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Re: [css3-images] Gradients feedback

From: Alan Gresley <alan@css-class.com>
Date: Mon, 30 Aug 2010 23:54:36 +1000
Message-ID: <4C7BB81C.4040804@css-class.com>
To: fantasai <fantasai.lists@inkedblade.net>
CC: "Tab Atkins Jr." <jackalmage@gmail.com>, Boris Zbarsky <bzbarsky@mit.edu>, www-style list <www-style@w3.org>
Alan Gresley wrote:
[snip]
>> The grayish band in the middle of the gradient is roughly the same as 
>> the midway point between yellow and white / black in the 
>> 3d-color-prism. It would actually be half the value in intensity.
[snip]

In other words, the midway point of this gradient,


<div style="background:-moz-linear-gradient(left, yellow, 
transparent)"></div>


is the same as this opaque color.


<div style="background:#808000;opacity:0.5;"></div>


I believe Boris is correct in the mathematics. Tab, regarding your 
thoughts on bugzilla [1].


   | Let me know if the term "sRGBA space" is nonsensical, and
   | I'll split out the color and opacity language explicitly


If I am somewhat correct in terminology and vectors, what we have in 
the gradient [2] is vector running from yellow to a midway point of 
the vector between white and black in sRGA space [3] [4] that reduces 
in opacity from 1 to 0, and I think operating like a scaler field.



1. <https://bugzilla.mozilla.org/show_bug.cgi?id=591600>
2. <http://en.wikipedia.org/wiki/Gradient_vector>
3. <http://en.wikipedia.org/wiki/SRGB>
4. <http://commons.wikimedia.org/wiki/File:RGB_color_solid_cube.png>
5. <http://en.wikipedia.org/wiki/Scalar_(mathematics)>



-- 
Alan http://css-class.com/

Armies Cannot Stop An Idea Whose Time Has Come. - Victor Hugo
Received on Monday, 30 August 2010 13:55:13 GMT

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