[cairo] order of circles in radial gradients

[Robert O'Callahan]

On Wed, Aug 5, 2009 at 7:27 PM, Chris Wilson <chris at chris-wilson.co.uk>wrote:

> On Wed, 2009-08-05 at 16:29 +1200, Robert O'Callahan wrote:
> > The Quartz backend treats the circles symmetrically, so it draws the
> > gradient moving inward from the start circle to the end circle, with
> > the first stop color filling outside the start circle and the last
> > stop color filling inside the end circleThis seems a little more
> > logical to me.
> >
> > What is the correct behaviour?
>
> As you describe for Quartz, start colour outside with a ramp to end
> colour inside. Unsurprisingly, this is also the expected behaviour for
> PDF. I've recently fixed a bug in pixman for this issue:
>
> commit 20d2df03059d6a5941464d80e81e8116ebf4dbfe
> Author: Chris Wilson <chris at chris-wilson.co.uk>
> Date:   Thu Jul 23 19:08:40 2009 +0100
>
>    Fix inversion of radial gradients when r2 > r1
>
>    Fixes: Bug 22908 -- Invalid output of radial gradient
>    http://bugs.freedesktop.org/show_bug.cgi?id=22908
>
> And I extended the radial gradient test case in cairo to cover these
> conditions. I'd appreciate it if you could check the test case to make
> sure I've not missed a condition, and check the output of a recent
> pixman.
>

Thanks, the test looks good to me, but I'll probably wait until Mozilla's
cairo is updated to test it.

Rob
-- 
"He was pierced for our transgressions, he was crushed for our iniquities;
the punishment that brought us peace was upon him, and by his wounds we are
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own way; and the LORD has laid on him the iniquity of us all." [Isaiah
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