Hi,
Sorry in advance if I'm misunderstanding the problem. Svg paths can
often be made into closed paths by making sure to add the 1st vertex to the
end.
From an algorithm point of view there are lots of sites that have
information. Here is a discussion chosen at random from a google search:
http://www.acm.org/pubs/tog/editors/erich/ptinpoly/
The basic idea (after closing the path) is to draw a ray from the point in
question to infinity(or just very large relative to the path space) and then
count the number of times the line intersects a segment of the closed path.
If the count is odd the point is inside if even not.
Although, you might be inside a hole (Moveto) which could be
considered inside an outer ring, but outside the inner ring and thus outside
the multi ring. If a closed path is self intersecting life is equally
complicated, so that self-intersection is generally defined away by
preconditioning into multiple paths. .. and we haven't even brought up
correct intersection of cubic Bezier curve segments.
Here is the classic Java api for geometric calcs:
http://www.vividsolutions.com/jts/jtshome.htm - LPGL
Randy
<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 20001102//EN"
"http://www.w3.org/TR/SVG/DTD/svg10.dtd"; >
<svg
xmlns:xlink="http://www.w3.org/1999/xlink";
xmlns="http://www.w3.org/2000/svg";
width="600" height="600"
preserveAspectRatio="xMinYMin"
viewBox="5.317441 -30.263707 7.082269240963304 28.294216539175043"
>
<path style="fill:white;stroke:black;stroke-width:0.1"
d="M11.3315706,-9.81481061 L12.39971036,-9.76838859 L11.70309752,-7.77224211
L10.26343073,-8.93279238 L11.37801148,-8.93279238 L7.61630154,-10.46471881
L9.10240909,-11.253893 L9.79902205,-10.04692071 L10.58851676,-13.29646157
L12.02818356,-12.55370933 L10.77428016,-11.71811312
L11.65665664,-11.30031502 L11.19224796,-10.46471881 L11.3315706,-9.81481061
"/>
<line style="stroke:red;stroke-width:0.1" x1="10.449194"
y1="-10.603984" x2="5.433580" y2="-10.603984"/>
</svg>
-----Original Message-----
From: [email protected] [mailto:[EMAIL PROTECTED]
On Behalf Of rs274d
Sent: Friday, January 19, 2007 8:20 AM
To: [email protected]
Subject: [svg-developers] Re: Need help determining if a point is inside or
outside of a closed path
--- In [email protected], "vmmdragon" <[EMAIL PROTECTED]> wrote:
>
> --- In [email protected], "rs274d" <jge14@> wrote:
> >
> > Can anyone someone guide me in determining if a point is inside or
> > outside of a closed path? I can manage this for polygons but I'm lost
> > where to start on paths. Alternatively has someone written code they
> > would share on converting paths to polygons? Any help is much
> appreciated.
> >
> > Thanks,
> >
> > Jeff E.
> >
>
> Take a look at http://kevlindev.com/geometry/
> he's got a great working SVG example.
>
> M.
>
M.
Thanks for the pointer - but I could not find an example of
determining if a point is inside or outside of a path. Lots of
examples of intersection with paths and an example of a point in a
polygon.
What I'm trying to do is determine if a point (start of a piece of
text) in layer 1 is inside or outside of a several paths (mixed
absolute and relative) on layer 2.
I have this working great if layer 2 containing polygons but I am
struggling for a way to do the same with paths.
Many Thanks,
Jeff E.
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