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RE: textDecoration question

From: Michael Dolan <mdolan@newtbt.com>
Date: Mon, 13 May 2013 20:23:08 -0700
To: "'public-tt'" <public-tt@w3.org>
Message-ID: <009f01ce5052$6653a060$32fae120$@newtbt.com>
Indeed, this is explicit.


So, do a bit of copy/paste with the regex and we’re there….


From: Glenn Adams [mailto:glenn@skynav.com] 
Sent: Monday, May 13, 2013 8:17 PM
To: Michael Dolan
Cc: public-tt
Subject: Re: textDecoration question


CSS 2.1 Section


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


On Mon, May 13, 2013 at 8:02 PM, Michael Dolan <mdolan@newtbt.com> wrote:

Although I agree the order it not relevant, how does one infer that from the defined syntax which is clearly ordered?


From: Glenn Adams [mailto:glenn@skynav.com] 
Sent: Monday, May 13, 2013 4:26 PM

To: Michael Dolan
Cc: public-tt
Subject: Re: textDecoration question


I don't think that's correct, since it doesn't account for the fact that the appearance of the 1, 2, or 3 tokens (when the value isn't none) is in an arbitrary order.


That is, the legal values are:









noUnderline noLineThrough

noLineThrough noUnderline

noUnderline lineThrough

lineThrough noUnderline

underline noLineThrough

noLineThrough underline

underline lineThrough

lineThrough underline

noUnderline noOverline

noOverline noUnderline

noUnderline overline

overline noUnderline

underline noOverline

noOverline underline

underline overline

overline underline

noUnderline noLineThrough noOverline

noUnderline noOverline noLineThrough

noLineThrough noUnderline noOverline

noLineThrough noOverline noUnderline

noOverline noUnderline noLineThrough

noOverline noLineThrough noUnderline

noUnderline noLineThrough overline

noUnderline overline noLineThrough

noLineThrough noUnderline overline

noLineThrough overline noUnderline

overline noUnderline noLineThrough

overline noLineThrough noUnderline

noUnderline lineThrough noOverline

noUnderline noOverline lineThrough

lineThrough noUnderline noOverline

lineThrough noOverline noUnderline

noOverline noUnderline lineThrough

noOverline lineThrough noUnderline

noUnderline lineThrough overline

noUnderline overline lineThrough

lineThrough noUnderline overline

lineThrough overline noUnderline

overline noUnderline lineThrough

overline lineThrough noUnderline

underline noLineThrough noOverline

underline noOverline noLineThrough

noLineThrough underline noOverline

noLineThrough noOverline underline

noOverline underline noLineThrough

noOverline noLineThrough underline

underline noLineThrough overline

underline overline noLineThrough

noLineThrough underline overline

noLineThrough overline underline

overline underline noLineThrough

overline noLineThrough underline

underline lineThrough noOverline

underline noOverline lineThrough

lineThrough underline noOverline

lineThrough noOverline underline

noOverline underline lineThrough

noOverline lineThrough underline

underline lineThrough overline

underline overline lineThrough

lineThrough underline overline

lineThrough overline underline

overline underline lineThrough

overline lineThrough underline





On Mon, May 13, 2013 at 12:37 PM, Michael Dolan <mdolan@newtbt.com> wrote:

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 Tuesday, 14 May 2013 03:24:24 UTC

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