Move foreground colour helper into OsuColour

osu.Game/Graphics/OsuColour.cs

@@ -94,6 +94,18 @@ namespace osu.Game.Graphics
             }
         }
 
+        /// <summary>
+        /// Returns a foreground text colour that is supposed to contrast well with
+        /// the supplied <paramref name="backgroundColour"/>.
+        /// </summary>
+        public static Color4 ForegroundTextColourFor(Color4 backgroundColour)
+        {
+            // formula taken from the RGB->YIQ conversions: https://en.wikipedia.org/wiki/YIQ
+            // brightness here is equivalent to the Y component in the above colour model, which is a rough estimate of lightness.
+            float brightness = 0.299f * backgroundColour.R + 0.587f * backgroundColour.G + 0.114f * backgroundColour.B;
+            return Gray(brightness > 0.5f ? 0.2f : 0.9f);
+        }
+
         // See https://github.com/ppy/osu-web/blob/master/resources/assets/less/colors.less
         public readonly Color4 PurpleLighter = Color4Extensions.FromHex(@"eeeeff");
         public readonly Color4 PurpleLight = Color4Extensions.FromHex(@"aa88ff");

osu.Game/Graphics/UserInterfaceV2/ColourDisplay.cs

@@ -10,7 +10,6 @@ using osu.Framework.Graphics.Shapes;
 using osu.Framework.Graphics.UserInterface;
 using osu.Framework.Localisation;
 using osu.Game.Graphics.Sprites;
-using osu.Game.Utils;
 using osuTK;
 using osuTK.Graphics;
 
@@ -102,7 +101,7 @@ namespace osu.Game.Graphics.UserInterfaceV2
         {
             fill.Colour = current.Value;
             colourHexCode.Text = current.Value.ToHex();
-            colourHexCode.Colour = ColourUtils.ForegroundTextColourFor(current.Value);
+            colourHexCode.Colour = OsuColour.ForegroundTextColourFor(current.Value);
         }
     }
 }

osu.Game/Screens/Edit/Compose/Components/Timeline/TimelineHitObjectBlueprint.cs

@@ -21,7 +21,6 @@ using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Types;
 using osu.Game.Skinning;
-using osu.Game.Utils;
 using osuTK;
 using osuTK.Graphics;
 
@@ -159,7 +158,7 @@ namespace osu.Game.Screens.Edit.Compose.Components.Timeline
                 circle.Colour = comboColour;
 
             var col = circle.Colour.TopLeft.Linear;
-            colouredComponents.Colour = ColourUtils.ForegroundTextColourFor(col);
+            colouredComponents.Colour = OsuColour.ForegroundTextColourFor(col);
         }
 
         protected override void Update()

osu.Game/Utils/ColourUtils.cs

@@ -1,23 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using osu.Game.Graphics;
-using osuTK.Graphics;
-
-namespace osu.Game.Utils
-{
-    public static class ColourUtils
-    {
-        /// <summary>
-        /// Returns a foreground text colour that is supposed to contrast well on top of
-        /// the supplied <paramref name="backgroundColour"/>.
-        /// </summary>
-        public static Color4 ForegroundTextColourFor(Color4 backgroundColour)
-        {
-            // formula taken from the RGB->YIQ conversions: https://en.wikipedia.org/wiki/YIQ
-            // brightness here is equivalent to the Y component in the above colour model, which is a rough estimate of lightness.
-            float brightness = 0.299f * backgroundColour.R + 0.587f * backgroundColour.G + 0.114f * backgroundColour.B;
-            return OsuColour.Gray(brightness > 0.5f ? 0.2f : 0.9f);
-        }
-    }
-}