Fix FlagsEditorControl unreadable text on Visual Studio dark theme

Scintilla.NET/ColorSpace.cs

@@ -0,0 +1,97 @@
+using System;
+using System.Drawing;
+
+namespace ScintillaNET;
+
+internal class ColorSpace
+{
+    public static float SrgbToLinearSrgb(float x) =>
+        x >= 0.04045 ? (float)Math.Pow((x + 0.055f) / (1 + 0.055f), 2.4f) : x / 12.92f;
+
+    public static float LinearSrgbToSrgb(float x) =>
+        x >= 0.0031308 ? 1.055f * (float)Math.Pow(x, 1.0 / 2.4) - 0.055f : 12.92f * x;
+}
+
+/// <summary>
+/// OkLab color.
+/// </summary>
+/// <param name="L">Luminance (perceived lightness) in range [0.0, 1.0].</param>
+/// <param name="a">How green/red the color is in range [-0.233887, +0.276216].</param>
+/// <param name="b">How blue/yellow the color is in range [-0.311528, +0.198570].</param>
+internal struct OkLab(float L, float a, float b)
+{
+    public float L = L;
+    public float a = a;
+    public float b = b;
+
+    public readonly Srgb ToLinearSrgb()
+    {
+        float l_ = this.L + 0.3963377774f * this.a + 0.2158037573f * this.b;
+        float m_ = this.L - 0.1055613458f * this.a - 0.0638541728f * this.b;
+        float s_ = this.L - 0.0894841775f * this.a - 1.2914855480f * this.b;
+
+        float l = l_ * l_ * l_;
+        float m = m_ * m_ * m_;
+        float s = s_ * s_ * s_;
+
+        return new Srgb(
+            Helpers.Clamp(+4.0767416621f * l - 3.3077115913f * m + 0.2309699292f * s, 0, 1),
+            Helpers.Clamp(-1.2684380046f * l + 2.6097574011f * m - 0.3413193965f * s, 0, 1),
+            Helpers.Clamp(-0.0041960863f * l - 0.7034186147f * m + 1.7076147010f * s, 0, 1)
+        );
+    }
+
+    public override readonly string ToString()
+    {
+        return FormattableString.Invariant($"(L:{L}, a:{a}, b:{b})");
+    }
+}
+
+/// <summary>
+/// sRGB color.
+/// </summary>
+/// <param name="R">Red component.</param>
+/// <param name="G">Green component.</param>
+/// <param name="B">Blue component.</param>
+internal struct Srgb(float R, float G, float B)
+{
+    public float R = R;
+    public float G = G;
+    public float B = B;
+
+    public readonly OkLab ToOkLab()
+    {
+        float l = 0.4122214708f * this.R + 0.5363325363f * this.G + 0.0514459929f * this.B;
+        float m = 0.2119034982f * this.R + 0.6806995451f * this.G + 0.1073969566f * this.B;
+        float s = 0.0883024619f * this.R + 0.2817188376f * this.G + 0.6299787005f * this.B;
+
+        float l_ = (float)Math.Pow(l, 1.0 / 3.0);
+        float m_ = (float)Math.Pow(m, 1.0 / 3.0);
+        float s_ = (float)Math.Pow(s, 1.0 / 3.0);
+
+        return new OkLab(
+            0.2104542553f * l_ + 0.7936177850f * m_ - 0.0040720468f * s_,
+            1.9779984951f * l_ - 2.4285922050f * m_ + 0.4505937099f * s_,
+            0.0259040371f * l_ + 0.7827717662f * m_ - 0.8086757660f * s_
+        );
+    }
+
+    public static Srgb FromColor(Color c) => new(c.R / 255.0f, c.G / 255.0f, c.B / 255.0f);
+
+    public readonly Color ToColor() => Color.FromArgb((byte)(this.R * 255), (byte)(this.G * 255), (byte)(this.B * 255));
+
+    public readonly Srgb ToLinearSrgb() =>
+        new(Helpers.Clamp(ColorSpace.SrgbToLinearSrgb(R), 0f, 1f),
+            Helpers.Clamp(ColorSpace.SrgbToLinearSrgb(G), 0f, 1f),
+            Helpers.Clamp(ColorSpace.SrgbToLinearSrgb(B), 0f, 1f));
+
+    public readonly Srgb ToSrgb() =>
+        new(Helpers.Clamp(ColorSpace.LinearSrgbToSrgb(R), 0f, 1f),
+            Helpers.Clamp(ColorSpace.LinearSrgbToSrgb(G), 0f, 1f),
+            Helpers.Clamp(ColorSpace.LinearSrgbToSrgb(B), 0f, 1f));
+
+    public override readonly string ToString()
+    {
+        return FormattableString.Invariant($"(R:{R}, G:{G}, B:{B})");
+    }
+}

Scintilla.NET/FlagsEditorControl.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using System.Windows.Forms;
 using System.Windows.Forms.Design;
@@ -51,7 +52,6 @@ public FlagsEditorControl(IWindowsFormsEditorService editorService, Enum value)
                         Tag = item,
                         Margin = new Padding(3, 0, 3, 0),
                         Padding = Padding.Empty,
-                        UseVisualStyleBackColor = true,
                     };
                     checkBox.CheckStateChanged += checkBox_CheckStateChanged;
                     this.flowLayoutPanel_CheckBoxList.Controls.Add(checkBox);
@@ -67,7 +67,6 @@ public FlagsEditorControl(IWindowsFormsEditorService editorService, Enum value)
                     Tag = (Enum)Enum.ToObject(this.enumType, allBits),
                     Margin = new Padding(3, 0, 3, 0),
                     Padding = Padding.Empty,
-                    UseVisualStyleBackColor = true,
                 };
                 checkBox.CheckStateChanged += checkBox_CheckStateChanged;
                 this.flowLayoutPanel_CheckBoxList.Controls.Add(checkBox);
@@ -81,6 +80,18 @@ public FlagsEditorControl(IWindowsFormsEditorService editorService, Enum value)
         }
     }
 
+    protected override void OnBackColorChanged(EventArgs e)
+    {
+        base.OnBackColorChanged(e);
+        Helpers.ApplyToControlTree(this, c => {
+            OkLab backColor = Srgb.FromColor(c.BackColor).ToLinearSrgb().ToOkLab();
+            if (backColor.L < 0.5f)
+                c.ForeColor = Color.White;
+            else
+                c.ForeColor = Color.Black;
+        });
+    }
+
     private static ulong CalculateEnumAllValue(Type enumType)
     {
         ulong all = 0;

Scintilla.NET/Helpers.cs

@@ -106,6 +106,11 @@ public static unsafe byte[] CharToByteStyles(byte[] styles, byte* text, int leng
         return result;
     }
 
+    public static float Clamp(float f, float min, float max)
+    {
+        return f < min ? min : f > max ? max : f;
+    }
+
     public static int Clamp(int value, int min, int max)
     {
         if (value < min)
@@ -1260,6 +1265,15 @@ public static int MaxIndex<TSource>(this IEnumerable<TSource> source, Func<TSour
         return maxIndex;
     }
 
+    public static void ApplyToControlTree(Control control, Action<Control> action)
+    {
+        foreach (Control child in control.Controls)
+        {
+            ApplyToControlTree(child, action);
+        }
+        action(control);
+    }
+
     #endregion Methods
 
     #region Types