Small corrections to improve the DPI awareness (display scaling).

Author: moellerm

GUI/AboutBox.Designer.cs

@@ -0,0 +1,54 @@
+/*
+ 
+  This Source Code Form is subject to the terms of the Mozilla Public
+  License, v. 2.0. If a copy of the MPL was not distributed with this
+  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ 
+  Copyright (C) 2020 Michael Möller <[email protected]>
+	
+*/
+
+using System;
+using System.Drawing;
+
+namespace OpenHardwareMonitor.GUI {
+
+  public static class DpiHelper {
+    public const double LogicalDpi = 96.0;
+
+    private static double deviceDpi;
+    public static double DeviceDpi {
+      get {
+        if (deviceDpi == 0.0) {
+          try {
+            using (Graphics g = Graphics.FromHwnd(IntPtr.Zero)) {
+              deviceDpi = g.DpiX;
+            }
+          } catch { }
+          if (deviceDpi == 0.0)
+            deviceDpi = LogicalDpi;
+        }
+        return deviceDpi;
+      }
+    }
+
+    private static double logicalToDeviceUnitsScalingFactor;
+    public static double LogicalToDeviceUnitsScalingFactor {
+      get {
+        if (logicalToDeviceUnitsScalingFactor == 0.0) {
+          logicalToDeviceUnitsScalingFactor = DeviceDpi / LogicalDpi;
+        }
+        return logicalToDeviceUnitsScalingFactor;
+      }
+    }
+
+    public static int LogicalToDeviceUnits(int value) {
+      return (int)Math.Round(LogicalToDeviceUnitsScalingFactor * (double)value);
+    }
+
+    public static Size LogicalToDeviceUnits(Size logicalSize) {
+      return new Size(LogicalToDeviceUnits(logicalSize.Width),
+        LogicalToDeviceUnits(logicalSize.Height));
+    }
+  }
+}

GUI/DpiHelper.cs

@@ -112,8 +112,14 @@ public MainForm() {
       nodeTextBoxMax.DrawText += nodeTextBoxText_DrawText;
       nodeTextBoxText.EditorShowing += nodeTextBoxText_EditorShowing;
 
+      this.sensor.Width = DpiHelper.LogicalToDeviceUnits(250);
+      this.value.Width = DpiHelper.LogicalToDeviceUnits(100);
+      this.min.Width = DpiHelper.LogicalToDeviceUnits(100);
+      this.max.Width = DpiHelper.LogicalToDeviceUnits(100);
+
       foreach (TreeColumn column in treeView.Columns) 
-        column.Width = Math.Max(20, Math.Min(400,
+        column.Width = Math.Max(DpiHelper.LogicalToDeviceUnits(20), Math.Min(
+          DpiHelper.LogicalToDeviceUnits(400),
           settings.GetValue("treeView.Columns." + column.Header + ".Width",
           column.Width)));
 
@@ -131,7 +137,8 @@ public MainForm() {
       systemTray.ExitCommand += exitClick;
 
       if (Hardware.OperatingSystem.IsUnix) { // Unix
-        treeView.RowHeight = Math.Max(treeView.RowHeight, 18); 
+        treeView.RowHeight = Math.Max(treeView.RowHeight,
+          DpiHelper.LogicalToDeviceUnits(18)); 
         splitContainer.BorderStyle = BorderStyle.None;
         splitContainer.Border3DStyle = Border3DStyle.Adjust;
         splitContainer.SplitterWidth = 4;
@@ -142,7 +149,9 @@ public MainForm() {
         minTrayMenuItem.Visible = false;
         startMinMenuItem.Visible = false;
       } else { // Windows
-        treeView.RowHeight = Math.Max(treeView.Font.Height + 1, 18); 
+        treeView.RowHeight = Math.Max(treeView.Font.Height +
+          DpiHelper.LogicalToDeviceUnits(1),
+          DpiHelper.LogicalToDeviceUnits(18)); 
 
         gadget = new SensorGadget(computer, settings, unitManager);
         gadget.HideShowCommand += hideShowClick;
@@ -617,8 +626,10 @@ private void MainForm_Load(object sender, EventArgs e) {
       Rectangle newBounds = new Rectangle {
         X = settings.GetValue("mainForm.Location.X", Location.X),
         Y = settings.GetValue("mainForm.Location.Y", Location.Y),
-        Width = settings.GetValue("mainForm.Width", 470),
-        Height = settings.GetValue("mainForm.Height", 640)
+        Width = settings.GetValue("mainForm.Width",
+          DpiHelper.LogicalToDeviceUnits(470)),
+        Height = settings.GetValue("mainForm.Height",
+          DpiHelper.LogicalToDeviceUnits(640))
       };
 
       Rectangle fullWorkingArea = new Rectangle(int.MaxValue, int.MaxValue,

GUI/MainForm.Designer.cs

@@ -69,6 +69,7 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="GUI\DpiHelper.cs" />
     <Compile Include="GUI\GadgetWindow.cs" />
     <Compile Include="GUI\Gadget.cs" />
     <Compile Include="GUI\HardwareTypeImage.cs" />