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Re: radial-gradient() proposal

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Fri, 6 Nov 2009 15:06:35 -0800
Message-ID: <dd0fbad0911061506l2cd0eb34q27d3cc285e0be769@mail.gmail.com>
To: Brendan Kenny <bckenny@gmail.com>
Cc: fantasai <fantasai.lists@inkedblade.net>, Brad Kemper <brad.kemper@gmail.com>, Simon Fraser <smfr@me.com>, www-style list <www-style@w3.org>
On Fri, Nov 6, 2009 at 2:57 PM, Brendan Kenny <bckenny@gmail.com> wrote:
> I sketched a quick diagram that might help (with apologies for the lengthy url)
>
> http://lh6.ggpht.com/_K6wA3xN79Qs/SvSmsPplRKI/AAAAAAAAAcc/QtG6Jt4I-ys/s800/gradient-angle.png

If anyone was unclear on exactly what my "starting-point is the point
on the gradient-line where a line drawn perpendicular..." language
meant, there you go.

(Mind if I steal that image?  It may be useful to put into the spec,
since it illustrates *precisely* the language I'm using.)

> Note that this is the default behavior for Illustrator gradients when
> an angle is given but not end points: it assumes you want to
> completely fill the selected shape and that the color stops at 0 and
> 100% should occur at the last pixels possible. That behavior is
> equivalent to Tab's recommendation for the <angle> parameter, as long
> as no background position is specified, and what I think one would
> expect if just an angle was specified (ignoring for now the formula
> for specifying how to select a "starting" corner based on the angle).

Well, the default corner would be pretty much in all cases what you'd
select with that type of behavior.

> Incidentally, if you change the Illustrator artboard to have its
> origin in the top left and have y increase downwards, selecting a
> linear gradient with angle 60 degrees puts the 100% colorstop 60
> degrees clockwise from 0 degrees, exactly as you'd expect if you think
> of the angle as rotating a direction arrow in screen space. For what
> that's worth.

I'm beginning a survey now, and we'll be expanding it this weekend, to
see what makes the most sense for people.  No sense arguing when we
can get hard data.  ^_^  So moratorium on discussing angles?

~TJ
Received on Friday, 6 November 2009 23:07:30 GMT

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