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RE: [SVGMobile12] Stroke processing model missing

From: Scott Hayman <shayman@rim.com>
Date: Thu, 28 Jul 2005 14:04:08 -0400
Message-ID: <F88DB8752C2F644E91BE66DC3ACFF48008BDF544@XCL01YYZ.rim.net>
To: "Ian Hickson" <ian@hixie.ch>, <www-svg@w3.org>

Hi Ian, 

Thank you very much for the feedback.

> From: Ian Hickson

> There does not appear to be a definition anywhere in the SVG 
> 1.2 Tiny spec of how stroking is actually supposed to be rendered.

It is defined, albeit quite loosely, in Section 11.4 [1].  Based upon
this last call comment and others you've made [2], this section of the
spec has been reviewed and updated in order to ensure that conformance
criteria is correctly specified.

> In 
> fact, I could only find three conformance criteria in the 
> entire section on stroke properties (section 11.4), namely:
> 
>   "In all cases, all stroking properties which are affected by
>   directionality [...] must be rendered such that the stroke operation
>   starts at the same point at which the graphics element starts."

This has be rewritten as follows:

In all cases, strokes which are affected by directionality, such as
those having dash patterns, must be rendered such that the stroke
operation starts at the same point at which the graphics element starts.

>   "For stroking properties such as dash patterns whose 
> computations are
>   dependent on progress along the outline of the graphics element,
>   distance calculations are required to utilize the SVG user agent's
>   standard Distance along a path algorithms."

This paragraph has been rewritten as follows:

For strokes, such as dash patterns whose computations are dependent on
progress along the outline of the graphics element, distance
calculations must use the SVG user agent's standard Distance along a
path algorithms.

> The first of these seems meaningless -- I don't understand 
> what it means to "render" a "stroking property".

I agree.  Please see above for an updated version of the text.

> The second 
> is an empty statement since the spec does not define any 
> stroking property computations as far as I can tell. 

I agree.  Please see above for an updated version of the text.

> The 
> third could be a definition of how stroking should work, I 
> guess, except that it limits itself to "complex paint 
> servers", which leaves the question of how to render solid 
> strokes unanswered, and it relies on a geometry of the 
> stroking properties, which is not defined.

The rendering of solid strokes should now be much clearer with the spec
updates that have been done to clearly identify the conformance
criteria.

Regards,
Scott

[1] http://www.w3.org/TR/SVGMobile12/painting.html#StrokeProperties
[2] http://lists.w3.org/Archives/Public/www-svg/2005May/0141.html



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Received on Thursday, 28 July 2005 18:04:16 GMT

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