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RE: [SVGMobile12] event aliasing

From: Jon Ferraiolo <jonf@adobe.com>
Date: Mon, 3 Apr 2006 15:16:59 -0700
Message-ID: <6ECA24BE410D994496A2AE995367C5C8917EBD@namail3.corp.adobe.com>
To: "Bjoern Hoehrmann" <derhoermi@gmx.net>
Cc: <www-svg@w3.org>


Bjoern,
Thanks for the background information on gradients.

I don't remember the rationale behind the WG discussion on disallowing percentages on gradients with userSpaceOnUse in Tiny 1.2. It seems to me that it would not be that hard for a Tiny UA to support percentages for userSpaceOnUse for gradient stops since Tiny 1.2 has been purposefully designed so that there is only one viewport (i.e., the outermost svg:svg). However, I repeat again that I don't remember how the discussion went within the working group, so I might be missing something in my analysis, but based on what I know right now, it seems to me that Tiny 1.2 should support the same features for 'offset' as Full 1.1 in a fully compatible way or support a fully compatible subset for 'offset'. One possible subset approach would be to disallow in Tiny 1.2 any content which uses percentage values in conjunction with userSpaceOnUse. While maybe this isn't the optimal solution, I think it does allow Tiny 1.2 to support most of the SVG content that uses gradients, where the content either uses objectBoundingBox (with fractions or percentages) or userSpaceOnUse (with numbers but not percentages).

Jon

-----Original Message-----
From: Bjoern Hoehrmann [mailto:derhoermi@gmx.net] 
Sent: Monday, April 03, 2006 2:55 PM
To: Jon Ferraiolo
Cc: www-svg@w3.org
Subject: Re: [SVGMobile12] event aliasing

* Jon Ferraiolo wrote:
>I think you will agree that just because the SVG WG breaks compatibility
>with the past in one area as justification for breaking it in another.

I think that once you start making changes that affect conformance you
cannot reject proposals for changes that affect conformance simply be-
cause they affect conformance. I would even suggest to assume that the
reviewer considered this to some extend.

>Regarding the changes for gradients, I was not aware that there were
>incompatible changes and, if you are correct, then I would really like
>to know why such incompatible changes were made, *especially* if there
>is actual content that relies on the old behavior.

The default values are percentages which SVG Tiny 1.2 does not support
anywhere but height/width on the svg element and maybe rgb(). I've
pointed this problem out a year ago in

  http://lists.w3.org/Archives/Public/www-svg/2005Mar/0051.html

Not supporting percentages is a very bad idea in cases like <stop
offset=... />, but well... Here specifically the percentages are
relative to the viewport, I've so far assumed that the changes were
made due to performance considerations in certain implementations.
I've asked in

  http://lists.w3.org/Archives/Public/www-svg/2006Mar/0147.html

to explain these changes better.
-- 
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Received on Monday, 3 April 2006 22:17:24 GMT

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