Fix GetDeviceCoordinates. In some cases PresentationSource.FromVisual(this) may return null.

Hardcodet.NotifyIcon.Wpf/Source/NotifyIconWpf/Interop/SystemInfo.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Windows.Interop;
+
+namespace Hardcodet.Wpf.TaskbarNotification.Interop
+{
+  public static class SystemInfo
+  {
+    private static Tuple<double, double> dpiFactors;
+
+    private static Tuple<double, double> DpiFactors
+    {
+      get
+      {
+        if (dpiFactors == null)        
+          using (var source = new HwndSource(new HwndSourceParameters()))
+            dpiFactors = Tuple.Create(source.CompositionTarget.TransformToDevice.M11, source.CompositionTarget.TransformToDevice.M22);        
+        return dpiFactors;
+      }
+    }
+
+    public static double DpiXFactor
+    {
+      get
+      {
+        var factors = DpiFactors;
+        return factors != null ? factors.Item1 : 1;
+      }
+    }
+
+    public static double DpiYFactor
+    {
+      get
+      {
+        var factors = DpiFactors;
+        return factors != null ? factors.Item2 : 1;
+      }
+    }         
+  }
+}

Hardcodet.NotifyIcon.Wpf/Source/NotifyIconWpf/NotifyIconWpf.csproj

@@ -47,6 +47,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="BalloonIcon.cs" />
+    <Compile Include="Interop\SystemInfo.cs" />
     <Compile Include="Interop\TrayInfo.cs">
       <SubType>Code</SubType>
     </Compile>

Hardcodet.NotifyIcon.Wpf/Source/NotifyIconWpf/TaskbarIcon.cs

@@ -962,25 +962,7 @@ namespace Hardcodet.Wpf.TaskbarNotification
         /// <returns></returns>
         private Point GetDeviceCoordinates(Point point)
         {
-            if (double.IsNaN(scalingFactor))
+          return new Point() { X = (int)(point.X / SystemInfo.DpiXFactor), Y = (int)(point.Y / SystemInfo.DpiYFactor) };
-            {
-                //calculate scaling factor in order to support non-standard DPIs
-                var presentationSource = PresentationSource.FromVisual(this);
-                if (presentationSource == null)
-                {
-                    scalingFactor = 1;
-                }
-                else
-                {
-                    var transform = presentationSource.CompositionTarget.TransformToDevice;
-                    scalingFactor = 1/transform.M11;
-                }
-            }
-
-            //on standard DPI settings, just return the point
-            if (scalingFactor == 1.0) return point;
-
-            return new Point() {X = (int) (point.X*scalingFactor), Y = (int) (point.Y*scalingFactor)};
         }
 
         #region Dispose / Exit