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

From: Chris Lilley <chris@w3.org>
Date: Wed, 8 May 2002 23:46:12 +0200
Message-ID: <2011025163.20020508234612@w3.org>
To: www-style@w3.org, ewexler@stickdog.com
On Wednesday, May 8, 2002, 9:46:09 AM, ewexler wrote:


esc> 4.2.4 "HSL color values"


esc> "CSS3 adds numerical Hue Saturation Lightness (HSL)"

esc> Change to "CSS3 adds numerical hue-saturation-lightness (HSL)".

It is written like that to introduce the acronym HSL, and also to
indicate that subsequent mentions of Hue refer to the definition from
HSL rather than (for example) the definitions of hue from Munsell or
CIE or whatever.


esc> "RGB is hardware-oriented: it reflects the use of CRT's"

esc> Add an ending period.

Yes. Or perhaps reword - on reflection, its not so much hardware
oriented as physics oriented.


esc> "RGB is oriented to light rather than (what people find more intuitive) 
esc> print. For instance, yellow is red+green in RGB."

esc> This is redundant given the following and should be removed.

Yes.

esc> "RGB is non-intuitive. People can learn how to use RGB, but actually by 
esc> internalizing how to translate Hue, Saturation and Lightness, or 
esc> something similar, to RGB."

esc> Change "H" to "h", "S" to "s", and "L" to "l".  These are not proper nouns.

They are particular rather than generic definitions. Lightness, in
this spec, means lightness as defined in HSL as opposed to (for
example) lightness as defined by the CIE.


esc> "Hue is represented as an angle of the color circle (i.e. the rainbow 
esc> represented in a circle)."

esc> Add "This angle is so typically measured in degrees that the unit is 
esc> implicit in CSS; syntactically, only a <number> is given.".

Good point, and I agree both that it is an angle and that an angular
unit is not useful here. Further, the option to use radians or grads would
offer nothing but confusion and complexity.

esc> "By definition Red=0=360, and the other colors are spread around the 
esc> circle, so Green=120, Blue=240, etc. Saturation and Lightness are 
esc> represented as percentages."

esc> Change the capitals to lowercase.

I agree here.


esc> "100% is full saturation, and 0% is a shade of grey. 0% lightness is 
esc> black, 100% lightness is white, and 50% lightness is 'normal' "

esc> Add a final period.  Then add "A value of " to the beginning of each 
esc> sentence because digits are not to start a sentence.

Yes. And perhaps "normal" is not so clear, as well.


esc> 4.4.1 "CSS2 User preferences for colors"


esc> "The computed value of a System Color keyword value is the keyword 
esc> itself."

esc> Why is this?

So that what is inherited means something, and so that DOM calls get
useful information. The actual RGB values will vary according to OS
and user preference.

esc> "Most desktop user agents allow the user to choose the default colors 
esc> for hyperlinks to be rendered in their various states. The following 
esc> system colors permit an author to explicitly style their hyperlinks in 
esc> accordance with those preferences."

esc> Change both occurences of "hyperlinks" to "hyperlink anchors".  After 
esc> the second occurrence add "and other elements.".

Good suggestion.

esc> "The color names are camel-cased"

esc> Change to "The color names, though case-insensitive, are presented 
esc> here in mixed case"

That is clearer, but the term camel  case should still be introduced, I feel.

esc> 4.5. "Notes on using colors"

esc> "If you use a background image or set the background color, then be 
esc> sure to set the various text colors as well."

esc> Change to "When setting a background image or background color, set 
esc> the text color in the same rule set and at the same weight (e.g., 
esc> '!important').  When setting a text color, set the background in the same 
esc> rule set and at the same weight."

I agree that is more precise, though it is perhaps too prescriptive.

esc> 6. "Profiles"

esc> "CSS level 1" ... 
esc> "Excludes 
esc> 'opacity' property
esc> 'color-profile' property
esc> 'rendering-intent' property
esc> @color-profile rule
esc> RGBA color values
esc> HSL and HSLA color values
esc> X11 color keywords
esc> CSS2 UI Colors
esc> CSS3 Hyperlink Colors
esc> 'transparent' color value
esc> 'flavor' color value"

esc> In fact, CSS1 accepts any identifier as a color value.  While CSS1 did 
esc> not specify semantics of particular color keywords, it did not constrain 
esc> them, either.  A CSS1 implementation written at this time could 
esc> legitimately incorporate the X11 color keywords, CSS2 UI colors, CSS3 
esc> hyperlink colors, and the 'flavor' color keyword and offer the associated 
esc> functionality.  Nothing in the CSS1 specification prohibits this.  It would 
esc> be best to move those four items out of "Excludes" and into a note.-- 
esc> Etan Wexler <mailto:ewexler@stickdog.com>

Hmm, good point. Do we really want to propagate the vagueness of this
point of the specification, however? I guess it depends on whether the
CSS1 profile is supposed to represent what CSS1 specified the meaning
of, or what it syntactically allowed.

Thanks for your careful review! Much appreciated.

-- 
 Chris                            mailto:chris@w3.org
Received on Wednesday, 8 May 2002 17:46:21 GMT

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