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RE: textDecoration question

From: Michael Dolan <mdolan@newtbt.com>
Date: Mon, 13 May 2013 11:37:26 -0700
To: "'public-tt'" <public-tt@w3.org>
Message-ID: <00ef01ce5008$ec3faec0$c4bf0c40$@newtbt.com>
Feel free to use this:


            <xs:simpleType name="textDecoration">

                        <xs:restriction base="xs:string">

                                    <xs:pattern value="none|((underline|noUnderline)|(lineThrough|noLineThrough)|(overline|noOverline))|((underline|noUnderline) (lineThrough|noLineThrough))|((lineThrough|noLineThrough) (overline|noOverline))|((lineThrough|noLineThrough) (overline|noOverline))|((underline|noUnderline) (lineThrough|noLineThrough) (overline|noOverline))"/>




From: Glenn Adams [mailto:glenn@skynav.com] 
Sent: Monday, May 13, 2013 10:33 AM
To: Michael Dolan
Cc: public-tt
Subject: Re: textDecoration question


Just added a note (in 8.2.19) and changed schema data type to xs:string.


On Mon, May 13, 2013 at 8:45 AM, Michael Dolan <mdolan@newtbt.com> wrote:

I’d suggest adding text clarifying this and of course, the schema should be fixed.


From: Glenn Adams [mailto:glenn@skynav.com] 
Sent: Sunday, May 12, 2013 5:50 PM
To: Michael A Dolan
Cc: public-tt
Subject: Re: textDecoration question



On Fri, Jun 22, 2012 at 6:00 PM, Michael A Dolan <mdolan@newtbt.com> wrote:

The prose for this attribute is not clear whether combinations of the pairs of attributes can be used.  The examples show only a single value at a time – e.g. either underline or lineThrough.


The syntax is constructed in an unusual manner if the intent was to only permit a single value.  The schema is currently an enumeration, forcing only a single value.


To understand the notation, you have to trace back to XSL-FO and thence to CSS 2. See [1].


[1] http://www.w3.org/TR/CSS2/about.html#value-defs




A double bar (||) separates two or more options: one or more of them must occur, in any order.


This would probably be more clear if someone hadn't removed the references to the XSL-FO definitions upon which the properties were based, though you can still trace it via Appendix J.2 Attribute Derivation [2].


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


In any case, the intent is not to permit a single value, e.g., "underline overline noLineThrough" is a valid value.



If the schema is correct, then one can never apply both underline and lineThrough concurrently – e.g. textDecoration=”underline lineThrough”.


Does the schema reflect the intent?  If so, then why the odd construction of the syntax in the prose?






Michael A DOLAN

Television Broadcast Technology, Inc

PO Box 190, Del Mar, CA 92014 USA

+1-858-882-7497 <tel:%2B1-858-882-7497>  (m)



Received on Monday, 13 May 2013 18:38:08 UTC

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