title: WPF: How to draw a circle?
body: <p>I have the following code:</p>
  
  <pre><code>using Microsoft.Expression.Shapes;
  
  Arc a = new Arc();
  a.ArcThicknessUnit = Microsoft.Expression.Media.UnitType.Pixel;
  a.ArcThickness = 10;
  a.StrokeThickness = 1;
  a.Fill = new SolidColorBrush(Colors.Aqua);
  a.Stroke = new SolidColorBrush(Colors.DarkMagenta);
  a.StartAngle = 0;
  a.EndAngle = 360;
  a.Width = 200;
  a.Height = 200;
  a.Stretch = Stretch.None;
  _myStackPanel.Children.Add(a);
  
  DispatcherTimer dt = new DispatcherTimer();
  dt.Interval = TimeSpan.FromMilliseconds(1);
  dt.Tick += (s, e) =&gt; { a.StartAngle = a.StartAngle + 4; };
  dt.Start();
  </code></pre>
  
  <p>When it is executed I get an "erasable circle". I need to get the opposite effect. Сircle drawing effect. How can I change the code to get a "drawn circle"? <a href="https://i.stack.imgur.com/TuSvu.gif" rel="nofollow noreferrer">Circle Drawning Example</a></p>