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Re: ACTION-3388: Investigating ArcThrough

From: Dmitry Baranovskiy <dmitry.baranovskiy@gmail.com>
Date: Fri, 28 Sep 2012 12:34:51 +1000
Cc: "Tab Atkins Jr." <jackalmage@gmail.com>, Robin Berjon <robin@w3.org>, Cameron McCormack <cam@mcc.id.au>, www-svg <www-svg@w3.org>
Message-Id: <7754F7BE-B728-40C0-A873-CD875A162C8D@gmail.com>
To: Alex Danilo <alex@abbra.com>
Just as a followup on Alex email, here is a small demonstration: http://raphaeljs.com/arc3.html


On 27/09/2012, at 10:49 PM, Alex Danilo wrote:

> --Original Message--:
>> On Wed, Sep 26, 2012 at 3:28 AM, Robin Berjon <robin@w3.org> wrote:
>>> On 25/09/2012 19:38 , Tab Atkins Jr. wrote:
>>>> Ooh, fill is a very good point - it's indeterminate which side is
>>>> inside and which is outside.
>>>> 
>>>> Okay, then, I relent.  In that degenerate case, we should say that no
>>>> path is drawn, and it simply moves to the end point.
>>> 
>>> 
>>> Ah, but doesn't that open the risk of there being a flicker if the point is
>>> animated? I guess that no path is drawn, but that animation ought to be
>>> careful to skip over the alignment position.
>> 
>> If you were filling, it would flicker anyway when you crossed the
>> point.  This is just a weird degenerate case with a lot of problems.
>> I'm not comfortable with this kind of flickering, or discontinuities
>> in behavior in general, but I don't see a good way to define the
>> behavior for this.
> 
> I like the simple solution of moving to the end point since it does
> eliminate the infinite behaviour simply.
> 
> The flicker is not ideal, but this is just another edge case that we
> need to specify, nothing more. We have prior issues with gradient
> focal points, etc. that aren't specified anyway, so it isn't something
> out of the ordinary.
> 
> The convenience to authors of being able to specify a through and
> end point is _immensely_ more useful than the handful of edge
> cases where animation is concerned, and as long as we specify
> the expected behaviour, it should all be OK.
> 
> If you animate your intermediate point outsided of the start->end
> line then you see junk, so be it...
> 
> Alex
>> ~TJ
>> 
>> 
>> 
> 
> 
Received on Friday, 28 September 2012 12:46:06 GMT

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