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[css4 color] gray() issue 2 - possible errors

From: Alan Gresley <alan@css-class.com>
Date: Sat, 11 Jan 2014 22:50:59 +1100
Message-ID: <52D13023.8020203@css-class.com>
To: CSS 3 W3C Group <www-style@w3.org>
Hello all,

I believe there is an error with 'issue 2' in 6 [1] of CSS4:

   | Issue 2: gray() should have a keyword arg that opts
   | it into smarter modes.

Should *arg* be *argument*?

Also there is the following:

   | #757575 is the gray that lives exactly between
   | white and black, in contrast-ratio space.

Should #757575 be #797979 or #808080? If this was to become non 
normative text, you would have to further explain contrast ratio and why 
#757575 is not halfway.

Also there is the following:

   | Taking 0% to be black, 100% to be white,
   | and 50% to be #757575, you convert between
   | contrast-ratio space and luminance space with
   | L = 21^p, then find the gray with that luminance.

Why is there 'contrast-ratio space' instead of just 'contrast ratio'? 
Would contrast-ratio depth be more appropriate since the contrast ratio 
is relating to color depth (deep color)? It's not tied to a particular 
color-space but more to do with the contrast ratio of a display device.

Should 'luminance space' be replace with 'relative luminance' [2]? You 
can have relative luminance in colorimetric spaces and I believe this is 
what these words are attempting to be convey.

1. http://dev.w3.org/csswg/css-color/#grays
2. http://en.wikipedia.org/wiki/Luminance_%28relative%29


P.S. Though off-topic for this list, the color table for 4.2 Examples 
of HSL colors and 5.2 Examples of HWB Colors are broken. See attached 
screenshot 'hsl.png'. It looks better with .color-table {width: 300%;}

(image/png attachment: hsl.png)

Received on Saturday, 11 January 2014 11:51:27 UTC

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