Fix for the DPI issue described in #26

src/NotifyIconWpf/Interop/SystemInfo.cs

@@ -21,6 +21,7 @@
 //
 // THIS COPYRIGHT NOTICE MAY NOT BE REMOVED FROM THIS FILE
 
+using System.Diagnostics.Contracts;
 using System.Windows.Interop;
 
 namespace Hardcodet.Wpf.TaskbarNotification.Interop
@@ -30,12 +31,18 @@ namespace Hardcodet.Wpf.TaskbarNotification.Interop
     /// </summary>
     public static class SystemInfo
     {
+        /// <summary>
+        /// Make sure the initial value is calculated at the first access
+        /// </summary>
         static SystemInfo()
         {
-            UpdateFactors();
+            UpdateDpiFactors();
         }
 
-        internal static void UpdateFactors()
+        /// <summary>
+        /// This calculates the current DPI values and sets this into the DpiFactorX/DpiFactorY values
+        /// </summary>
+        internal static void UpdateDpiFactors()
         {
             using (var source = new HwndSource(new HwndSourceParameters()))
             {
@@ -59,5 +66,20 @@ namespace Hardcodet.Wpf.TaskbarNotification.Interop
         /// Returns the DPI Y Factor
         /// </summary>
         public static double DpiFactorY { get; private set; } = 1;
+
+        /// <summary>
+        /// Scale the supplied point to the current DPI settings
+        /// </summary>
+        /// <param name="point"></param>
+        /// <returns>Point</returns>
+        [Pure]
+        public static Point ScaleWithDpi(this Point point)
+        {
+            return new Point
+            {
+                X = (int)(point.X / DpiFactorX),
+                Y = (int)(point.Y / DpiFactorY)
+            };
+        }
     }
 }

src/NotifyIconWpf/Interop/TrayInfo.cs

@@ -51,13 +51,6 @@ namespace Hardcodet.Wpf.TaskbarNotification.Interop
         /// </summary>
         /// <param name="point">Point</param>
         /// <returns>Point</returns>
-        public static Point GetDeviceCoordinates(Point point)
-        {
-          return new Point
-          {
-              X = (int)(point.X / SystemInfo.DpiFactorX),
-              Y = (int)(point.Y / SystemInfo.DpiFactorY)
-          };
-        }
+        public static Point GetDeviceCoordinates(Point point) => point.ScaleWithDpi();
     }
 }

src/NotifyIconWpf/Interop/WindowClass.cs

@@ -9,7 +9,6 @@ namespace Hardcodet.Wpf.TaskbarNotification.Interop
     /// </summary>
     public delegate IntPtr WindowProcedureHandler(IntPtr hWnd, uint uMsg, IntPtr wParam, IntPtr lParam);
 
-
     /// <summary>
     /// Win API WNDCLASS struct - represents a single window.
     /// Used to receive window messages.

src/NotifyIconWpf/Interop/WindowMessageSink.cs

@@ -6,10 +6,10 @@
 // modify it under the terms of the Code Project Open License (CPOL);
 // either version 1.0 of the License, or (at your option) any later
 // version.
-// 
+//
 // The above copyright notice and this permission notice shall be
 // included in all copies or substantial portions of the Software.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 // OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
@@ -70,7 +70,7 @@ namespace Hardcodet.Wpf.TaskbarNotification.Interop
 
         /// <summary>
         /// Handle for the message window.
-        /// </summary> 
+        /// </summary>
         internal IntPtr MessageWindowHandle { get; private set; }
 
         /// <summary>
@@ -223,9 +223,21 @@ namespace Hardcodet.Wpf.TaskbarNotification.Interop
         /// <param name="lParam">Provides information about the event.</param>
         private void ProcessWindowMessage(uint msg, IntPtr wParam, IntPtr lParam)
         {
-            if (msg != CallbackMessageId) return;
+            // Check if it was a callback message
+            if (msg != CallbackMessageId)
+            {
+                // It was not a callback message, but make sure it's not something else we need to process
+                switch ((WindowsMessages) msg)
+                {
+                    case WindowsMessages.WM_DPICHANGED:
+                        Debug.WriteLine("DPI Change");
+                        SystemInfo.UpdateDpiFactors();
+                        break;
+                }
+                return;
+            }
 
-            var message = (WindowsMessages) lParam.ToInt32();
+            var message = (WindowsMessages)lParam.ToInt32();
             Debug.WriteLine("Got message " + message);
             switch (message)
             {
@@ -338,7 +350,7 @@ namespace Hardcodet.Wpf.TaskbarNotification.Interop
 
             // This object will be cleaned up by the Dispose method.
             // Therefore, you should call GC.SuppressFinalize to
-            // take this object off the finalization queue 
+            // take this object off the finalization queue
             // and prevent finalization code for this object
             // from executing a second time.
             GC.SuppressFinalize(this);

src/NotifyIconWpf/Interop/WindowsMessages.cs

@@ -6,10 +6,10 @@
 // modify it under the terms of the Code Project Open License (CPOL);
 // either version 1.0 of the License, or (at your option) any later
 // version.
-// 
+//
 // The above copyright notice and this permission notice shall be
 // included in all copies or substantial portions of the Software.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 // OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
@@ -37,8 +37,8 @@ namespace Hardcodet.Wpf.TaskbarNotification.Interop
         /// <summary>
         /// Notifies a window that the user clicked the right mouse button (right-clicked) in the window.
         /// See <a href="https://docs.microsoft.com/en-us/windows/win32/menurc/wm-contextmenu">WM_CONTEXTMENU message</a>
-        /// 
-        /// In case of a notify icon: 
+        ///
+        /// In case of a notify icon:
         /// If a user selects a notify icon's shortcut menu with the keyboard, the Shell now sends the associated application a WM_CONTEXTMENU message. Earlier versions send WM_RBUTTONDOWN and WM_RBUTTONUP messages.
         /// See <a href="https://docs.microsoft.com/en-us/windows/win32/api/shellapi/nf-shellapi-shell_notifyiconw">Shell_NotifyIcon function</a>
         /// </summary>
@@ -57,7 +57,7 @@ namespace Hardcodet.Wpf.TaskbarNotification.Interop
         /// Posted when the user presses the left mouse button while the cursor is in the client area of a window.
         /// If the mouse is not captured, the message is posted to the window beneath the cursor.
         /// Otherwise, the message is posted to the window that has captured the mouse.
-        /// 
+        ///
         /// See <a href="https://docs.microsoft.com/en-us/windows/win32/inputdev/wm-lbuttondown">WM_LBUTTONDOWN message</a>
         /// </summary>
         WM_LBUTTONDOWN = 0x0201,
@@ -134,6 +134,13 @@ namespace Hardcodet.Wpf.TaskbarNotification.Interop
         /// </summary>
         WM_MBUTTONDBLCLK = 0x0209,
 
+        /// <summary>
+        /// Sent when the effective dots per inch (dpi) for a window has changed.
+        /// The DPI is the scale factor for a window.
+        /// There are multiple events that can cause the DPI to change.
+        /// </summary>
+        WM_DPICHANGED = 0x02e0,
+
         /// <summary>
         /// Used to define private messages for use by private window classes, usually of the form WM_USER+x, where x is an integer value.
         /// </summary>

src/NotifyIconWpf/TaskbarIcon.cs

@@ -6,10 +6,10 @@
 // modify it under the terms of the Code Project Open License (CPOL);
 // either version 1.0 of the License, or (at your option) any later
 // version.
-// 
+//
 // The above copyright notice and this permission notice shall be
 // included in all copies or substantial portions of the Software.
-// 
+//
 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 // OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
@@ -561,7 +561,7 @@ namespace Hardcodet.Wpf.TaskbarNotification
                     HasDropShadow = false,
                     BorderThickness = new Thickness(0),
                     Background = System.Windows.Media.Brushes.Transparent,
-                    // setting the 
+                    // setting the
                     StaysOpen = true,
                     Content = TrayToolTip
                 };
@@ -1049,7 +1049,7 @@ namespace Hardcodet.Wpf.TaskbarNotification
 
             // This object will be cleaned up by the Dispose method.
             // Therefore, you should call GC.SuppressFinalize to
-            // take this object off the finalization queue 
+            // take this object off the finalization queue
             // and prevent finalization code for this object
             // from executing a second time.
             GC.SuppressFinalize(this);

src/Sample Project/Sample Project.csproj

@@ -5,6 +5,7 @@
     <RootNamespace>Samples</RootNamespace>
     <AssemblyTitle>Sample Project</AssemblyTitle>
     <Product>Sample Project</Product>
+    <ApplicationManifest>app.manifest</ApplicationManifest>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\NotifyIconWpf\NotifyIconWpf.csproj" />

src/Sample Project/app.manifest

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0" xmlns:asmv2="urn:schemas-microsoft-com:asm.v2" xmlns:asmv3="urn:schemas-microsoft-com:asm.v3">
+  <!-- Make sure windows Vista and above treat Greenshot as "DPI Aware" See: http://msdn.microsoft.com/en-us/library/ms633543.aspx -->
+  <asmv3:application>
+    <asmv3:windowsSettings>
+      <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">True/PM</dpiAware>
+      <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">PerMonitorV2,PerMonitor</dpiAwareness>
+      <longPathAware xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">true</longPathAware>
+      <gdiScaling xmlns="http://schemas.microsoft.com/SMI/2017/WindowsSettings">false</gdiScaling>
+    </asmv3:windowsSettings>
+  </asmv3:application>
+  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
+    <application>
+      <!-- Windows 10 -->
+      <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}" />
+      <maxversiontested Id="10.0.18363.0"/>
+      <!-- Windows 8.1 -->
+      <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}" />
+      <!--Windows 8 -->
+      <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}" />
+      <!-- Windows 7 -->
+      <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}" />
+    </application>
+  </compatibility>
+  <!-- Set UAC level to "asInvoker" and disable registry virtualization -->
+  <asmv2:trustInfo>
+    <asmv2:security>
+      <asmv3:requestedPrivileges>
+        <!--
+          The presence of the "requestedExecutionLevel" node will disable
+          file and registry virtualization on Vista. See:
+          http://msdn.microsoft.com/en-us/library/aa965884%28v=vs.85%29.aspx
+
+          Use the "level" attribute to specify the User Account Control level:
+            asInvoker            = Never prompt for elevation
+            requireAdministrator = Always prompt for elevation
+            highestAvailable     = Prompt for elevation when started by administrator,
+                                   but do not prompt for administrator password when started by
+                                   standard user.
+        -->
+        <asmv3:requestedExecutionLevel level="asInvoker" />
+      </asmv3:requestedPrivileges>
+    </asmv2:security>
+  </asmv2:trustInfo>
+</assembly>

src/Windowless Sample/Windowless Sample.csproj

@@ -5,6 +5,7 @@
     <RootNamespace>Windowless_Sample</RootNamespace>
     <AssemblyTitle>Windowless Sample</AssemblyTitle>
     <Product>Windowless Sample</Product>
+    <ApplicationManifest>app.manifest</ApplicationManifest>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\NotifyIconWpf\NotifyIconWpf.csproj" />

src/Windowless Sample/app.manifest

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0" xmlns:asmv2="urn:schemas-microsoft-com:asm.v2" xmlns:asmv3="urn:schemas-microsoft-com:asm.v3">
+  <!-- Make sure windows Vista and above treat Greenshot as "DPI Aware" See: http://msdn.microsoft.com/en-us/library/ms633543.aspx -->
+  <asmv3:application>
+    <asmv3:windowsSettings>
+      <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">True/PM</dpiAware>
+      <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">PerMonitorV2,PerMonitor</dpiAwareness>
+      <longPathAware xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">true</longPathAware>
+      <gdiScaling xmlns="http://schemas.microsoft.com/SMI/2017/WindowsSettings">false</gdiScaling>
+    </asmv3:windowsSettings>
+  </asmv3:application>
+  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
+    <application>
+      <!-- Windows 10 -->
+      <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}" />
+      <maxversiontested Id="10.0.18363.0"/>
+      <!-- Windows 8.1 -->
+      <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}" />
+      <!--Windows 8 -->
+      <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}" />
+      <!-- Windows 7 -->
+      <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}" />
+    </application>
+  </compatibility>
+  <!-- Set UAC level to "asInvoker" and disable registry virtualization -->
+  <asmv2:trustInfo>
+    <asmv2:security>
+      <asmv3:requestedPrivileges>
+        <!--
+          The presence of the "requestedExecutionLevel" node will disable
+          file and registry virtualization on Vista. See:
+          http://msdn.microsoft.com/en-us/library/aa965884%28v=vs.85%29.aspx
+
+          Use the "level" attribute to specify the User Account Control level:
+            asInvoker            = Never prompt for elevation
+            requireAdministrator = Always prompt for elevation
+            highestAvailable     = Prompt for elevation when started by administrator,
+                                   but do not prompt for administrator password when started by
+                                   standard user.
+        -->
+        <asmv3:requestedExecutionLevel level="asInvoker" />
+      </asmv3:requestedPrivileges>
+    </asmv2:security>
+  </asmv2:trustInfo>
+</assembly>

src/WindowsFormsSample/WindowsFormsSample.csproj

@@ -6,6 +6,7 @@
     <AssemblyTitle>WindowsFormsSample</AssemblyTitle>
     <Product>WindowsFormsSample</Product>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <ApplicationManifest>app.manifest</ApplicationManifest>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\NotifyIconWpf\NotifyIconWpf.csproj" />

src/WindowsFormsSample/app.manifest

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0" xmlns:asmv2="urn:schemas-microsoft-com:asm.v2" xmlns:asmv3="urn:schemas-microsoft-com:asm.v3">
+  <!-- Make sure windows Vista and above treat Greenshot as "DPI Aware" See: http://msdn.microsoft.com/en-us/library/ms633543.aspx -->
+  <asmv3:application>
+    <asmv3:windowsSettings>
+      <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">True/PM</dpiAware>
+      <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">PerMonitorV2,PerMonitor</dpiAwareness>
+      <longPathAware xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">true</longPathAware>
+      <gdiScaling xmlns="http://schemas.microsoft.com/SMI/2017/WindowsSettings">false</gdiScaling>
+    </asmv3:windowsSettings>
+  </asmv3:application>
+  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
+    <application>
+      <!-- Windows 10 -->
+      <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}" />
+      <maxversiontested Id="10.0.18363.0"/>
+      <!-- Windows 8.1 -->
+      <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}" />
+      <!--Windows 8 -->
+      <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}" />
+      <!-- Windows 7 -->
+      <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}" />
+    </application>
+  </compatibility>
+  <!-- Set UAC level to "asInvoker" and disable registry virtualization -->
+  <asmv2:trustInfo>
+    <asmv2:security>
+      <asmv3:requestedPrivileges>
+        <!--
+          The presence of the "requestedExecutionLevel" node will disable
+          file and registry virtualization on Vista. See:
+          http://msdn.microsoft.com/en-us/library/aa965884%28v=vs.85%29.aspx
+
+          Use the "level" attribute to specify the User Account Control level:
+            asInvoker            = Never prompt for elevation
+            requireAdministrator = Always prompt for elevation
+            highestAvailable     = Prompt for elevation when started by administrator,
+                                   but do not prompt for administrator password when started by
+                                   standard user.
+        -->
+        <asmv3:requestedExecutionLevel level="asInvoker" />
+      </asmv3:requestedPrivileges>
+    </asmv2:security>
+  </asmv2:trustInfo>
+</assembly>