Re: [css-backgrounds] Clarification proposal for border colors

First, I must say thanks to everyone that commented on the issue.

There seems to be some agreement towards suggesting a non-normative
algorithm, which could be referenced by spec-ing lighten()/darken() in
Color.

I see the whole subject taking 3 steps, as follow:
a) make it explicit the black case;
b) defining a general algorithm (that may be a bit tricky);
c) spec-ing lighten()/darken() in Color.


The reason why I think it makes sense to make the black border case
explicit is that 3 different web engines (WebKit, Blink, Servo) got it
wrong. I would say that is strong evidence that the spec may be unclear.

As such, Iıve opened the merge request to add to the css-backgrounds spec:
https://github.com/w3c/csswg-drafts/pull/52



Adenilson


>On 14/09/15 19:15, Simon Fraser wrote:
>>> On Sep 14, 2015, at 8:24 AM, Adenilson Cavalcanti
>>> <a.cavalcanti@samsung.com <mailto:a.cavalcanti@samsung.com>> wrote:
>>>
>>> The border style spec
>>> (http://dev.w3.org/csswg/css-backgrounds/#the-border-style
>>> <http://dev.w3..org/csswg/css-backgrounds/#the-border-style>) is
>>> implemented in probably all browsers and has being around for quite a
>>> long time.
>>>
>>> I observed that the description of the behavior for 'grooveı value
>>> (and the complementary 'ridge') is a bit vague about what the UA is
>>> supposed to do.
>>>
>>> Quoting: "Looks as if it were carved in the canvas. (This is typically
>>> achieved by creating a ³shadow² from two colors that are slightly
>>> lighter and darker than the Œborder-colorı.)"
>>>
>>> I think the 'two colors' part could be more descriptive.
>>>
>>> What if we changed it to be clearer and write something like:
>>> ³The light color should be a percentage of the darker color, between
>>> 20% to 50% of its absolute value. And the darker color a percentage in
>>> a range of 70% to 90% of border color."
>>>
>>> Another issue is that the behavior for black border could be explicit.
>>> I think we could follow up with: "In case the border color is black, a
>>> shade of gray must be used as the lighter color.²
>
>Iım in favor of suggesting a non-normative but well-defined algorithm in
>the spec.
>
>> I think a good way to spec this would be to spec lighten() and darken()
>> color functions, which you could then refer to in the groove/inset
>> border spec.
>
>Would color(Š lightness(Š)) from
>https://drafts.csswg.org/css-color/#modifying-colors work?
>
>-- 
>Simon Sapin
>

Received on Monday, 21 September 2015 17:51:11 UTC