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Re: ISSUE-2137 (canvas negotiation begin time): Add clarification about begin time for canvas negotiation (ACTION-2320)

From: Doug Schepers <schepers@w3.org>
Date: Fri, 17 Oct 2008 23:35:31 -0400
Message-ID: <48F95983.9010900@w3.org>
To: cyril.concolato@telecom-paristech.fr
CC: SVG Working Group WG <public-svg-wg@w3.org>

Hi, Cyril-

Cyril Concolato wrote (on 10/14/08 2:36 AM):
> 
> SVG Working Group Issue Tracker a écrit :
>>
>> ISSUE-2137 (canvas negotiation begin time): Add clarification about
>> begin time for canvas negotiation [Last Call: SVG 1.2 Tiny ]
>>
>> http://www.w3.org/Graphics/SVG/WG/track/issues/2137
>>
>> 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 7.1. Coordinate Systems, Transformations and Units Introduction
>> Could you add a clarification about when the canvas negotiation
>> happens? I think it happens upon parsing the start tag of the SVG root
>> element but this is not clear. 
>
> More precisely, I suggest adding the following sentence in the
> progressive rendering section (5.9.2) after the sentence:
> "The following rules apply to progressive rendering:"
> "* the negotiation process for the size of the SVG viewport (see
> Establishing the size of the initial viewport) happens when the
> start-tag of the rootmost 'svg' element has been processed."
> 
> This clarification is needed because I think that since script elements
> can have access to the viewport width/height, the negotiation has to
> happen before any script is processed.

Your reasoning and wording are sound, but this is actually
implementation-specific.  It could happen at parse-time, or rendering
time, or any time in between.

It may be even out of the control of the SVG user agent, for example if
the SVG is embedded in an HTML page, the viewport size may not be a
function of the SVG root settings, and may change as a result of script,
resizing, any one of a number of other factors.

Authors who need to be sure of the viewport should do so with load-event
or resize-event handlers.

Personally, as an author, I would like this to be clarified, and maybe
with some more research, we could figure out how do so in SVG 2.0 Core.

I hope this explanation is reasonable to you, and satisfies your comment.

Regards-
-Doug
Received on Saturday, 18 October 2008 03:35:41 GMT

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