[.Net 3.0]Point inside a polygon

  • Thread starter Thread starter Oriane
  • Start date Start date
O

Oriane

Hi there,

I'm looking for a boolean method the result of which is true if a 2D point
is *inside* a polygon - anf false otherwise. I suppose that this is existing
in the WPF class like PointCollection, but I can't find it.

Oriane
 
Hi Oriane,

You can get the geometry of the Polygon through its RenderedGeometry
property and call the FillContain(Point) method on the returned geometry
object to detect whether the geometry contains the specifed point or not.

The following is a sample:

Geometry geo = this.polygon.RenderedGeometry;
bool result = geo.FillContain(new Point(20,20));

Hope this helps.
If you have any question, please feel free to let me know.

Sincerely,
Linda Liu
Microsoft Online Community Support

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Hi Oriane,

How about the problem now? Have you had a chance to try my suggestion?

If you have any question, please feel free to let me know.

Thank you for using our MSDN Managed Newsgroup Support Service!

Sincerely,
Linda Liu
Microsoft Online Community Support

Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
(e-mail address removed).

This posting is provided "AS IS" with no warranties, and confers no rights.
 
Hi Linda,
Linda Liu said:
How about the problem now? Have you had a chance to try my suggestion?
Click to expand...

Yes but I just realize that this code:

**************************************
System.Windows.Shapes.Polygon p = new Polygon (...);
Geometry geo = p.RenderedGeometry;
**************************************
does not work (at least for me) since the geo object has empty Bounds... The
p object is not empty and filled with these points: Points {29,61;62,94
35,5;62,94 35,5;57,1 29,61;57,1}. So I don't really see what to do.

A very exciting point about WPF is that it provides us with a mathematicl
library (at least for vector calculus), and I just discover that this code
is possible:

void OneStepTowardGoal ( Point3D goal, Point3D currentPos, double dT)
{
Vector v = goal - currentPos;
v.Normalize();
Vector deltaV = v * speed * dT;
this.currentPos += deltaV;
}

which is exactly what I look for.

Best regards
 
Hi Oriane,

Thank you for your reply!
...The p object is not empty and filled with these points: Points
Click to expand...
{29,61;62,94 35,5;62,94 35,5;57,1 29,61;57,1}.

You may try the following code snippet to see if the problem can be solved:

PathGeometry pathGeo = new PathGeometry();
PathFigure pathFigure = new PathFigure();
PolyLineSegment seg = new PolyLineSegment();
PointCollection ponts = new
PointCollectionConverter().ConvertFromString("62,94 35,5 62,94 35,5 57,1
29,61 57,1") as PointCollection;
seg.Points = ponts;
pathFigure.StartPoint = new Point(29, 61);
pathFigure.Segments.Add(seg);
pathGeo.Figures.Add(pathFigure);
bool r =pathGeo.FillContains(new Point(-10, -10));
r = pathGeo.FillContains(new Point(0, 0));

Hope this helps.

Sincerely,
Linda Liu
Microsoft Online Community Support

Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
(e-mail address removed).

This posting is provided "AS IS" with no warranties, and confers no rights.
 
Linda Liu said:
Hi Oriane,

Thank you for your reply!

{29,61;62,94 35,5;62,94 35,5;57,1 29,61;57,1}.

You may try the following code snippet to see if the problem can be
solved:

PathGeometry pathGeo = new PathGeometry();
PathFigure pathFigure = new PathFigure();
PolyLineSegment seg = new PolyLineSegment();
PointCollection ponts = new
PointCollectionConverter().ConvertFromString("62,94 35,5 62,94 35,5 57,1
29,61 57,1") as PointCollection;
seg.Points = ponts;
pathFigure.StartPoint = new Point(29, 61);
pathFigure.Segments.Add(seg);
pathGeo.Figures.Add(pathFigure);
bool r =pathGeo.FillContains(new Point(-10, -10));
r = pathGeo.FillContains(new Point(0, 0));

Hope this helps.
Click to expand...
Indeed it has helped !

Thanks

Oriane
 
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