Re: HTML 3.2 PR color value syntax

Chris Lilley (Chris.Lilley@sophia.inria.fr)
Wed, 13 Nov 1996 22:27:28 +0100 (MET) 

Date: Wed, 13 Nov 1996 22:27:28 +0100 (MET)
From: Chris Lilley <Chris.Lilley@sophia.inria.fr>
Message-Id: <9611132227.ZM23003@grommit.inria.fr>
In-Reply-To: "David Perrell" <davidp@earthlink.net>
To: "David Perrell" <davidp@earthlink.net>, <www-html@w3.org>,
        "Chris Lilley" <chris@w3.org>,
Subject: Re: HTML 3.2 PR color value syntax

On Nov 13,  1:00pm, David Perrell wrote:

> Perhaps the above paragraph should be expanded to read:
>
> "The hexadecimal RGB (#rgb) notation can be any multiple of three
> digits. In the case where an output device has greater color resolution
> than the RGB values, the values are expanded by replicating digits. For
> example, the 12-bit value #fb0 is expanded to #ffbb00 for 24-bit
> output. In the case where an output device has less color resolution
> than the RGB values, the insignificant digits are ignored. For example,
> the 48-bit color value #ff12bb120012 is reduced to #ffbb00 for 24-bit
> output."

Although perhaps the example should be something like

#ff12bb830012 -> #ffbc00

> There was a suggestion a while ago to expand the CSS color triplet
> notation to include alpha channel in the color spec, as in
>
>            rgba(255, 127, 0, 63)
>
> This seems like a great idea. Why wait for CSS2?

It does seem like a great idea, and could work well with background
images, negative margins, etc. The rgba notation is good. As to whether
it makes it into CSS1 or a later spec, that is not my call. I suspect
the whole spec would need a good going over to see what happens if
things can now be semi-opaque.


> In this case it should be possible to mix value types in a triplet or
> quadlet(?) so that the above could be:
>
>            rgba(255, 127, 0, 25%)

Why? It isn't clear why being able to say

rgba (36, #bc, 0.7, 112%) is very valuable.


-- 
Chris Lilley, W3C                          [ http://www.w3.org/ ]
Graphics and Fonts Guy            The World Wide Web Consortium
http://www.w3.org/people/chris/              INRIA,  Projet W3C
chris@w3.org                       2004 Rt des Lucioles / BP 93
+33 93 65 79 87            06902 Sophia Antipolis Cedex, France