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RE: CSS3 module: Color

From: Jonathan Stanley <jon@asciigrackle.eclipse.co.uk>
Date: Wed, 26 Feb 2003 21:58:40 -0500 (EST)
Message-ID: <046d01c2de0b$af1d3a50$702698d5@meugh>
To: <www-style@w3.org>



Hi

Had a good little read from a users point of view, and quite excited about
some of the things it'll bring (though how soon browsers support it is a
slightly different matter :( )

Anyway, I see within the RGB(A) model, the valid ranges are defined in
section 4.2.2:

---
em { color: rgb(255,0,0) }      /* integer range 0 - 255 */
em { color: rgba(255,0,0,1)     /* the same, with explicit opacity of 1 */
em { color: rgb(100%,0%,0%) }   /* float range 0.0% - 100.0% */
em { color: rgba(100%,0%,0%,1) } /* the same, with explicit opacity of 1 */
---

If R, G and B can have values from 0.0% to 100.0% percent, then why is A,
alpha, so limited within the bounds of 0.0 to 1.0, equivanlent to 0% to 100%
in 10% steps. So perhaps a range from 0.00 to 1.00? Or alternatively, why
aren't percentages used for that (alpha) value too?

Should opacity keywords be available? eg:

transparent: alpha = 0
very-transparent: alpha = 0.25
semi-transparent(/semi-opaque?): alpha = 0.5
very-opaque: alpha = 0.75
opaque: alpha = 1

There also isn't bounds for values when using the HSL(A) colour model, other
than definition of hue, that 0 = 360, no definition of how negative values
are handled, eg:

* { color: hsl(-240, 100%, 50%) }

... or going round "more than once" in the colour wheel:

* { color: hsl(840, 100%, 50%) }

Then the "currentColor" property which is treated as "inherit" at parse
time, would be better hypenated? That is: "current-color"

Thanks. :)
Received on Thursday, 27 February 2003 05:37:10 GMT

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