> Please notify the group if there are any queries or objections to this
>>> algorithm as it stands.
>>>
>>> We noted in yesterday's call that it was not possible to verify that IE
>>> adopts the same algorithm, so it would be particularly useful if someone
>>> from Microsoft could confirm that they are happy with it ­ Jerry, this
>>> probably means you!
>>>
>>> Rather than making this an open-ended action I'll close this off and
>>>state
>>> that we have approval if there are no outstanding objections by the end
>>>of
>>> our next call on 30th Jan 2014.
>>>
>>>
>>>
>>> This email satisfies Action-260 [6].
>>>
>>>
>>> References
>>>
>>> [1] Action-219 https://www.w3.org/AudioVideo/TT/tracker/actions/219
>>> [2] Action-221 https://www.w3.org/AudioVideo/TT/tracker/actions/221
>>> [3] Issue-275 https://www.w3.org/AudioVideo/TT/tracker/issues/275
>>> [4] Issue-284 https://www.w3.org/AudioVideo/TT/tracker/issues/284
>>> [5] TTML2 Editor's draft, section on lineHeight
>>>
>>>https://dvcs.w3.org/hg/ttml/raw-file/default/ttml2/spec/ttml2.html#style-
>>>attribute-lineHeight
>>> [6] Action-260 https://www.w3.org/AudioVideo/TT/tracker/actions/260
>>>
>>>
>>>
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Received on Wednesday, 22 January 2014 21:52:47 UTC