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Re: Issue-286: application of padding to p etc

From: John Birch <John.Birch@screensystems.tv>
Date: Thu, 5 Dec 2013 18:45:32 +0000
To: "'nigel.megitt@bbc.co.uk'" <nigel.megitt@bbc.co.uk>, "'glenn@skynav.com'" <glenn@skynav.com>, "'public-tt@w3.org'" <public-tt@w3.org>
Message-ID: <0981DC6F684DE44FBE8E2602C456E8AB014F69DA70@SS-IP-EXMB-01.screensystems.tv>
The only potential use case for padding on span is to create a coloured background for span text that extends halfway across the space characters (I.e. Halfway between words), rather than having the background colour finish at the text boundaries (which is a less desirable visual effect).

Since padding applies to layout, rather than background, this is a bit like using an axe as a hammer... I.e. Can be made to work (as Nigel outlined) but is not a good practise!


From: Nigel Megitt [mailto:nigel.megitt@bbc.co.uk]
Sent: Thursday, December 05, 2013 05:25 PM
To: Glenn Adams <glenn@skynav.com>; 'Timed Text Working Group' <public-tt@w3.org>
Subject: Issue-286: application of padding to p etc

Hi Glenn,

I've had a look at your edit that added padding to content elements and I don't believe that this contradicts the usage defined by EBU-TT-D in Issue-286 as written. However we need to describe exactly what padding means when applied to body, div and span, assuming the EBU proposal for the definition on p carries.

body: Since tts:padding is not inheritable and body can not contain content (i.e. what's in the spec as Inline.class)  I'm not sure how it would ever be applied.

div: Could apply to the set of rendered lines within the div, taken as a single rectangle? This is subtly different from padding on region, which doesn't take into account the width of the rendered lines at all, so I can see it being useful.

p: as per proposal, applies separately to each rendered line within the p.

span: applies to the contained text within the span. Adds to or overrides p-based tts:padding values? Either way this is the most problematic one: the padding creates spacing that is normally created using a spacing text character, which gives the author a no-win problem: either create spans with padding to make spacing correct, and remove space characters from text, or have unwanted extra spacing, dependent on line wrapping. The cost of removing space characters from the text is that meaning is removed – some processors might for example pre-process by removing all formatting (e.g. for indexing), leading to weird compound words where the space has been removed.

Kind regards,




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Received on Thursday, 5 December 2013 18:46:03 UTC

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