Re: Issue-286 padding

On further reflection EBU decided to avoid potential causing confusion by overloading padding on p in the way originally described, and refactored the proposed solution to meet strictly the original requirement:

It is now an attribute called ebutts:linePadding.
It is an inherited property that is applied to rendered lines within block elements.
It has a single value that is applied equally to the start and end edges of each line and not to before and after edges.
The unit permitted is a non-negative number with option decimal fraction followed by "c", i.e it uses the c metric.
Each line area is extended by the distance specified.
The maximum available inline progression distance in which foreground text may be laid out on a single line in a block element is diminished by 2x the linePadding distance.
The background color that applies at each start and end edge is used to extend the background color fill within the extended line area.

The attached diagram replaces the previously circulated diagram and exemplifies most of the above (in this case for left justified lines).

Nigel



On 04/12/2013 16:11, "Nigel Megitt" <nigel.megitt@bbc.co.uk<mailto:nigel.megitt@bbc.co.uk>> wrote:

Specifically on padding, the EBU discussed this requirement further last week and agreed that the requirement that foreground layout must not be affected can be relaxed: even though it's not the ideal solution it does have a safe fallback. This in turn permitted a revised requirement that should be easier to implement in CSS and can be expressed as a definition of tts:padding on <p>, which is currently not defined in TTML. The attached diagram explains the expected behaviour, i.e. that padding is applied to each rendered line and acts very much like a line-based version of region padding.

Note that this solution does not define <span> based padding which wouldn't really work here – the padding would interfere with intended spacing. However EBU does not have a requirement for this.

Nigel

On 13/11/2013 16:07, "Glenn Adams" <glenn@skynav.com<mailto:glenn@skynav.com>> wrote:

The attached shows the difference between putting the background/padding on span versus p. Take your pick.



On Wed, Nov 13, 2013 at 12:15 PM, Nigel Megitt <nigel.megitt@bbc.co.uk<mailto:nigel.megitt@bbc.co.uk>> wrote:

Thanks Glenn,

I'm not sure this meets the described rowPadding requirements - the padding appears to be attached to the <p> not the rendered rows of text, so if an automatic (i.e. not explicit) line break is inserted the padding isn't added to the new rows. Is there a way to extend it to do that as well?

Nigel

________________________________
From: Glenn Adams [glenn@skynav.com<mailto:glenn@skynav.com>]
Sent: 13 November 2013 03:03
To: TTWG
Subject: Re: row align and padding

Here's are two versions that work on Safari. For Safari 6.0.5 or earlier, use the one labeled old syntax. For 6.1 and 7.0, use the other (which uses new syntax). Safari still requires use of the "-webkit-" prefix in both cases.


On Wed, Nov 13, 2013 at 5:09 AM, Glenn Adams <glenn@skynav.com<mailto:glenn@skynav.com>> wrote:
Simplified and clean up example, using single <p> for each caption's text (instead of separate p per line).


On Tue, Nov 12, 2013 at 5:56 PM, Glenn Adams <glenn@skynav.com<mailto:glenn@skynav.com>> wrote:
The attached uses to CSS3 Flexbox and a few other properties to produce the desired effects for the row align and padding examples I've seen. It works on current versions of Chrome, Firefox, and Opera. It doesn't seem to work on Safari 6.0.5. I haven't tested IE, but supposedly IE10 and following supports Flexbox.





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