Re: ISSUE-257: Interpretation of percentage tts:fontSize on root (tt) element

On Tue, Jul 16, 2013 at 6:42 PM, Michael Dolan <mdolan@newtbt.com> wrote:

> Agreed.  The new XML schema currently permits style attributes, and should
> be corrected.
>

This is a side effect of having added ##other to core attributes in
resolving ISSUE-150 [1][2].

[1] http://www.w3.org/AudioVideo/TT/tracker/issues/150
[2]
http://dev.w3.org/cvsweb/2008/tt/spec/xsd/Attic/ttaf1-dfxp-core-attribs.xsd.diff?r1=1.3;r2=1.4;hideattic=0;f=h

I'm not sure it is possible to say ##other minus {ttm,ttp,tts} namespaces,
or at least I haven't tried doing this with XSD.

> ****
>
> ** **
>
> Unrelated, but also about the schema, I thought we had found the
> authoritative xml.xsd on ww3.org a while back and we were going to defer
> to that and not include our own copy?
>
There is a problem with the xml.xsd you refer to [3]: namely, it types
xml:lang as xs:language, but xs:language [4] doesn't admit the empty
string, which is a legal value according to XML 1.0 [5].

[3] http://www.w3.org/2001/03/xml.xsd
[4] http://www.w3.org/TR/xmlschema-2/#language
[5] http://www.w3.org/TR/REC-xml/#sec-lang-tag

> ****
>
> ** **
>
>                 Mike****
>
> ** **
>
> *From:* Glenn Adams [mailto:glenn@skynav.com]
> *Sent:* Tuesday, July 16, 2013 4:49 PM
> *To:* public-tt
> *Subject:* Re: ISSUE-257: Interpretation of percentage tts:fontSize on
> root (tt) element****
>
> ** **
>
> I was reviewing the recently closed ISSUE-257 today, and after further
> consideration, have determined it was incorrect, and needed to be reverted
> which I have done in [1].****
>
> ** **
>
> The basic problem with the previous resolution is that TT Style Attributes
> are not defined for use on the *tt* element (with the exception of the
> special case of tts:extent). Furthermore, the outermost Content element [2]
> used during content style inheritance is the *body* element.****
>
> ** **
>
> Ultimately, there is no element on which tts:fontSize can be specified
> that doesn't have a parent element. In the case of *body*, if no
> tts:fontSize is specified, then region style inheritance comes into effect.
> So that leaves us with a tts:fontSize potentially specified on *region* as
> the outermost inheritable font size. Accordingly, if the region's font size
> is specified in percentage, then we do need to resolve it against something
> other than its parent, since no ancestor of region participates in style
> inheritance.****
>
> ** **
>
> I will now re-implement a fix for this issue based on the need to resolve
> percentage on region. ****
>
> ** **
>
> [1] https://dvcs.w3.org/hg/ttml/rev/0355e9473d7e****
>
> [2]
> https://dvcs.w3.org/hg/ttml/raw-file/default/ttml10/spec/ttaf1-dfxp.html#element-vocab-type-content
> ****
>