W3C home > Mailing lists > Public > www-style@w3.org > August 2009

Re: Gradient syntax proposal

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Mon, 17 Aug 2009 20:58:53 -0500
Message-ID: <dd0fbad0908171858l5014f5adu734900cc9c6af0ef@mail.gmail.com>
To: fantasai <fantasai.lists@inkedblade.net>
Cc: www-style@w3.org
On Mon, Aug 17, 2009 at 5:34 PM, fantasai<fantasai.lists@inkedblade.net> wrote:
> Tab Atkins Jr. wrote:
>>
>> On Mon, Aug 17, 2009 at 3:54 PM, fantasai<fantasai.lists@inkedblade.net>
>> wrote:
>>>
>>> Brad Kemper wrote:
>>>>
>>>> On Aug 17, 2009, at 11:00 AM, fantasai <fantasai.lists@inkedblade.net>
>>>> wrote:
>>>>
>>>>> I would prefer restricting stops to percentages. The swapping effect
>>>>> is confusing, and I don't see any reason you'd /need/ to use lengths
>>>>> when you can specify the length of the overall gradient already.
>>>>
>>>> I can think of plenty of situations where  I'd want the whole gradient
>>>> to
>>>> be a fixed distance, regardless of box size, and regardless of angle.
>>>> I'd
>>>> like to be able to set that in a simple grammar, using color-stops only.
>>>> It's not nearly as simple if the angle is not a multiple of 90, and I
>>>> have
>>>> to use bg-position.
>>>
>>> This is not simple?
>>>
>>>  linear-gradient(top left 135deg 200px / red, white, blue)
>>>  /* linear gradient from top left corner angled at 135deg going for 200px
>>>    transitioning from red to white to blue */
>>
>> That requires an *additional* argument to the angle construction.
>> It's equally easy to do:
>>
>> linear-gradient(135deg / red, white, blue 200px)
>
> Which requires an additional argument to the last color construction. :)

Ah, but it's an argument that's already included in the syntax.

> Is the 200px offset from the beginning of the gradient or from the
> last color stop? I'm not totally clear on this. (I find it easier
> to think of the entire gradient being 200px long and then filling
> in the color stops than positioning the last color stop and then
> filling in the color stops backwards from there.)

All color-stop lengths and % measure from the beginning.

>> (You probably meant an angle other than 135deg, btw.  That points up
>> into the top-left, and would currently result in a pure-blue gradient
>> as the starting and ending points are identical.)
>
> Heh, okay. I wasn't sure which direction 0deg was pointing.
> For several other properties (e.g. image-orientation) it's up.

Well, not really.  The angle in image-orientation describes a
rotation, not a direction.  It just reuses SVG's definition of
positive angles meaning a CW rotation, which is a little confusing.
But doing *anything* other than 0deg=East, 90deg=North for actual
directional angles would be extremely confusing as well.

I'll make it explicit.

~TJ
Received on Tuesday, 18 August 2009 01:59:48 GMT

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