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Re: [Rendering Order] Some early feedback

From: Doug Schepers <schepers@w3.org>
Date: Mon, 26 Oct 2009 12:29:20 -0400
Message-ID: <4AE5CE60.9000303@w3.org>
To: Jeff Schiller <codedread@gmail.com>
CC: Jonathan Watt <jwatt@jwatt.org>, www-svg <www-svg@w3.org>
Hi, Jeff-

Jeff Schiller wrote (on 10/26/09 11:47 AM):
> On Mon, Oct 26, 2009 at 5:44 AM, Jonathan Watt<jwatt@jwatt.org>  wrote:
>>  To me the most compelling reason for z-index type functionality is to avoid the
>>  problem of images and sub-documents (e.g. iframe in foreignObject) from having
>>  to be reloaded due to them being removed temporarily from the DOM to reposition
>>  them somewhere else.
> I'm not a DOM expert, especially when it comes to load events, things
> like that - but it seems to me that this is the main reason people
> think they need the ability to arbitrarily order the document.  My own
> thoughts on this are:  why does the image need to be reloaded when an
> insertBefore() has been done?  Could additional requirements be added
> to the DOM to change this behavior upon insertBefore()?
> i.e. "If the node being inserted into the DOM already exists in that
> DOM, the user agent must only reposition the node in the DOM, the user
> agent must not reload the contents or ..."
> If this has the potential to break a whole lot of existing web content
> (as I now suspect it does), then could a new method be added into the
> core DOM? i.e. moveElement() that has the same function signature as
> insertBefore()?

This may solve the script case (though I'm afraid it might introduce 
other complexities), but it doesn't solve the declarative case.

> Several members of the SVG IG were chatting about this at SVG Open
> (Ruud, Wade, myself).  At the time we thought z-index (or something
> equivalent) breaks the elegance of SVG for the reasons that Ruud
> stated above.

Having to use script to accomplish this also breaks the elegance of SVG, 
for static or declarative documents.

>  We were originally thinking about a new method for
> moving elements within a DOM but I wasn't even sure this was required
> since I was not familiar with the requirements on UAs to reload
> content when insertBefore() had been called.

It's an option we should consider.

-Doug Schepers
W3C Team Contact, SVG and WebApps WGs
Received on Monday, 26 October 2009 16:29:26 UTC

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