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Re: Again with the getIntersectionList()

From: Doug Schepers <schepers@w3.org>
Date: Thu, 19 Nov 2009 12:34:37 -0500
Message-ID: <4B0581AD.1040708@w3.org>
To: Boris Zbarsky <bzbarsky@MIT.EDU>
CC: www-svg <www-svg@w3.org>, Jeff Schiller <codedread@gmail.com>
Hi, Boris-

You're right, these methods certainly need more attention and 
clarification.  We'll talk about this today... thanks for your valuable 
feedback.

Regards-
-Doug Schepers
W3C Team Contact, SVG and WebApps WGs


Boris Zbarsky wrote (on 11/13/09 11:26 AM):
> On 11/13/09 3:49 AM, Doug Schepers wrote:
>> A) SVGRect1 {x:20, y:20, width:0, height:0}
>> getIntersectionList( SVGRect1 );
>>
>> This is essentially a point that will return everything that intersects
>> that point, regardless of document order
>
> I would have actually expected this to return nothing, since all
> intersections are empty (zero area)...
>
> If that's not what's intended, the spec needs to be _very_ clear on
> this, and then all sorts of interesting issues are raised. For example,
> does a rectangle with x=0,y=0,width=5,height=5 intersect a rectangle
> with x=5,y=5,width=5,height=5? I posit the intuitive answer that most
> people would want is "no". How is this different from the case above?
>
> For what it's worth, in Gecko rectangles in the css renderer are
> effectively considered closed on top and left and open on bottom and
> right; so a rectangle with x=0,y=0,width=5,height=5 is described by the
> inequalities: 0 <= x < 5, 0 <= y < 5. Hence the two rectangles I
> describe above do not in fact intersect, and any rectangle with width=0
> or height=0 is the empty set.
>
> I'm not sure what Gecko's svg implementation does in this regard, though
> I suspect it's similar.
>
> -Boris
>
Received on Thursday, 19 November 2009 17:34:47 GMT

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