Fix light rendering of grids and Settings dialog in dark mode

src/LogExpert.Tests/UI/PaintHelperTests.cs

@@ -0,0 +1,198 @@
+using System.Runtime.Versioning;
+
+using LogExpert.Core.Classes.Highlight;
+using LogExpert.UI.Entities;
+
+using NUnit.Framework;
+
+namespace LogExpert.Tests.UI;
+
+[TestFixture]
+[Apartment(ApartmentState.STA)] // Required for WinForms components
+[SupportedOSPlatform("windows")]
+public class PaintHelperTests
+{
+    [Test]
+    public void ApplyGridViewTheme_DarkMode_DisablesHeaderVisualStyles ()
+    {
+        // With EnableHeadersVisualStyles = true the column headers are painted by the
+        // Windows visual-style renderer, which only exists in a light flavor and
+        // ignores Application.SetColorMode(Dark).
+        using DataGridView gridView = new();
+
+        PaintHelper.ApplyGridViewTheme(gridView, darkMode: true);
+
+        Assert.That(gridView.EnableHeadersVisualStyles, Is.False);
+    }
+
+    [Test]
+    public void ApplyGridViewTheme_LightMode_KeepsHeaderVisualStyles ()
+    {
+        using DataGridView gridView = new();
+
+        PaintHelper.ApplyGridViewTheme(gridView, darkMode: false);
+
+        Assert.That(gridView.EnableHeadersVisualStyles, Is.True);
+    }
+
+    [Test]
+    public void GetBackColorFromHighlightEntry_NoEntryInDarkMode_FallsBackToDarkColor ()
+    {
+        // A line matching no highlight rule must not get the light-mode white background.
+        var backColor = PaintHelper.GetBackColorFromHighlightEntry(null, darkMode: true);
+
+        Assert.That(IsDark(backColor), Is.True, $"expected a dark fallback color but got {backColor}");
+    }
+
+    [Test]
+    public void GetBackColorFromHighlightEntry_NoEntryInLightMode_FallsBackToWhite ()
+    {
+        var backColor = PaintHelper.GetBackColorFromHighlightEntry(null, darkMode: false);
+
+        Assert.That(backColor, Is.EqualTo(Color.White));
+    }
+
+    [Test]
+    public void GetBackColorFromHighlightEntry_EntryColor_WinsOverTheme ()
+    {
+        var entry = new HighlightEntry { BackgroundColor = Color.Red };
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(PaintHelper.GetBackColorFromHighlightEntry(entry, darkMode: true), Is.EqualTo(Color.Red));
+            Assert.That(PaintHelper.GetBackColorFromHighlightEntry(entry, darkMode: false), Is.EqualTo(Color.Red));
+        });
+    }
+
+    [Test]
+    public void GetForeColorFromHighlightEntry_NoEntryInDarkMode_FallsBackToLightColor ()
+    {
+        var foreColor = PaintHelper.GetForeColorFromHighlightEntry(null, darkMode: true);
+
+        Assert.That(IsLight(foreColor), Is.True, $"expected a light fallback color but got {foreColor}");
+    }
+
+    [Test]
+    public void GetForeColorFromHighlightEntry_NoEntryInLightMode_FallsBackToBlack ()
+    {
+        var foreColor = PaintHelper.GetForeColorFromHighlightEntry(null, darkMode: false);
+
+        Assert.That(foreColor, Is.EqualTo(Color.Black));
+    }
+
+    [Test]
+    public void GetForeColorFromHighlightEntry_EntryColor_WinsOverTheme ()
+    {
+        var entry = new HighlightEntry { ForegroundColor = Color.Red };
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(PaintHelper.GetForeColorFromHighlightEntry(entry, darkMode: true), Is.EqualTo(Color.Red));
+            Assert.That(PaintHelper.GetForeColorFromHighlightEntry(entry, darkMode: false), Is.EqualTo(Color.Red));
+        });
+    }
+
+    [Test]
+    public void GetForeColorFromHighlightEntry_EntryWithoutForeColor_FallsBackToTheme ()
+    {
+        // HighlightEntry.ForegroundColor defaults to Color.Empty ("not set").
+        var entry = new HighlightEntry();
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(IsLight(PaintHelper.GetForeColorFromHighlightEntry(entry, darkMode: true)), Is.True);
+            Assert.That(PaintHelper.GetForeColorFromHighlightEntry(entry, darkMode: false), Is.EqualTo(Color.Black));
+        });
+    }
+
+    [Test]
+    public void GetDataGridViewCellStyle_DarkMode_UsesLightForeColor ()
+    {
+        var style = PaintHelper.GetDataGridViewCellStyle(darkMode: true);
+
+        Assert.That(IsLight(style.ForeColor), Is.True, $"expected a light fore color but got {style.ForeColor}");
+    }
+
+    [Test]
+    public void GetDataGridViewCellStyle_LightMode_UsesDarkForeColor ()
+    {
+        var style = PaintHelper.GetDataGridViewCellStyle(darkMode: false);
+
+        Assert.That(IsDark(style.ForeColor), Is.True, $"expected a dark fore color but got {style.ForeColor}");
+    }
+
+    [Test]
+    public void GetDataGridDefaultRowStyle_DarkMode_UsesLightForeColor ()
+    {
+        var style = PaintHelper.GetDataGridDefaultRowStyle(darkMode: true);
+
+        Assert.That(IsLight(style.ForeColor), Is.True, $"expected a light fore color but got {style.ForeColor}");
+    }
+
+    [Test]
+    public void GetDataGridDefaultRowStyle_LightMode_UsesDarkForeColor ()
+    {
+        var style = PaintHelper.GetDataGridDefaultRowStyle(darkMode: false);
+
+        Assert.That(IsDark(style.ForeColor), Is.True, $"expected a dark fore color but got {style.ForeColor}");
+    }
+
+    [Test]
+    public void GetBrushForFocusedControl_UnfocusedDarkMode_UsesDarkGray ()
+    {
+        using var brush = (SolidBrush)PaintHelper.GetBrushForFocusedControl(focused: false, SystemColors.Highlight, darkMode: true);
+
+        Assert.That(IsDark(brush.Color), Is.True, $"expected a dark unfocused-selection color but got {brush.Color}");
+    }
+
+    [Test]
+    public void GetBrushForFocusedControl_UnfocusedLightMode_KeepsLightGray ()
+    {
+        using var brush = (SolidBrush)PaintHelper.GetBrushForFocusedControl(focused: false, SystemColors.Highlight, darkMode: false);
+
+        Assert.That(brush.Color.ToArgb(), Is.EqualTo(Color.FromArgb(255, 170, 170, 170).ToArgb()));
+    }
+
+    [Test]
+    public void GetBrushForFocusedControl_Focused_UsesSelectionColor ()
+    {
+        using var brushDark = (SolidBrush)PaintHelper.GetBrushForFocusedControl(focused: true, Color.Teal, darkMode: true);
+        using var brushLight = (SolidBrush)PaintHelper.GetBrushForFocusedControl(focused: true, Color.Teal, darkMode: false);
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(brushDark.Color, Is.EqualTo(Color.Teal));
+            Assert.That(brushLight.Color, Is.EqualTo(Color.Teal));
+        });
+    }
+
+    [Test]
+    public void ApplyTabControlTheme_DarkMode_DisablesVisualStyleBackColorOnAllPages ()
+    {
+        // With UseVisualStyleBackColor = true the tab page body is painted by the
+        // light-only visual-style renderer while child controls inherit the dark
+        // ambient color, giving light pages with dark patches in dark mode.
+        using TabControl tabControl = new();
+        tabControl.TabPages.Add(new TabPage { UseVisualStyleBackColor = true });
+        tabControl.TabPages.Add(new TabPage { UseVisualStyleBackColor = true });
+
+        PaintHelper.ApplyTabControlTheme(tabControl, darkMode: true);
+
+        Assert.That(tabControl.TabPages.Cast<TabPage>().Select(p => p.UseVisualStyleBackColor), Is.All.False);
+    }
+
+    [Test]
+    public void ApplyTabControlTheme_LightMode_KeepsVisualStyleBackColor ()
+    {
+        using TabControl tabControl = new();
+        tabControl.TabPages.Add(new TabPage { UseVisualStyleBackColor = true });
+
+        PaintHelper.ApplyTabControlTheme(tabControl, darkMode: false);
+
+        Assert.That(tabControl.TabPages[0].UseVisualStyleBackColor, Is.True);
+    }
+
+    private static bool IsDark (Color color) => color.R < 128 && color.G < 128 && color.B < 128;
+
+    private static bool IsLight (Color color) => color.R >= 128 && color.G >= 128 && color.B >= 128;
+}

src/LogExpert.UI/Controls/LogWindow/LogWindow.cs

@@ -2410,10 +2410,13 @@ private void MeasureItem (object sender, MeasureItemEventArgs e)
     [SupportedOSPlatform("windows")]
     private void CreateDefaultViewStyle ()
     {
-        dataGridView.DefaultCellStyle = PaintHelper.GetDataGridViewCellStyle();
-        filterGridView.DefaultCellStyle = PaintHelper.GetDataGridViewCellStyle();
-        dataGridView.RowsDefaultCellStyle = PaintHelper.GetDataGridDefaultRowStyle();
-        filterGridView.RowsDefaultCellStyle = PaintHelper.GetDataGridDefaultRowStyle();
+        var darkMode = Application.IsDarkModeEnabled;
+        dataGridView.DefaultCellStyle = PaintHelper.GetDataGridViewCellStyle(darkMode);
+        filterGridView.DefaultCellStyle = PaintHelper.GetDataGridViewCellStyle(darkMode);
+        dataGridView.RowsDefaultCellStyle = PaintHelper.GetDataGridDefaultRowStyle(darkMode);
+        filterGridView.RowsDefaultCellStyle = PaintHelper.GetDataGridDefaultRowStyle(darkMode);
+        PaintHelper.ApplyGridViewTheme(dataGridView, darkMode);
+        PaintHelper.ApplyGridViewTheme(filterGridView, darkMode);
     }
 
     [SupportedOSPlatform("windows")]
@@ -3591,7 +3594,7 @@ private void PaintHighlightedCell (DataGridViewCellPaintingEventArgs e, Highligh
         var he = new HighlightEntry
         {
             SearchText = column.DisplayValue.ToString(),
-            ForegroundColor = groundEntry?.ForegroundColor ?? Color.FromKnownColor(KnownColor.Black),
+            ForegroundColor = PaintHelper.GetForeColorFromHighlightEntry(groundEntry, Application.IsDarkModeEnabled),
             BackgroundColor = groundEntry?.BackgroundColor ?? Color.Empty,
             IsWordMatch = true
         };
@@ -6902,12 +6905,12 @@ public void CellPainting (bool focused, int rowIndex, int columnIndex, bool isFi
 
             if (e.State.HasFlag(DataGridViewElementStates.Selected))
             {
-                using var brush = PaintHelper.GetBrushForFocusedControl(focused, e.CellStyle.SelectionBackColor);
+                using var brush = PaintHelper.GetBrushForFocusedControl(focused, e.CellStyle.SelectionBackColor, Application.IsDarkModeEnabled);
                 e.Graphics.FillRectangle(brush, e.CellBounds);
             }
             else
             {
-                e.CellStyle.BackColor = PaintHelper.GetBackColorFromHighlightEntry(entry);
+                e.CellStyle.BackColor = PaintHelper.GetBackColorFromHighlightEntry(entry, Application.IsDarkModeEnabled);
                 e.PaintBackground(e.ClipBounds, false);
             }
 

src/LogExpert.UI/Dialogs/LogTabWindow/LogTabWindow.cs

@@ -304,6 +304,16 @@ public LogWindow.LogWindow AddTempFileTab (string fileName, string title)
 
     private void ConfigureDockPanel ()
     {
+        if (Application.IsDarkModeEnabled)
+        {
+            var darkTheme = new VS2015DarkTheme();
+            dockPanel.Theme = darkTheme;
+            dockPanel.DockBackColor = darkTheme.ColorPalette.MainWindowActive.Background;
+            dockPanel.ActiveAutoHideContent = null;
+            dockPanel.DocumentStyle = DocumentStyle.DockingWindow;
+            return;
+        }
+
         var autoHideStripSkin1 = new AutoHideStripSkin();
         var dockPanelGradient1 = new DockPanelGradient();
         var tabGradient1 = new TabGradient();

src/LogExpert.UI/Dialogs/SettingsDialog.cs

@@ -14,6 +14,7 @@
 using LogExpert.UI.Controls.LogTabWindow;
 using LogExpert.UI.Dialogs;
 using LogExpert.UI.Dialogs.Helpers;
+using LogExpert.UI.Entities;
 using LogExpert.UI.Extensions;
 
 namespace LogExpert.Dialogs;
@@ -75,6 +76,12 @@ private SettingsDialog (Preferences prefs, LogTabWindow logTabWin)
 
         InitializeComponent();
 
+        var darkMode = Application.IsDarkModeEnabled;
+        PaintHelper.ApplyTabControlTheme(tabControlSettings, darkMode);
+        PaintHelper.ApplyGridViewTheme(dataGridViewColumnizer, darkMode);
+        PaintHelper.ApplyGridViewTheme(dataGridViewHighlightMask, darkMode);
+        PaintHelper.ApplyGridViewTheme(dataGridViewControlChars, darkMode);
+
         dataGridViewImageColumnColumnizerStale.CellTemplate = new EmptyImageCell();
 
         LoadResources();