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Re: More on getObjectExtent()

From: Lofton Henderson <lofton@rockynet.com>
Date: Wed, 19 Nov 2008 09:45:29 -0700
Message-Id: <>
To: "David Cruikshank" <dvdcruikshank@gmail.com>
Cc: "WebCGM WG" <public-webcgm-wg@w3.org>

At 08:32 AM 11/19/2008 -0800, David Cruikshank wrote:
>I would agree with dropping "abstract".  Locus is a perfectly valid term 
>to define the path of the primitive.
>Probably ought to capture it somewhere to document the decision.

Just to clarify that last sentence -- you mean that you support the issue 
processing proposal to roll it into Issue3 in the DoC (see URI below)?


>On Wed, Nov 19, 2008 at 8:04 AM, Lofton Henderson 
><<mailto:lofton@rockynet.com>lofton@rockynet.com> wrote:
>>At 09:26 AM 11/19/2008 -0500, Bezaire, Benoit wrote:
>>>I think the wording should be revised.
>>Fair enough.
>>>Even Google doesn't come up with anything meaning full for "Abstract locus".
>>However, it does give lots of hits for a search like "definition of 
>>mathematical locus".  And we use "locus" repeatedly, in the proper sense, 
>>in the profile (Ch.6) -- i.e., "locus" is a pretty common term in  and 
>>has been used in WebCGM, for example, since 1999.  So it is my 
>>hastily-invented modifier "abstract" that is problematic.
>>Actually, I think a good solution would be to drop the word 
>>"abstract".  The next sentence after its occurrence fully explains what 
>>"abstract" was meant to convey.  (And we have agreed to clarify that sentence.)
>>(See the getObjectExtent definition in 5.7.6:
>>(Shall I just add this to fix to the clarification in DoC #3:
>>>From: Lofton Henderson 
>>>Sent: Tuesday, November 18, 2008 6:52 PM
>>>To: Bezaire, Benoit; WebCGM WG
>>>Subject: Re: More on getObjectExtent()
>>>At 01:52 PM 11/18/2008 -0500, Bezaire, Benoit wrote:
>>>>The wording says "[...] The bounding box calculation is based on the 
>>>>abstract locus of the primitives within the APS."
>>>>What does 'abstract locus' mean?
>>>The locus is the set of points comprising the drawn primitive (it's a 
>>>term I dredged up from my memory of some old math courses -- I hope I 
>>>got it right).  "Abstract locus" means that things like line width are 
>>>not included, but rather only the point positions as if the item were 
>>>drawn with an abstract, infinitely fine pen.
>>>>I'd like to know if getObjectExtent() returns a tight bounding box on a 
>>>>given APS. i.e., given a polybezier, are control points part of the 
>>>>bounding box calculations or not?
>>>No.  The control points are part of the defining data, but not part of 
>>>the drawn primitive.
Received on Wednesday, 19 November 2008 16:46:46 UTC

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