Base: Add WindowsEx, ScreenEx

Base/ScreenEx.vb

@@ -1,11 +1,30 @@
 Imports System
 Imports System.Drawing
+Imports System.Runtime.InteropServices
 Imports System.Windows.Forms
+Imports DigitalData.Modules.Base.NativeMethods
 
 Public Class ScreenEx
     Public Const DEFAULT_WINDOW_HEIGHT = 480
     Public Const DEFAULT_WINDOW_WIDTH = 640
 
+    Friend Const MONITORINFOF_PRIMARY As Integer = &H1
+    Friend Const MONITOR_DEFAULTTONEAREST As Integer = &H2
+    Friend Const MONITOR_DEFAULTTONULL As Integer = &H0
+    Friend Const MONITOR_DEFAULTTOPRIMARY As Integer = &H1
+
+    Friend Enum Monitor_DPI_Type As Integer
+        MDT_Effective_DPI = 0
+        MDT_Angular_DPI = 1
+        MDT_Raw_DPI = 2
+        MDT_Default = MDT_Effective_DPI
+    End Enum
+
+    Private Enum DeviceCap
+        VERTRES = 10
+        DESKTOPVERTRES = 117
+    End Enum
+
     Public Shared Function GetLocationWithinScreen(pLocation As Point) As Point?
         For Each screen As Screen In Screen.AllScreens
             If screen.Bounds.Contains(pLocation) Then
@@ -100,4 +119,45 @@ Public Class ScreenEx
 
         Return False
     End Function
+
+    Public Function GetScreenScaling(Form As Form) As Single
+        Dim oHandle As IntPtr = Form.Handle
+        Dim oFactor1, oFactor2 As Single
+
+        oFactor1 = GetFactorFromDeviceCaps(oHandle)
+        oFactor2 = GetDPIFromMonitor(oHandle)
+
+        If oFactor1 > 1 Then
+            Return oFactor1
+        Else
+            Return oFactor2
+        End If
+    End Function
+
+    Private Function GetFactorFromDeviceCaps(Handle As IntPtr) As Single
+        Dim g As Graphics = Graphics.FromHwnd(Handle)
+        Dim desktop As IntPtr = g.GetHdc()
+        Dim LogicalScreenHeight As Integer = GetDeviceCaps(desktop, DeviceCap.VERTRES)
+        Dim PhysicalScreenHeight As Integer = GetDeviceCaps(desktop, DeviceCap.DESKTOPVERTRES)
+        Dim oScreenScalingFactor As Single = CSng(PhysicalScreenHeight) / CSng(LogicalScreenHeight)
+        Return oScreenScalingFactor
+    End Function
+
+    Private Function GetDPIFromMonitor(Handle As IntPtr) As Single
+        'Get handle to monitor that contains this window.
+        Dim monitorHandle As IntPtr = MonitorFromWindow(Handle, MONITOR_DEFAULTTONEAREST)
+
+        'Get DPI (If the OS is not Windows 8.1 or newer, calling GetDpiForMonitor will cause exception).
+        Dim dpiX As UInteger
+        Dim dpiY As UInteger
+
+        Dim result As Integer = GetDpiForMonitor(monitorHandle, Monitor_DPI_Type.MDT_Default, dpiX, dpiY)
+
+
+        If (result = 0) Then 'If S_OK (= 0)
+            Return dpiX / 96.0F
+        Else
+            Return -1
+        End If
+    End Function
 End Class