Add central color class

I didn't move _every_ color here, but most of them. The ones I left
behind are mostly just shades of gray.

Closes #126

osu.Game/Beatmaps/Drawables/BeatmapPanel.cs

@@ -28,23 +28,19 @@ namespace osu.Game.Beatmaps.Drawables
         public Action<BeatmapPanel> GainedSelection;
         public Action<BeatmapPanel> StartRequested;
 
-        Color4 deselectedColour = new Color4(20, 43, 51, 255);
-
         protected override void Selected()
         {
             base.Selected();
             GainedSelection?.Invoke(this);
 
-            background.ColourInfo = ColourInfo.GradientVertical(
+            background.ColourInfo = OsuColor.BeatmapPanelSelected;
-                new Color4(20, 43, 51, 255),
-                new Color4(40, 86, 102, 255));
         }
 
         protected override void Deselected()
         {
             base.Deselected();
 
-            background.Colour = deselectedColour;
+            background.Colour = OsuColor.BeatmapPanelUnselected;
         }
 
         protected override bool OnClick(InputState state)
@@ -74,7 +70,7 @@ namespace osu.Game.Beatmaps.Drawables
                     CornerRadius = Content.CornerRadius,
                     RelativeSizeAxes = Axes.Both,
                     BlendingMode = BlendingMode.Additive,
-                    Colour = deselectedColour,
+                    Colour = OsuColor.BeatmapPanelUnselected,
                 },
                 new FlowContainer
                 {

osu.Game/Beatmaps/Drawables/BeatmapSetHeader.cs

@@ -92,6 +92,7 @@ namespace osu.Game.Beatmaps.Drawables
             preferUnicode.ValueChanged += preferUnicode_changed;
             preferUnicode_changed(preferUnicode, null);
         }
+
         private void preferUnicode_changed(object sender, EventArgs e)
         {
             title.Text = config.GetUnicodeString(beatmap.BeatmapSetInfo.Metadata.Title, beatmap.BeatmapSetInfo.Metadata.TitleUnicode);
@@ -138,19 +139,19 @@ namespace osu.Game.Beatmaps.Drawables
                             new Box
                             {
                                 RelativeSizeAxes = Axes.Both,
-                                ColourInfo = ColourInfo.GradientHorizontal(Color4.Black, new Color4(0f, 0f, 0f, 0.9f)),
+                                ColourInfo = OsuColor.BeatmapHeaderBackgroundA,
                                 Width = 0.05f,
                             },
                             new Box
                             {
                                 RelativeSizeAxes = Axes.Both,
-                                ColourInfo = ColourInfo.GradientHorizontal(new Color4(0f, 0f, 0f, 0.9f), new Color4(0f, 0f, 0f, 0.1f)),
+                                ColourInfo = OsuColor.BeatmapHeaderBackgroundB,
                                 Width = 0.2f,
                             },
                             new Box
                             {
                                 RelativeSizeAxes = Axes.Both,
-                                ColourInfo = ColourInfo.GradientHorizontal(new Color4(0f, 0f, 0f, 0.1f), new Color4(0, 0, 0, 0)),
+                                ColourInfo = OsuColor.BeatmapHeaderBackgroundC,
                                 Width = 0.05f,
                             },
                         }

osu.Game/Beatmaps/Drawables/Panel.cs

@@ -8,6 +8,7 @@ using osu.Framework.Graphics.Transformations;
 using osu.Framework.Input;
 using OpenTK;
 using OpenTK.Graphics;
+using osu.Game.Graphics;
 
 namespace osu.Game.Beatmaps.Drawables
 {
@@ -35,7 +36,7 @@ namespace osu.Game.Beatmaps.Drawables
                 RelativeSizeAxes = Axes.Both,
                 Masking = true,
                 CornerRadius = 10,
-                BorderColour = new Color4(221, 255, 255, 255),
+                BorderColour = OsuColor.PanelBorder,
             });
         }
 
@@ -84,7 +85,7 @@ namespace osu.Game.Beatmaps.Drawables
             nestedContainer.EdgeEffect = new EdgeEffect
             {
                 Type = EdgeEffectType.Glow,
-                Colour = new Color4(130, 204, 255, 150),
+                Colour = OsuColor.PanelGlowSelected,
                 Radius = 20,
                 Roundness = 10,
             };
@@ -98,7 +99,7 @@ namespace osu.Game.Beatmaps.Drawables
                 Type = EdgeEffectType.Shadow,
                 Offset = new Vector2(1),
                 Radius = 10,
-                Colour = new Color4(0, 0, 0, 100),
+                Colour = OsuColor.PanelGlowUnselected,
             };
         }
 

osu.Game/Beatmaps/Formats/BeatmapDecoder.cs

@@ -6,6 +6,7 @@ using System.Collections.Generic;
 using System.IO;
 using osu.Game.Modes.Objects;
 using OpenTK.Graphics;
+using osu.Game.Graphics;
 
 namespace osu.Game.Beatmaps.Formats
 {
@@ -44,11 +45,11 @@ namespace osu.Game.Beatmaps.Formats
 
         public virtual void ApplyColours(Beatmap b)
         {
-            List<Color4> colours = b.ComboColors ?? new List<Color4>() {
+            List<Color4> colours = b.ComboColors ?? new List<Color4> {
-                new Color4(17, 136, 170, 255),
+                OsuColor.Combo1,
-                new Color4(102,136,0, 255),
+                OsuColor.Combo2,
-                new Color4(204,102,0, 255),
+                OsuColor.Combo3,
-                new Color4(121,9,13, 255),
+                OsuColor.Combo4,
             };
 
             if (colours.Count == 0) return;

osu.Game/Graphics/OsuColor.cs

@@ -0,0 +1,62 @@
+using System;
+using OpenTK.Graphics;
+using osu.Framework.Graphics.Colour;
+
+namespace osu.Game.Graphics
+{
+    public static class OsuColor
+    {
+        public static readonly Color4 OsuPink = new Color4(255, 102, 170, 255);
+    
+        public static readonly Color4 BeatmapPanelUnselected = new Color4(20, 43, 51, 255);
+        public static readonly ColourInfo BeatmapPanelSelected = ColourInfo.GradientVertical(
+                new Color4(20, 43, 51, 255),
+                new Color4(40, 86, 102, 255));
+                
+        public static readonly ColourInfo BeatmapHeaderBackgroundA =
+            ColourInfo.GradientHorizontal(Color4.Black, new Color4(0f, 0f, 0f, 0.9f));
+        public static readonly ColourInfo BeatmapHeaderBackgroundB =
+            ColourInfo.GradientHorizontal(new Color4(0f, 0f, 0f, 0.9f), new Color4(0f, 0f, 0f, 0.1f));
+        public static readonly ColourInfo BeatmapHeaderBackgroundC =
+            ColourInfo.GradientHorizontal(new Color4(0f, 0f, 0f, 0.1f), new Color4(0, 0, 0, 0));
+
+        public static readonly Color4 PanelBorder = new Color4(221, 255, 255, 255);
+        public static readonly Color4 PanelGlowSelected = new Color4(130, 204, 255, 150);
+        public static readonly Color4 PanelGlowUnselected = new Color4(0, 0, 0, 100);
+
+        public static readonly Color4 Combo1 = new Color4(17, 136, 170, 255);
+        public static readonly Color4 Combo2 = new Color4(102, 136, 0, 255);
+        public static readonly Color4 Combo3 = new Color4(204, 102, 0, 255);
+        public static readonly Color4 Combo4 = new Color4(121, 9, 13, 255);
+
+        public static readonly Color4 BackButtonLeft = new Color4(195, 40, 140, 255);
+        public static readonly Color4 BackButtonRight = new Color4(238, 51, 153, 255);
+
+        public static readonly Color4 Button = new Color4(14, 132, 165, 255);
+
+        public static readonly Color4 PlayButton = new Color4(238, 51, 153, 255);
+
+        public static readonly Color4 MusicControllerBackground = new Color4(150, 150, 150, 255);
+        public static readonly Color4 MusicControllerProgress = new Color4(255, 204, 34, 255);
+
+        public static readonly Color4 CheckBoxHover = new Color4(255, 221, 238, 255);
+        public static readonly Color4 CheckBoxGlow = new Color4(187, 17, 119, 0);
+
+        public static readonly Color4 DropDownBackground = new Color4(0, 0, 0, 128);
+        public static readonly Color4 DropDownHover = new Color4(187, 17, 119, 255);
+
+        public static readonly Color4 OptionSectionHeader = new Color4(247, 198, 35, 255);
+
+        public static readonly Color4 SidebarButtonBackground = new Color4(60, 60, 60, 255);
+        public static readonly Color4 SidebarButtonSelectionIndicator = new Color4(247, 198, 35, 255);
+
+        public static readonly Color4 SliderbarBackground = new Color4(255, 102, 170, 255);
+        public static readonly Color4 SliderbarNub = new Color4(255, 102, 170, 255);
+
+        public static readonly Color4 ToolbarModeButtonIcon = new Color4(255, 194, 224, 255);
+        public static readonly Color4 ToolbarModeButtonIconActiveGlow = new Color4(255, 194, 224, 100);
+
+        public static readonly Color4 BeatmapInfoWedgeBorder = new Color4(221, 255, 255, 255);
+        public static readonly Color4 BeatmapInfoWedgeGlow = new Color4(130, 204, 255, 150);
+    }
+}

osu.Game/Graphics/UserInterface/BackButton.cs

@@ -46,7 +46,7 @@ namespace osu.Game.Graphics.UserInterface
                         leftBox = new Box
                         {
                             RelativeSizeAxes = Axes.Both,
-                            Colour = new Color4(195, 40, 140, 255),
+                            Colour = OsuColor.BackButtonLeft,
                             Shear = new Vector2(shear, 0),
                         },
                         icon = new TextAwesome
@@ -67,7 +67,7 @@ namespace osu.Game.Graphics.UserInterface
                     {
                         rightBox = new Box
                         {
-                            Colour = new Color4(238, 51, 153, 255),
+                            Colour = OsuColor.BackButtonRight,
                             Origin = Anchor.TopLeft,
                             Anchor = Anchor.TopLeft,
                             RelativeSizeAxes = Axes.Both,

osu.Game/Graphics/UserInterface/OsuButton.cs

@@ -12,7 +12,7 @@ namespace osu.Game.Graphics.UserInterface
         public OsuButton()
         {
             Height = 25;
-            Colour = new Color4(14, 132, 165, 255);
+            Colour = OsuColor.Button;
         }
     }
 }

osu.Game/Modes/Objects/HitObject.cs

@@ -4,6 +4,7 @@
 using osu.Game.Beatmaps;
 using osu.Game.Beatmaps.Samples;
 using OpenTK.Graphics;
+using osu.Game.Graphics;
 
 namespace osu.Game.Modes.Objects
 {
@@ -17,7 +18,7 @@ namespace osu.Game.Modes.Objects
 
         public bool NewCombo { get; set; }
 
-        public Color4 Colour = new Color4(17, 136, 170, 255);
+        public Color4 Colour = OsuColor.Combo1;
 
         public double Duration => EndTime - StartTime;
 

osu.Game/Online/Chat/Drawables/ChatLine.cs

@@ -35,7 +35,7 @@ namespace osu.Game.Online.Chat.Drawables
                         {
                             Text = Message.Timestamp.LocalDateTime.ToLongTimeString(),
                             TextSize = text_size,
-                            Colour = new Color4(128, 128, 128, 255)
+                            Colour = Color4.Gray
                         },
                         new SpriteText
                         {

osu.Game/Overlays/MusicController.cs

@@ -171,7 +171,7 @@ namespace osu.Game.Overlays
                     Origin = Anchor.BottomCentre,
                     Anchor = Anchor.BottomCentre,
                     Height = 10,
-                    Colour = new Color4(255, 204, 34, 255),
+                    Colour = OsuColor.MusicControllerProgress,
                     SeekRequested = seek
                 }
             };
@@ -393,7 +393,7 @@ namespace osu.Game.Overlays
                 {
                     sprite = new Sprite
                     {
-                        Colour = new Color4(150, 150, 150, 255),
+                        Colour = OsuColor.MusicControllerBackground,
                         FillMode = FillMode.Fill,
                     },
                     new Box

osu.Game/Overlays/Options/CheckBoxOption.cs

@@ -16,6 +16,7 @@ using osu.Framework.Graphics.UserInterface;
 using OpenTK;
 using OpenTK.Graphics;
 using osu.Framework.Input;
+using osu.Game.Graphics;
 
 namespace osu.Game.Overlays.Options
 {
@@ -141,21 +142,17 @@ namespace osu.Game.Overlays.Options
 
             const float border_width = 3;
 
-            Color4 hoverColour = new Color4(255, 221, 238, 255);
-            Color4 defaultColour = new Color4(255, 102, 170, 255);
-            Color4 glowColour = new Color4(187, 17, 119, 0);
-
             public Light()
             {
                 Size = new Vector2(40, 12);
 
                 Masking = true;
 
-                Colour = defaultColour;
+                Colour = OsuColor.OsuPink;
 
                 EdgeEffect = new EdgeEffect
                 {
-                    Colour = glowColour,
+                    Colour = OsuColor.CheckBoxGlow,
                     Type = EdgeEffectType.Glow,
                     Radius = 10,
                     Roundness = 8,
@@ -182,13 +179,13 @@ namespace osu.Game.Overlays.Options
                 {
                     if (value)
                     {
-                        FadeColour(hoverColour, 500, EasingTypes.OutQuint);
+                        FadeColour(OsuColor.CheckBoxHover, 500, EasingTypes.OutQuint);
                         FadeGlowTo(1, 500, EasingTypes.OutQuint);
                     }
                     else
                     {
                         FadeGlowTo(0, 500);
-                        FadeColour(defaultColour, 500);
+                        FadeColour(OsuColor.OsuPink, 500);
                     }
                 }
             }

osu.Game/Overlays/Options/DropdownOption.cs

@@ -131,8 +131,8 @@ namespace osu.Game.Overlays.Options
 
         private class StyledDropDownComboBox : DropDownComboBox
         {
-            protected override Color4 BackgroundColour => new Color4(0, 0, 0, 128);
+            protected override Color4 BackgroundColour => OsuColor.DropDownBackground;
-            protected override Color4 BackgroundColourHover => new Color4(187, 17, 119, 255);
+            protected override Color4 BackgroundColourHover => OsuColor.DropDownHover;
 
             private SpriteText label;
             protected override string Label
@@ -161,9 +161,9 @@ namespace osu.Game.Overlays.Options
 
         private class StyledDropDownMenuItem<U> : DropDownMenuItem<U>
         {
-            protected override Color4 BackgroundColour => new Color4(0, 0, 0, 128);
+            protected override Color4 BackgroundColour => OsuColor.DropDownBackground;
-            protected override Color4 BackgroundColourSelected => new Color4(0, 0, 0, 128);
+            protected override Color4 BackgroundColourSelected => OsuColor.DropDownBackground;
-            protected override Color4 BackgroundColourHover => new Color4(187, 17, 119, 255);
+            protected override Color4 BackgroundColourHover => OsuColor.DropDownHover;
         
             public StyledDropDownMenuItem(string text, U value) : base(text, value)
             {

osu.Game/Overlays/Options/OptionsSection.cs

@@ -51,7 +51,7 @@ namespace osu.Game.Overlays.Options
                         new SpriteText
                         {
                             TextSize = headerSize,
-                            Colour = new Color4(247, 198, 35, 255),
+                            Colour = OsuColor.OptionSectionHeader,
                             Text = Header,
                         },
                         content = new FlowContainer

osu.Game/Overlays/Options/SidebarButton.cs

@@ -59,7 +59,7 @@ namespace osu.Game.Overlays.Options
                     {
                         RelativeSizeAxes = Axes.Both,
                         BlendingMode = BlendingMode.Additive,
-                        Colour = new Color4(60, 60, 60, 255),
+                        Colour = OsuColor.SidebarButtonBackground,
                         Alpha = 0,
                     },
                     new Container
@@ -88,7 +88,7 @@ namespace osu.Game.Overlays.Options
                         Width = 5,
                         Anchor = Anchor.CentreRight,
                         Origin = Anchor.CentreRight,
-                        Colour = new Color4(247, 198, 35, 255)
+                        Colour = OsuColor.SidebarButtonSelectionIndicator
                     }
             };
         }

osu.Game/Overlays/Options/SliderOption.cs

@@ -16,6 +16,7 @@ using osu.Framework.Graphics.Sprites;
 using osu.Framework.Graphics.Transformations;
 using osu.Framework.Graphics.UserInterface;
 using osu.Framework.Input;
+using osu.Game.Graphics;
 
 namespace osu.Game.Overlays.Options
 {
@@ -84,7 +85,7 @@ namespace osu.Game.Overlays.Options
                         RelativeSizeAxes = Axes.None,
                         Anchor = Anchor.CentreLeft,
                         Origin = Anchor.CentreLeft,
-                        Colour = new Color4(255, 102, 170, 255),
+                        Colour = OsuColor.OsuPink,
                     },
                     rightBox = new Box
                     {
@@ -92,7 +93,7 @@ namespace osu.Game.Overlays.Options
                         RelativeSizeAxes = Axes.None,
                         Anchor = Anchor.CentreRight,
                         Origin = Anchor.CentreRight,
-                        Colour = new Color4(255, 102, 170, 255),
+                        Colour = OsuColor.SliderbarBackground,
                         Alpha = 0.5f,
                     },
                     nub = new Container
@@ -104,13 +105,14 @@ namespace osu.Game.Overlays.Options
                         AutoSizeAxes = Axes.None,
                         RelativeSizeAxes = Axes.None,
                         Masking = true,
-                        BorderColour = new Color4(255, 102, 170, 255),
+                        BorderColour = OsuColor.SliderbarNub,
                         BorderThickness = 3,
                         Children = new[]
                         {
                             new Box
                             {
-                                Colour = new Color4(255, 102, 170, 0),
+                                Colour = new Color4(OsuColor.SliderbarNub.R,
+                                    OsuColor.SliderbarNub.G, OsuColor.SliderbarNub.B, 0),
                                 RelativeSizeAxes = Axes.Both
                             }
                         }

osu.Game/Overlays/OptionsOverlay.cs

@@ -23,6 +23,7 @@ using osu.Game.Overlays.Options.Graphics;
 using osu.Game.Overlays.Options.Input;
 using osu.Game.Overlays.Options.Online;
 using System;
+using osu.Game.Graphics;
 
 namespace osu.Game.Overlays
 {
@@ -94,7 +95,7 @@ namespace osu.Game.Overlays
                                 },
                                 new SpriteText
                                 {
-                                    Colour = new Color4(255, 102, 170, 255),
+                                    Colour = OsuColor.OsuPink,
                                     Text = "Change the way osu! behaves",
                                     TextSize = 18,
                                     Margin = new MarginPadding { Left = CONTENT_MARGINS, Bottom = 30 },

osu.Game/Overlays/Toolbar/ToolbarModeButton.cs

@@ -35,7 +35,7 @@ namespace osu.Game.Overlays.Toolbar
                     DrawableIcon.EdgeEffect = new EdgeEffect
                     {
                         Type = EdgeEffectType.Glow,
-                        Colour = new Color4(255, 194, 224, 100),
+                        Colour = OsuColor.ToolbarModeButtonIconActiveGlow,
                         Radius = 15,
                         Roundness = 15,
                     };
@@ -43,7 +43,7 @@ namespace osu.Game.Overlays.Toolbar
                 else
                 {
                     DrawableIcon.Masking = false;
-                    DrawableIcon.Colour = new Color4(255, 194, 224, 255);
+                    DrawableIcon.Colour = OsuColor.ToolbarModeButtonIcon;
                 }
             }
         }

osu.Game/Overlays/Toolbar/ToolbarModeSelector.cs

@@ -13,6 +13,7 @@ using osu.Game.Graphics.Backgrounds;
 using osu.Game.Modes;
 using OpenTK;
 using OpenTK.Graphics;
+using osu.Game.Graphics;
 
 namespace osu.Game.Overlays.Toolbar
 {
@@ -52,7 +53,7 @@ namespace osu.Game.Overlays.Toolbar
                     EdgeEffect = new EdgeEffect
                     {
                         Type = EdgeEffectType.Glow,
-                        Colour = new Color4(255, 194, 224, 100),
+                        Colour = OsuColor.ToolbarModeButtonIconActiveGlow,
                         Radius = 15,
                         Roundness = 15,
                     },

osu.Game/Screens/Select/BeatmapInfoWedge.cs

@@ -14,6 +14,7 @@ using osu.Game.Beatmaps;
 using osu.Game.Database;
 using osu.Framework.Graphics.Colour;
 using osu.Game.Beatmaps.Drawables;
+using osu.Game.Graphics;
 
 namespace osu.Game.Screens.Select
 {
@@ -29,12 +30,12 @@ namespace osu.Game.Screens.Select
         {
             Shear = wedged_container_shear;
             Masking = true;
-            BorderColour = new Color4(221, 255, 255, 255);
+            BorderColour = OsuColor.BeatmapInfoWedgeBorder;
             BorderThickness = 2.5f;
             EdgeEffect = new EdgeEffect
             {
                 Type = EdgeEffectType.Glow,
-                Colour = new Color4(130, 204, 255, 150),
+                Colour = OsuColor.BeatmapInfoWedgeGlow,
                 Radius = 20,
                 Roundness = 15,
             };

osu.Game/Screens/Select/PlaySongSelect.cs

@@ -30,6 +30,7 @@ using osu.Game.Beatmaps.Drawables;
 using osu.Game.Graphics.Containers;
 using osu.Framework.Input;
 using OpenTK.Input;
+using osu.Game.Graphics;
 
 namespace osu.Game.Screens.Select
 {
@@ -142,7 +143,7 @@ namespace osu.Game.Screens.Select
                             RelativeSizeAxes = Axes.Y,
                             Width = 100,
                             Text = "Play",
-                            Colour = new Color4(238, 51, 153, 255),
+                            Colour = OsuColor.PlayButton,
                             Action = start
                         },
                     }

osu.Game/osu.Game.csproj

@@ -231,6 +231,7 @@
     <Compile Include="Configuration\ScreenshotFormat.cs" />
     <Compile Include="Configuration\FrameSync.cs" />
     <Compile Include="Configuration\ConfineMouseMode.cs" />
+    <Compile Include="Graphics\OsuColor.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="$(SolutionDir)\osu-framework\osu.Framework\osu.Framework.csproj">