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Re: Don's question

From: Lofton Henderson <lofton@rockynet.com>
Date: Sun, 25 Jan 2009 17:24:36 -0700
Message-Id: <5.1.0.14.2.20090125172027.03c0e7d0@localhost>
To: David Cruikshank <dvdcruikshank@gmail.com> (by way of Lofton Henderson <lofton@rockynet.com>), WebCGM WG <public-webcgm-wg@w3.org>
Dave,

I think you missed Forrest's later message about this:
http://lists.oasis-open.org/archives/cgmo-webcgm/200901/msg00057.html

He pointed this out:  dashLength is a sub-element of 
lineEdgeTypeDef.  I.e., it is an element in the content model of 
lineEdgeTypeDef.  Forrest is correct, according to the DTDs.  Therefore, 
dashLength should precede the close tag of lineEdgeTypeDef.

That aside, I agree that it is a matter of taste whether to make things 
attributes or elements.  I'm not one (XML expert), but I understand that 
XML experts fight religious wars about element-or-attribute.  Myself, I'm 
content to live with your choice (or any other).

However, there is another issue to clarify

It [2] says: "The dashLength element is a string, in the encoding of the 
ACI file, that contains a list of non-negative integers in the format of 
the WebCGMString List-of-number subtype. The integers specify the lengths 
of each dash and gap in the defined line pattern in abstract units, that 
are then normalized as a whole pattern to the repeatLength attribute of 
lineEdgeTypeDef. The first integer corresponds to solid, the second to gap, 
the third to solid, etc."

That seems to clearly say that you can put the whole sequence into the 
CDATA content of one dashLength element.

So this raises a new issue for clarification:  since the content model says 
dashLength+, then what happens with 2 (or 3, or more) occurrences of 
dashLength?

1.) last one wins;
2.) or, the integer list accumulates.

Your example (below) would suggest #2.

Thoughts?

(I'll redirect your answer if you like.)

-Lofton.

[1] http://lists.oasis-open.org/archives/cgmo-webcgm/
[2] 
http://www.w3.org/Graphics/WebCGM/drafts/current-editor-21/WebCGM21-Config.html#ACI-ledtdef



At 05:12 PM 1/25/2009 -0700, David Cruikshank wrote:
>[...redirected to TC list by Lofton...]
>
>I can't respond to the TC email list, so I'm sending my response this way.
>
>Don asked about the content model for the aci:
>
>
>
>
>I'm directing this question to you since you created the ACI DTD
>and perhaps could shed some light on this and at the same time
>
>confirm my XML coding.
>
>dashLength is defined as an Element rather than as an Attribute of
>lineEdgeTypeDef, thus an example the the XML encoding I believe
>would be-
>
><webcgmConfig
>     <lineEdgeTypeDef lineIndex="1"
>repeatLength="100"
>
>     </lineEdgeTypeDef>
>     <dashLength>"10 2 5
>2"</dashLength>
></webcgmConfig>
>
>
>However it seems more natural for dashLength to be an Attribute and
>coded like this:
>
>
><webcgmConfig
>     <lineEdgeTypeDef lineIndex="1"
>repeatLength="100"
>      dashLength="10 2 5 2"
>     </lineEdgeTypeDef>
></webcgmConfig>
>
>This also applies to the directionVectors and gapWidth Elements
>
>assocaited with the hatchStyleDef.
>
>
>
>My response:
>
>When things are repeatable, I've tended to make them repeating elements as 
>opposed to attributes.  I think the correct encoding for your example is:
>
>
><webcgmConfig
>   <lineEdgeTypeDef lineIndex="1" repeatLength="100"
>   </lineEdgeTypeDef>
>   <dashLength>10</dashLength>
>    <dashLength>2</dashLength>
>    <dashLength>5</dashLength>
>    <dashLength>2</dashLength>
></webcgmConfig>
>
>Remember dashLength is specified as "dashLength+".  That way no parsing is 
>required to figure out the values.
>
>If people want parse, it's ok but this was an attempt to simplify the work.
>
>
>Dave
Received on Monday, 26 January 2009 00:25:44 GMT

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