Fix issues with SystemColors and UseAlternativeColorSet.

KlausLoeffelmann · Aug 1, 2024 · 1b3e692 · 1b3e692
1 parent 17c3816
commit 1b3e692
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Showing 6 changed files with 64 additions and 8 deletions.
diff --git a/src/System.Drawing.Common/src/System/Drawing/SystemBrushes.cs b/src/System.Drawing.Common/src/System/Drawing/SystemBrushes.cs
@@ -5,6 +5,11 @@ namespace System.Drawing;
 
 public static class SystemBrushes
 {
+#if NET9_0_OR_GREATER
+#pragma warning disable SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+    private static bool s_colorSetOnLastAccess = SystemColors.UseAlternativeColorSet;
+#pragma warning restore SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+#endif
     private static readonly object s_systemBrushesKey = new();
 
     public static Brush ActiveBorder => FromSystemColor(SystemColors.ActiveBorder);
@@ -57,7 +62,20 @@ public static Brush FromSystemColor(Color c)
             throw new ArgumentException(SR.Format(SR.ColorNotSystemColor, c.ToString()));
         }
 
-        if (!Gdip.ThreadData.TryGetValue(s_systemBrushesKey, out object? tempSystemBrushes) || tempSystemBrushes is not Brush[] systemBrushes)
+#if NET9_0_OR_GREATER
+#pragma warning disable SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+        if (s_colorSetOnLastAccess != SystemColors.UseAlternativeColorSet)
+        {
+            s_colorSetOnLastAccess = SystemColors.UseAlternativeColorSet;
+
+            // We need to clear the SystemBrushes cache, when the ColorMode had changed.
+            Gdip.ThreadData.Remove(s_systemBrushesKey);
+        }
+#pragma warning restore SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+#endif
+
+        if (!Gdip.ThreadData.TryGetValue(s_systemBrushesKey, out object? tempSystemBrushes)
+            || tempSystemBrushes is not Brush[] systemBrushes)
         {
             systemBrushes = new Brush[(int)KnownColor.WindowText + (int)KnownColor.MenuHighlight - (int)KnownColor.YellowGreen];
             Gdip.ThreadData[s_systemBrushesKey] = systemBrushes;

diff --git a/src/System.Drawing.Common/src/System/Drawing/SystemPens.cs b/src/System.Drawing.Common/src/System/Drawing/SystemPens.cs
@@ -5,6 +5,12 @@ namespace System.Drawing;
 
 public static class SystemPens
 {
+#if NET9_0_OR_GREATER
+#pragma warning disable SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+    private static bool s_colorSetOnLastAccess = SystemColors.UseAlternativeColorSet;
+#pragma warning restore SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+#endif
+
     private static readonly object s_systemPensKey = new();
 
     public static Pen ActiveBorder => FromSystemColor(SystemColors.ActiveBorder);
@@ -58,7 +64,20 @@ public static Pen FromSystemColor(Color c)
             throw new ArgumentException(SR.Format(SR.ColorNotSystemColor, c.ToString()));
         }
 
-        if (!Gdip.ThreadData.TryGetValue(s_systemPensKey, out object? tempSystemPens) || tempSystemPens is not Pen[] systemPens)
+#if NET9_0_OR_GREATER
+#pragma warning disable SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+        if (s_colorSetOnLastAccess != SystemColors.UseAlternativeColorSet)
+        {
+            s_colorSetOnLastAccess = SystemColors.UseAlternativeColorSet;
+
+            // We need to clear the SystemBrushes cache, when the ColorMode had changed.
+            Gdip.ThreadData.Remove(s_systemPensKey);
+        }
+#pragma warning restore SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+#endif
+
+        if (!Gdip.ThreadData.TryGetValue(s_systemPensKey, out object? tempSystemPens)
+            || tempSystemPens is not Pen[] systemPens)
         {
             systemPens = new Pen[(int)KnownColor.WindowText + (int)KnownColor.MenuHighlight - (int)KnownColor.YellowGreen];
             Gdip.ThreadData[s_systemPensKey] = systemPens;

diff --git a/src/System.Windows.Forms.Primitives/src/System/Windows/Forms/DeviceContextExtensions.cs b/src/System.Windows.Forms.Primitives/src/System/Windows/Forms/DeviceContextExtensions.cs
@@ -95,7 +95,8 @@ internal static unsafe void DrawLines(this HDC hdc, HPEN hpen, ReadOnlySpan<int>
         }
     }
 
-    internal static Color FindNearestColor(this DeviceContextHdcScope hdc, Color color) => FindNearestColor(hdc.HDC, color);
+    internal static Color FindNearestColor(this DeviceContextHdcScope hdc, Color color) =>
+        FindNearestColor(hdc.HDC, color);
 
     /// <summary>
     ///  Calls <see cref="PInvoke.GetNearestColor(HDC, COLORREF)"/> to get the nearest color for the given
@@ -116,7 +117,22 @@ internal static unsafe void DrawLines(this HDC hdc, HPEN hpen, ReadOnlySpan<int>
     /// </remarks>
     internal static Color FindNearestColor(this HDC hdc, Color color)
     {
-        Color newColor = ColorTranslator.FromWin32((int)PInvoke.GetNearestColor(hdc, (COLORREF)(uint)ColorTranslator.ToWin32(color)).Value);
+#pragma warning disable SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+        if (color.IsSystemColor && SystemColors.UseAlternativeColorSet)
+        {
+            // We need to "un-system" the color for nearest color to work correctly in dark mode,
+            // since GetNearestColor doesn't understand dark mode system colors and internally works
+            // with the light mode colors.
+            color = Color.FromArgb(color.ToArgb());
+            Debug.Assert(!color.IsSystemColor, "Color should not be a system color.");
+        }
+#pragma warning restore SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+
+        Color newColor = ColorTranslator.FromWin32(
+            (int)PInvoke.GetNearestColor(
+                hdc: hdc,
+                color: (COLORREF)(uint)ColorTranslator.ToWin32(color)).Value);
+
         return newColor.ToArgb() == color.ToArgb() ? color : newColor;
     }
 

diff --git a/src/System.Windows.Forms.Primitives/src/Windows/Win32/CreateBrushScope.cs b/src/System.Windows.Forms.Primitives/src/Windows/Win32/CreateBrushScope.cs
@@ -28,9 +28,12 @@ internal readonly ref struct CreateBrushScope
     /// </summary>
     public CreateBrushScope(Color color)
     {
-        HBRUSH = color.IsSystemColor
+#pragma warning disable SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+        HBRUSH = color.IsSystemColor && !SystemColors.UseAlternativeColorSet
             ? PInvoke.GetSysColorBrush(color)
             : PInvoke.CreateSolidBrush(color);
+#pragma warning restore SYSLIB5002 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+
         ValidateBrushHandle();
     }
 

diff --git a/src/System.Windows.Forms/src/System/Windows/Forms/Control.cs b/src/System.Windows.Forms/src/System/Windows/Forms/Control.cs
@@ -718,7 +718,8 @@ internal HBRUSH BackColorBrush
             Color color = BackColor;
             HBRUSH backBrush;
 
-            if (color.IsSystemColor)
+#pragma warning disable WFO9001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+            if (color.IsSystemColor && !Application.IsDarkModeEnabled)
             {
                 backBrush = PInvoke.GetSysColorBrush(color);
                 SetState(States.OwnCtlBrush, false);
@@ -728,6 +729,7 @@ internal HBRUSH BackColorBrush
                 backBrush = PInvoke.CreateSolidBrush((COLORREF)(uint)ColorTranslator.ToWin32(color));
                 SetState(States.OwnCtlBrush, true);
             }
+#pragma warning restore WFO9001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
 
             Debug.Assert(!backBrush.IsNull, "Failed to create brushHandle");
             Properties.SetObject(s_backBrushProperty, backBrush);

diff --git a/src/System.Windows.Forms/src/System/Windows/Forms/Controls/ListBoxes/CheckedListBox.cs b/src/System.Windows.Forms/src/System/Windows/Forms/Controls/ListBoxes/CheckedListBox.cs
@@ -578,7 +578,6 @@ protected override void OnDrawItem(DrawItemEventArgs e)
                 textBounds.X = bounds.X;
             }
 
-#pragma warning disable WFO9001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
             Color backColor = (SelectionMode != SelectionMode.None) ? e.BackColor : BackColor;
             Color foreColor = (SelectionMode != SelectionMode.None) ? e.ForeColor : ForeColor;
             if (!Enabled)
@@ -605,7 +604,6 @@ protected override void OnDrawItem(DrawItemEventArgs e)
                     foreColor = SystemColors.GrayText;
                 }
             }
-#pragma warning restore WFO9001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
 
             // Draw the text