title: WPF: How to draw this polygon?
body: <p>I want to draw the following red polygon:
  <img src="https://i.stack.imgur.com/Z7tJE.jpg" alt="enter image description here"></p>
  
  <p>The problem is if I use somethign like this:</p>
  
  <pre><code>Polygon poly = new Polygon();
  poly.StrokeThickness = 2;
  poly.Stroke = Brushes.Black;
  PointCollection points = new PointCollection();
  
  for (int i = 0; i &lt; this.NumberOfMetrics; i++)
  {
     points.Add(new Point(MAX_VALUE - this.Metrics[n, i] * Math.Cos(DegreeToRadian(i * (360 / (this.NumberOfMetrics)))), MAX_Y_GUI - this.Metrics[n, i] * Math.Sin(DegreeToRadian(i * (360 / (this.NumberOfMetrics))))));
  }       
  poly.Points = points;
  </code></pre>
  
  <p>Then the polygon is always "filled" and in the example above the red and green polygon is drawn.</p>
  
  <p>I already tried to add the 4 "inner" points to the PointCollection, but then nothing is drawn. So how can I achieve that?</p>
  
  <p>I tried the solution proposed by David:</p>
  
  <pre><code>for (int n = 0; n &lt; this.NumberOfRevisions; n++)
              {
                  Path path = new Path();
  
                  CombinedGeometry geometry = new CombinedGeometry();
                  geometry.GeometryCombineMode = GeometryCombineMode.Union;
  
                  Polygon poly = new Polygon();
                  PointCollection points = new PointCollection();
  
                  for (int i = 0; i &lt; this.NumberOfMetrics; i++)
                  {
                      points.Add(new Point(MAX_VALUE - this.Metrics[n, i] * Math.Cos(DegreeToRadian(i * (360 / (this.NumberOfMetrics)))), MAX_Y_GUI - this.Metrics[n, i] * Math.Sin(DegreeToRadian(i * (360 / (this.NumberOfMetrics))))));
                  }
  
                  poly.Points = points;
  
                  geometry.Geometry1 = poly.RenderedGeometry;
  
  
                  geometry.Geometry2 = poly.RenderedGeometry;
  
  
                  path.Data = geometry;
  
                  polygons.Add(poly);
  
                  paths.Add(path);
              }
  </code></pre>
  
  <p>This is just a test but I thougth so I should get the same result as before, but it isn't drawn anything. Is there something wrong with my code?</p>