W3C home > Mailing lists > Public > www-style@w3.org > November 2012

Re: [css4-images] One color stop should now be allowed

From: Dirk Schulze <dschulze@adobe.com>
Date: Mon, 5 Nov 2012 15:49:00 -0800
To: "Tab Atkins Jr." <jackalmage@gmail.com>
CC: Lea Verou <lea@w3.org>, www-style list <www-style@w3.org>
Message-ID: <812CBC2D-0DBC-415B-B2B1-CA0811F5D14B@adobe.com>

On Nov 5, 2012, at 3:33 PM, Tab Atkins Jr. <jackalmage@gmail.com> wrote:

> On Mon, Nov 5, 2012 at 11:05 AM, Lea Verou <lea@w3.org> wrote:
>> Since we can now have two positions per color stop [1], which is equivalent
>> to two color stops with the older syntax, gradients should permit one color
>> stop only. Grammar-wise, it's only a matter of converting a few +s to *s.
>> In case the only color stop doesn't include two positions, it could be
>> defined as equivalent to having 0% 100%. Yes, this is essentially identical
>> to using image(color), but:
>> 1. There is no serious reason to disallow degenerate applications of any CSS
>> feature and few other CSS features do.
>> 2. It ensures consistency and matches author expectations.
>> 3. Good educational value: People who use editors that live update will be
>> able to see what they're doing before they even type the second color.
>> Instant feedback is an age-old UI principle and syntax is the UI of the
>> language.
>> 4. It's trivial to implement.
>> [1]: http://www.w3.org/TR/css4-images/#color-stop-syntax
> While I don't have anything particularly *against* such a thing (as
> you point out, it's trivial to handle), is there any good reason to do
> it?  A gradient with a single color isn't a gradient at all.
> Why do you think it matches author expectations to allow a single
> color?  ("Because they told me so" is fine, though I'd like more
> detail about what confused them.)
> Allowing live editors to provide feedback as soon as possible is a
> decent reason (part of why CSS allows so much to be omitted in the
> first place), but before you add the second color, you don't even know
> what the gradient *looks* like.
> I imagine that if there was only a single color-stop, it would just
> compute itself to "color 0% 100%"?
Correct. It would be the same as if just a color was specified. This is actually in use on content with SVG gradients (even if I don't like it and it is done because of silly reasons). SVG gradients specify what to do for a single stop color.


> ~TJ
Received on Monday, 5 November 2012 23:49:26 UTC

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