Re: Comment added to inline box issue

> Of course, once we define our keyword, we can officially ask the CSS WG to define an equivalent on height in a future document that would apply to non-replaced inline boxes.

Since we seem to know the semantic we need, it would be helpful to add a comment to the CSS issue to describe that semantic or to confirm that it is indeed the same as what it being proposed for "height: stretch". I suggest we discuss this on the call later and assign this action to someone here.

Nigel


From: Glenn Adams <glenn@skynav.com<mailto:glenn@skynav.com>>
Date: Thursday, 20 April 2017 at 09:11
To: Dae Kim <dakim@netflix.com<mailto:dakim@netflix.com>>
Cc: Nigel Megitt <nigel.megitt@bbc.co.uk<mailto:nigel.megitt@bbc.co.uk>>, Timed Text Working Group <public-tt@w3.org<mailto:public-tt@w3.org>>
Subject: Re: Comment added to inline box issue



On Wed, Apr 19, 2017 at 3:07 PM, Dae Kim <dakim@netflix.com<mailto:dakim@netflix.com>> wrote:
David and Eleka both feel any solution for this should end up in CSS Inline Level 3<https://drafts.csswg.org/css-inline/>. Based on our own TTML2/IMSC2 timelines, the best we can realistically hope for in terms of a CSS solution is a WD or ED while we're preparing for TTML2 Rec.

Given how new this stretch concept is (and assuming other members of CSS are on board), do we feel comfortable baking TTML2/IMSC2 with a CSS draft concept?

The suggested approach, of adding a keyword to the height property, is effectively the same as we have proposed [1], which is to add keywords to a new style property tts:bpdContent or an existing style property tts:bpd.

In that proposal, we had suggested a new property tts:bpdContent since tts:bpd was used to trigger inline-block semantics. However, when we reviewed this in London, we decided to drop this special trigger semantic (and instead use explicit semantics via a new "inlineBlock" value on tts:display). This will allow us to use tts:bpd to solve this problem (about the 'height' of inline non-replaced elements) instead of introducing a new property tts:bpdContent.

So, in the end, we have tts:bpd="bpdLine" or tts:bpd="bpdLineLeaded" as the way to designate that the content height of the inlines should stretch or fill the line area height up to and either excluding or including leading.

In other words, where a future CSS Inline Level 3 might have "height: stretch" we would have "tts:bpd='bpdLineLeaded'", i.e., the height of the line area's content area plus the height of leading. Of course, this would depend on the CSS WG defining "stretch" or some other keyword with equivalent semantics.

[1] https://github.com/w3c/ttml2/issues/150#issuecomment-192490492

I suggest we go ahead with defining whichever keywords we want to use with tts:bpd, and not create a highly risky dependency on a future CSS Inline Level 3 document an equivalent keyword. Of course, once we define our keyword, we can officially ask the CSS WG to define an equivalent on height in a future document that would apply to non-replaced inline boxes.



-Dae

Dae Kim | Senior Video Engineer | Encoding Technology
9420 94f4 a834 b038 2920 34b3 38ad b632 3738 942c 942f

On Wed, Apr 19, 2017 at 9:49 AM, Nigel Megitt <nigel.megitt@bbc.co.uk<mailto:nigel.megitt@bbc.co.uk>> wrote:

For those not following the issue on github there has been a response about the request to be able to set the background height of inline areas – see https://github.com/w3c/csswg-drafts/issues/814#issuecomment-295122693

Nigel




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