W3C home > Mailing lists > Public > www-style@w3.org > February 2003

Re: Color module comments (WD-css3-color-20020418)

From: Tantek Çelik <tantek@cs.stanford.edu>
Date: Fri, 07 Feb 2003 22:21:33 -0800
To: <ewexler@stickdog.com>, <www-style@w3.org>
Message-ID: <BA69D948.20605%tantek@cs.stanford.edu>

On 5/8/02 12:46 AM, "ewexler@stickdog.com" <ewexler@stickdog.com> wrote:

> 4.5. "Notes on using colors"
> 
> "If you use a background image or set the background color, then be
> sure to set the various text colors as well."
> 
> Change to "When setting a background image or background color, set
> the text color in the same rule set and at the same weight (e.g.,
> '!important').  When setting a text color, set the background in the same
> rule set and at the same weight."

I think I will replace this entire subsection with the proper reference to

 http://www.w3.org/TR/WAI-WEBCONTENT


> 6. "Profiles"
> 
> "CSS level 1" ...
> "Excludes 
> 'opacity' property
> 'color-profile' property
> 'rendering-intent' property
> @color-profile rule
> RGBA color values
> HSL and HSLA color values
> X11 color keywords
> CSS2 UI Colors
> CSS3 Hyperlink Colors
> 'transparent' color value
> 'flavor' color value"
> 
> In fact, CSS1 accepts any identifier as a color value.  While CSS1 did
> not specify semantics of particular color keywords, it did not constrain
> them, either. 

Really?  Well, let's take a quick look:

 http://www.w3.org/TR/REC-CSS1#color-units

"
A color is a either a keyword or a numerical RGB specification.

The suggested list of keyword color names is: aqua, black, blue, fuchsia,
gray, green, lime, maroon, navy, olive, purple, red, silver, teal, white,
and yellow. These 16 colors are taken from the Windows VGA palette, and
their RGB values are not defined in this specification.
"

The use of "suggested" seems to imply that there is no requirement that user
agents support this list.  It reads as a "may" requirement.

As far as the keywords themselves, there are only 16 _known_ color keywords
as far as CSS1 is concerned.  Any other keywords would have to be considered
unknown since they are undefined.

Section 7.1

 http://www.w3.org/TR/REC-CSS1#forward-compatible-parsing

States:

"illegal values, or values with illegal parts, are treated as if the
declaration weren't there at all"

Technically, an "unknown" value is not the same as an "illegal" value, and
thus your interpretation does seem allowable if a stretch.

> A CSS1 implementation written at this time could
> legitimately incorporate the X11 color keywords, CSS2 UI colors, CSS3
> hyperlink colors, and the 'flavor' color keyword and offer the associated
> functionality.  Nothing in the CSS1 specification prohibits this.  It would
> be best to move those four items out of "Excludes" and into a note.--

However, I do not think that this was the intent of the CSS1 specification
(perhaps the authors wish to clarify), nor does the CSS validator.

Thus I think it is preferable to reflect what was intended, and errata the
letter of CSS1 to reflect what was intended.  Of course Bert and/or Hċkon
could reply to this message with a differing statement of what was intended.

Tantek
Received on Saturday, 8 February 2003 01:09:16 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 27 April 2009 13:54:19 GMT