--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MetroWpf/MetroWpf.Xaml/Converters/AngleToCoordinateConverter.cs	Mon Mar 12 23:05:21 2012 +0800
@@ -0,0 +1,60 @@
+using System;
+using System.Diagnostics.Contracts;
+using System.Globalization;
+using System.Windows;
+using System.Windows.Data;
+
+namespace MetroWpf.Xaml.Converters
+{
+  public sealed class AngleToCoordinateConverter : IMultiValueConverter
+  {
+    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
+    {
+      if (values == null || values.Length < 4)
+      {
+        return DependencyProperty.UnsetValue;
+      }
+
+      var fallbackValue = values[0];
+      if (!(values[1] is double) || !(values[2] is double) || !(values[3] is double))
+      {
+        return fallbackValue;
+      }
+      var angle = (double)values[1];
+      if (angle < 0.0)
+      {
+        return fallbackValue;
+      }
+      var areaWidth = (double)values[2];
+      var areaHeight = (double)values[3];
+
+      var width = values.Length > 4 ? (values[4] is double ? (double)values[4] : 0.0) : 0.0;
+      var height = values.Length > 5 ? (values[5] is double ? (double)values[5] : 0.0) : 0.0;
+      var radiusXCoordinate = values.Length > 6 ? (values[5] is double ? (double)values[5] : 0.0) : areaWidth / 2;
+      var radiusYCoordinate = values.Length > 7 ? (values[6] is double ? (double)values[6] : 0.0) : areaHeight / 2;
+
+      var length = Math.Max(width, height);
+      var radius = Math.Min(areaWidth / 2, areaHeight / 2) - length;
+
+      switch (parameter as string)
+      {
+        case "X":
+        case "x":
+          var x = radiusXCoordinate + radius * Math.Cos(angle * Math.PI / 180);
+          return x;
+        case "Y":
+        case "y":
+          var y = radiusYCoordinate + radius * Math.Sin(angle * Math.PI / 180);
+          return y;
+        default:
+          return fallbackValue;
+      }
+    }
+
+    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
+    {
+      Contract.Ensures(false);
+      throw new NotSupportedException();
+    }
+  }
+} ;
\ No newline at end of file