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Re: ACTION-3388: Investigating ArcThrough

From: Jasper van de Gronde <th.v.d.gronde@hccnet.nl>
Date: Tue, 25 Sep 2012 19:33:37 +0200
Message-ID: <5061EAF1.8010906@hccnet.nl>
To: www-svg@w3.org
On 2012-09-25 11:30, Cameron McCormack wrote:
> Robin Berjon:
>> this all seems good to me — it's certainly an improvement. Just one
>> question:
>>
>> On 20/09/2012 09:01 , Tab Atkins Jr. wrote:
>>> 1. When the "through" point is colinear with the start and end points.
>>>   This one is really easy because it just defines a circle with
>>> infinite radius, which usually goes by the name "line".  If the
>>> "through" point is between the other two, it devolves to a lineTo
>>> between the start and end point; if the "through" point is on either
>>> end of the other two, it's the infinite line through those two points,
>>> minus the segment connecting them.
>>
>> This appears to introduce as a side-effect the ability to draw an
>> infinite line, which we don't currently have. I just wanted to point
>> this out to make sure that it does not cause any issues.
>
> It makes it unclear how patterns and gradients would paint, if they 
> are using objectBoundingBox units.  Various DOM methods that don't 
> currently return Infinity can now do so (getComputedPathLength(), 
> getBBox() properties).
Also, what would you do with the fill? If you look at the filled disk, 
it becomes a half-plane. Apart from infinite shapes being a novelty in 
SVG, this also exposes an instability. If the point approaches the line 
through the start and end points from one side it becomes a half-plane 
on that side, if the approaches from the other it becomes a half-plane 
on the other side...
Received on Tuesday, 25 September 2012 17:34:08 GMT

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