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Re: W3C 'CSS3 module: Color' Working Draft dated 19th February 2002

From: fantasai <fantasai@escape.com>
Date: Tue, 26 Mar 2002 02:00:39 -0500
Message-ID: <3CA01C97.B802BB26@escape.com>
To: www-style@w3.org
Tantek Çelik wrote:
>
> text-decoration-opacity

I think text-decoration can be fairly grouped with text, especially since it
doesn't have a separate color property, either. (And if there were separate
opacity properties, border and outline opacity could have an initial value of
 <foreground-opacity>, just as border-color has an initial value of <color>).

> It is much simpler to introduce 2 new color value types which can then be
> used with all properties that specify a color, rather than add 5-9 new
> properties.
> 
> In addition, the new color value types permit controlling the opacity of
> these pieces of elements independently of elements' children, which the
> opacity property does affect.

Which shows the fundamental problem with declaring rgba and hsla the
solution to separating background and foreground opacity.

Suppose I have a <div>. I want the the <div>'s background to be translucent,
but it's text should be opaque so it's easily readable. It's a reasonable
request, no?

<div class="sidebar">
  <p>Paragraph text.... <a href="file.html">Link</a>... So <strong>DON"T
     FORGET...</strong> etc.
  </p>
</div>

Your suggestion would be to set the background as a transparent color. Thus:

  .sidebar {
      background: rgba(255, 255, 0, .5);
  }

Which works fine, except I also happen to have these rules in effect:

   :link, :visited {
      background: #FFBB00;
      color: #000033;
   }

   strong {
     background: #FF0000;
     color: #000000;
   }

So the background on the link and emphasized notice is opaque. This is not
according to my design, and IMO, it looks bad. So now I have to write separate
rules for any elements in a sidebar, adjusting the background color's opacity
accordingly. This isn't much of a problem if I only have to deal with sidebars,
and only with links and strong emphasis. However, using this approach with a
complicated stylesheet and a large variety of elements is inelegant and prone
to mistakes.
Received on Tuesday, 26 March 2002 01:57:23 GMT

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