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Re: ISSUE-2129 (definition clarifications): Definition section is too long and needs clarifications (bbox, canvas, etc.) [Last Call: SVG 1.2 Tiny ]

From: Cyril Concolato <cyril.concolato@enst.fr>
Date: Tue, 14 Oct 2008 08:05:18 +0200
Message-ID: <48F4369E.2090301@enst.fr>
To: SVG Working Group WG <public-svg-wg@w3.org>

SVG Working Group Issue Tracker a écrit :
> 
> ISSUE-2129 (definition clarifications): Definition section is too long and needs clarifications (bbox, canvas, etc.) [Last Call: SVG 1.2 Tiny ]
> 
> http://www.w3.org/Graphics/SVG/WG/track/issues/2129
> 
> Raised by: Doug Schepers
> On product: Last Call: SVG 1.2 Tiny 
> 
> Cyril Concolato
> <http://lists.w3.org/Archives/Public/www-svg/2008Oct/0110.html>:
> [[
> * Section "1.6 Definition"
> Generally, I think the definition of bounding box is too long to be in the definition sections, it makes the definition section hard to grasp.
For this comment, I propose to move the (unchanged) content of the bounding box definition into a new section called "Bounding Box" before "7.12 Object bounding box units". However, I don't know if adding a new section has impact on the test suite organization for example. If you think this is too much work, then ignore my comment.

> 
> Additionally, the definition of bounding box explicitely excludes some stroke attributes but not others like stroke-dasharray, join, cap. I suggest adding all stroke attributes.
I suggest the following replacement:
"The bounding box must be computed exclusive of any values for the 'fill', 'stroke', 'stroke-width', 'opacity'  or 'visibility'  properties."
With:
"The bounding box must be computed exclusive of any values for the 'fill' property, the opacity-related properties, the stroke-related properties, or the 'visibility' property."

>   
> This definition says:
> "For curved shapes, the bounding box must enclose all portions of the shape along the edge, not just end points, but must not include control points for curves that are not within the shape itself."
> The 'must not' requirement should be changed to a 'should' because depending on the curve and depending on the precision of the implementation (fixed point), it may be impossible to make a bounding box that does not include the control point. 
There was actually a mistake in my comment. The proposed edit is replace:
"For curved shapes, the bounding box must enclose all portions of the shape along the edge, not just end points, but must not include control points for curves that are not within the shape itself."
with
"For curved shapes, the bounding box must enclose all portions of the shape along the edge, not just end points, but should not include control points for curves that are not within the shape itself."

> Could you clarify the meaning of the following sentence especially for the defs element?
> "Elements which do not partake in the rendering tree (e.g. elements in a 'defs'  element, elements whose 'display'  is none, etc.), and which have no child elements that partake in the rendering tree (e.g. 'g'  elements with no children), shall not contribute to the bounding box of the parent element, but must return a bounding box for the sake of calculating their own geometry."
> What does the bounding box of a defs element 'must return (...) for the sake of calculating [its] own geometry.'?
For this comment, I don't know what edit to propose.

> 
> There are two related definitions: canvas and SVG canvas. Do you really need 2 different definitions? Where in the spec do you use canvas with a different meaning than SVG canvas ? It is not clear how these terms are used in the spec. For example, we find: target canvas, current canvas, intermediate canvas, resulting canvas, background canvas, and temporary video canvas.
For this one, I think we could use only one word: canvas, using the definition of SVG canvas. I'm not sure though.

> The definition of "graphics referencing element" misses the foreignObject element, no?
This one is simple, replace:
"The following elements are graphics referencing elements: 'animation', 'image', 'use' and 'video'."
with
"The following elements are graphics referencing elements: 'animation', 'foreignObject', 'image', 'use' and 'video'."

Cyril

-- 
Cyril Concolato
Maître de Conférences/Associate Professor
Groupe Mutimedia/Multimedia Group
Département Traitement du Signal et Images
/Dept. Signal and Image Processing
Ecole Nationale Supérieure des Télécommunications
46 rue Barrault
75 013 Paris, France
http://tsi.enst.fr/~concolat 
Received on Tuesday, 14 October 2008 06:06:07 GMT

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