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Re: [css3-images] July F2F minutes comment regarding SVG and non-opaque colors

From: Alan Gresley <alan@css-class.com>
Date: Fri, 19 Aug 2011 19:33:23 +1000
Message-ID: <4E4E2DE3.9000105@css-class.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
CC: Cameron McCormack <cam@mcc.id.au>, Brian Manthos <brianman@microsoft.com>, "www-style@w3.org" <www-style@w3.org>
On 19/08/2011 8:45 AM, Tab Atkins Jr. wrote:
> On Thu, Aug 18, 2011 at 3:36 PM, Cameron McCormack<cam@mcc.id.au>  wrote:
>> It's true that SVG 1.1's<color>  definition doesn't technically allow rgba()
>> colours, but it would be interesting to see what implementations do with it
>> currently to know whether this is compatible with Image Values' definitions.
>>   Also whether this behaviour is the same as an SVG gradient where some stops
>> have non-zero stop-opacity property values.
> I can't immediately test other browsers, but Chrome simply ignores the
> transparency of the color, while Firefox does the transition in
> post-multiplied space (same as they currently do for
> linear-gradient()).
> ~TJ

Both Chrome and Safari 5.1 seem to interpolate rbga in pre-multiplied 
space. Gecko, Opera 11.50, 1E9 and IE10 preview 2  interpolate the below 
gradient in post-multiplied space.

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1 plus MathML 2.0 plus SVG 
1.1//EN" "http://www.w3.org/2002/04/xhtml-math-svg/xhtml-math-svg.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" 
<style type="text/css">
   svg {background: black; width: 100px; height: 100px;}


<svg:linearGradient id="gradient" gradientUnits="userSpaceOnUse" x1="0" 
y1="100" x2="100" y2="0">
   <svg:stop offset="0" style="stop-color:rgba(255,255,0,1)"/>
   <svg:stop offset="1" style="stop-color:rgba(255,0,255,0)"/>
<svg:path fill="url(#gradient)" d="M0,0v100h100V0H0z" />



Alan Gresley
Received on Friday, 19 August 2011 09:33:31 UTC

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