ISSUE-214 (negative padding): Negative padding lengths should be prohibited. [TTML 1.0]

ISSUE-214 (negative padding): Negative padding lengths should be prohibited. [TTML 1.0]

http://www.w3.org/AudioVideo/TT/tracker/issues/214

Raised by: Glenn Adams
On product: TTML 1.0

I just noticed that, unlike fontSize and lineHeight, we don't specify that padding lengths must be non-negaive. Rather we have the following language:

"If a specified value of this attribute is not supported, then a presentation processor must interpret the attribute as if the value 0px were specified."

I believe this was an oversight, since CSS 2 [1] states

"Unlike margin properties, values for padding values cannot be negative."

[1] http://www.w3.org/TR/2008/REC-CSS2-20080411/box.html#padding-properties

To resolve, I will add language proscribing negative lengths to section 8.2.1.6 [2].

[2] https://dvcs.w3.org/hg/ttml/raw-file/default/ttml10/spec/ttaf1-dfxp.html#style-attribute-padding

Received on Sunday, 26 May 2013 02:25:59 UTC