W3C home > Mailing lists > Public > www-style@w3.org > May 2004

Re: Opacities

From: Ernest Cline <ernestcline@mindspring.com>
Date: Sun, 16 May 2004 15:45:54 -0400
Message-ID: <410-220045016194554796@mindspring.com>
To: "Richard York" <richy@smilingsouls.net>, www-style@w3.org




> [Original Message]
> From: Richard York <richy@smilingsouls.net>
>
> ... what about jpeg, the most common image format. If a browser has 
> the ability to do opacity on the entire element, then it should also be 
> able to separate it between foreground and background, who wants
> to use large bulky PNG files when it could be done with a tiny jpeg
> and opacity via the browser. Non-support of separating the opacity
> will result in hacks using absolute positioning and the like to get
> background opacity but not foreground opacity.

Well then use JPG2000 files.  They do include opacity and work well
with the types of files for which JPG produces smaller files than does
PNG.  Support for the JPG2000 format should be widespread well
before support for CSS background/forground opacity properties
could be widespread.

> Personally I think this is a feature that will continue to be requested 
> many times. It really isn't a pricey addition anyway since opacity is 
> already supported via the opacity property. The convenience and
> consumer demand of such a feature out-weighs any perceived
> bloatedness (if that's a word) it might bring IMHO. By the same token
> not supporting it will result in unnecessary hacks even if the effect
> can be done with PNG, SVG or any other graphic format.

In any case there will exist a CSS hack to do this once the Generated
Content module enters the CR stage.

#foo::outside {
  display:block;
  background-image:url(bar.jpg);
  opacity:0.8;
}

without having to add a property like so:

#foo {
  background-image:url(bar.jpg);
  background-opacity: 0.8;
}

I'd much rather have the hack be used on those few occasions where
it will be useful than to have to carry an extra pait of properties on
every element.
Received on Sunday, 16 May 2004 15:46:07 GMT

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