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Re: Use Cases for The <canvas> Element

From: Lachlan Hunt <lachlan.hunt@lachy.id.au>
Date: Mon, 30 Jul 2007 12:29:12 +1000
Message-ID: <46AD4CF8.8090607@lachy.id.au>
To: Sander Tekelenburg <st@isoc.nl>
CC: public-html@w3.org

Sander Tekelenburg wrote:
> At 05:42 +1000 UTC, on 2007-07-30, Lachlan Hunt wrote:
>> Philip Taylor (Webmaster) wrote:
>>> "examples where dynamic and interactive graphics have been used
>>> in the past" demonstrate the need for "dynamic and interactive
>>> graphics".  They do /not/ demonstrate a need for "canvas",
>>> which is (one of many possible) solutions.
>> That's technically true, but in this case, we already have at least 3
>> native implementations in Firefox, Opera and Safari, and a working
>> scripted implementation for IE.
> You seem to be saying that when <x> is implemented in certain UAs, there's no
> longer a need to demonstrate the need for <x> -- that that need applies only
> to elements/attributes that are not implemented in UAs.

No, that's not what I said.  In fact, the point of my email was to 
demonstrate the need for <canvas>.  I just skipped the step going from 
defining the problem to considering and evaluating alternative solutions.

As James pointed out, one of the only alternatives was overloading img, 
but that couldn't work because the implementation of canvas and img are 
fundamentally different.  As we know from experience with object, 
overloading elements with too much functionality increases the 
complexity of the implementation and increases the chance of bugs.

> As hard as I try, I don't see how to interpret that as anything else then "UA
> vendors will do what they want, the rest of you will just have to play by
> some rules we set for you".

It is unfortunate that Apple went ahead and implemented it without much 
public discussion during its development, but we can't change the past.

>> Plus, as my examples showed, it's already being widely used.
> If that's an argument, then clearly the need for native SVG is stronger than
> that for <canvas>, as Karl listed more examples.

Yes, SVG in HTML has been discussed as a possibility in the past on the 
whatwg mailing list.  It's just not particularly easy considering issues 
like parsing requirements, namespaces, etc.

Lachlan Hunt
Received on Monday, 30 July 2007 02:29:29 UTC

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