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Re: transparancy and RGB()

From: Chris Lilley <Chris.Lilley@sophia.inria.fr>
Date: Tue, 20 Aug 1996 18:12:24 +0200 (DST)
Message-Id: <9608201812.ZM24287@grommit.inria.fr>
To: Mike Wexler <mwexler@mv.us.adobe.com>, Chris Lilley <Chris.Lilley@sophia.inria.fr>
Cc: Chris Josephes <cpj1@winternet.com>, www-style@w3.org
On Aug 20,  8:22am, Mike Wexler wrote:
> Subject: Re: transparancy and RGB()
>
> > On Aug 14, 10:34pm, Chris Josephes wrote:
> >
> > > Has any thought been given to the idea of specifying varying levels of
> > > transparancy?  What about the idea of specifying the transparancy level
> > > directly in an RGB value, such as....
> > >
> > > p { background: rgb(20%,0%,0%,50%)} /* final value = transparancy level
*/

> Wouldn't it bet better to do
>     p { background: rgba(20%,0%,0%,50%) } /* fine value = alpha
(opaqueness)*/
>
> In the first example it is called rgb, but four values are supplied.
> Second, in computer graphics Red, Green, Blue, Alpha is much more common
> that Red, Green, Blue, Transparency.

Yes, that is a better idea.

> > That would be an interesting addition, and would fit well with image
formats
> > that support true variable transparency such as PNG and JPiG.
> Is JPiG a new format or just a mispelling of JPEG or JFIF?

JPiG is an attempt to add an alpha plane to JPEG JFIF. I am monitoring this
effort. So far they have some nice documentation and description on how it
might work, but no source code for a sample implementation.

I guess I should have mentioned TIFF as well, but few browsers support inline
TIFF.


-- 
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
Received on Tuesday, 20 August 1996 12:13:42 GMT

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