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Re: Gradient syntax proposal

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Fri, 14 Aug 2009 09:46:36 -0500
Message-ID: <dd0fbad0908140746t6fcd2886r42a8c0449ed42e79@mail.gmail.com>
To: Øyvind Stenhaug <oyvinds@opera.com>
Cc: www-style@w3.org
On Fri, Aug 14, 2009 at 6:33 AM, Øyvind Stenhaug<oyvinds@opera.com> wrote:
> On Fri, 14 Aug 2009 01:35:56 +0200, Tab Atkins Jr. <jackalmage@gmail.com>
> wrote:
>
>> Just linear gradients for now:
>>
>>
>> http://www.xanthir.com/document/document.php?id=d65df9d10442ef96c2dfe5e1d7bbebf7aa42f2bcf24e68fc3777c4b484fa8a4ce55fed2189cac20ccad8686127f4c08917c4ca8b7614e9f89c2a950ec083a9c6
>
> Maybe the coordinate system for angles was intentionally chosen this way
> because of consistency with Photoshop or something (I'm not familiar with
> it), but I thought I'd point out that it differs from CSS transforms (where
> positive angles are clockwise).
>
> (The proposal doesn't specify a coordinate system, so I inferred it from
> what would make most sense given the pairings of angle intervals and corner
> starting points.)

Damns, really?  That's no good.  I don't remember enough of my linear
algebra to be able to interpret the rotation matrix in that spec.

I chose that coordinate system (0deg is East, positive angles are CCW)
because that's what was drilled into me through every single math
course I've ever taken.  Every polar equation I worked with used that
system to specify theta.

I don't want to purposely break compat with another spec, but if
Transforms really specifies positive angles as clockwise, then I think
a *lot* of people are going to be *very* confused.  If at all possible
I'd prefer to get that changed in Transforms.

~TJ
Received on Friday, 14 August 2009 14:47:36 GMT

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