Hook up icons better.

osu.Game.Modes.Catch/CatchRuleset.cs

@@ -2,6 +2,7 @@
 //Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using System.Collections.Generic;
+using osu.Game.Graphics;
 using osu.Game.Modes.Catch.UI;
 using osu.Game.Modes.Objects;
 using osu.Game.Modes.Osu.Objects;
@@ -18,6 +19,8 @@ namespace osu.Game.Modes.Catch
 
         protected override PlayMode PlayMode => PlayMode.Catch;
 
+        public override FontAwesome Icon => FontAwesome.fa_osu_fruits_o;
+
         public override ScoreProcessor CreateScoreProcessor(int hitObjectCount) => null;
 
         public override HitObjectParser CreateHitObjectParser() => new OsuHitObjectParser();

osu.Game.Modes.Mania/ManiaRuleset.cs

@@ -2,6 +2,7 @@
 //Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using System.Collections.Generic;
+using osu.Game.Graphics;
 using osu.Game.Modes.Mania.UI;
 using osu.Game.Modes.Objects;
 using osu.Game.Modes.Osu;
@@ -19,6 +20,8 @@ namespace osu.Game.Modes.Mania
 
         protected override PlayMode PlayMode => PlayMode.Mania;
 
+        public override FontAwesome Icon => FontAwesome.fa_osu_mania_o;
+
         public override ScoreProcessor CreateScoreProcessor(int hitObjectCount) => null;
 
         public override HitObjectParser CreateHitObjectParser() => new OsuHitObjectParser();

osu.Game.Modes.Osu/OsuRuleset.cs

@@ -34,6 +34,8 @@ namespace osu.Game.Modes.Osu
             }
         };
 
+        public override FontAwesome Icon => FontAwesome.fa_osu_osu_o;
+
         public override HitObjectParser CreateHitObjectParser() => new OsuHitObjectParser();
 
         public override ScoreProcessor CreateScoreProcessor(int hitObjectCount) => new OsuScoreProcessor(hitObjectCount);

osu.Game.Modes.Taiko/TaikoRuleset.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using osu.Game.Graphics;
 using osu.Game.Modes.Objects;
 using osu.Game.Modes.Osu.Objects;
 using osu.Game.Modes.Osu.UI;
@@ -19,6 +20,8 @@ namespace osu.Game.Modes.Taiko
 
         protected override PlayMode PlayMode => PlayMode.Taiko;
 
+        public override FontAwesome Icon => FontAwesome.fa_osu_taiko_o;
+
         public override ScoreProcessor CreateScoreProcessor(int hitObjectCount) => null;
 
         public override HitObjectParser CreateHitObjectParser() => new OsuHitObjectParser();

osu.Game/Beatmaps/Drawables/BeatmapGroup.cs

@@ -74,6 +74,8 @@ namespace osu.Game.Beatmaps.Drawables
                 StartRequested = p => { StartRequested?.Invoke(p.Beatmap); },
                 RelativeSizeAxes = Axes.X,
             }).ToList();
+
+            Header.AddDifficultyIcons(BeatmapPanels);
         }
 
         private void headerGainedSelection(BeatmapSetHeader panel)

osu.Game/Beatmaps/Drawables/BeatmapPanel.cs

@@ -17,6 +17,7 @@ using osu.Game.Graphics.UserInterface;
 using OpenTK;
 using OpenTK.Graphics;
 using osu.Framework.Input;
+using osu.Game.Modes;
 
 namespace osu.Game.Beatmaps.Drawables
 {
@@ -83,7 +84,7 @@ namespace osu.Game.Beatmaps.Drawables
                     Origin = Anchor.CentreLeft,
                     Children = new Drawable[]
                     {
-                        new DifficultyIcon(FontAwesome.fa_dot_circle_o, new Color4(159, 198, 0, 255))
+                        new DifficultyIcon(beatmap)
                         {
                             Scale = new Vector2(1.8f),
                             Anchor = Anchor.CentreLeft,

osu.Game/Beatmaps/Drawables/BeatmapSetHeader.cs

@@ -2,6 +2,7 @@
 //Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
 
 using System;
+using System.Collections.Generic;
 using osu.Framework.Allocation;
 using osu.Framework.Configuration;
 using osu.Framework.Graphics;
@@ -23,6 +24,7 @@ namespace osu.Game.Beatmaps.Drawables
         private OsuConfigManager config;
         private Bindable<bool> preferUnicode;
         private WorkingBeatmap beatmap;
+        private FlowContainer difficultyIcons;
 
         public BeatmapSetHeader(WorkingBeatmap beatmap)
         {
@@ -56,15 +58,10 @@ namespace osu.Game.Beatmaps.Drawables
                             TextSize = 17,
                             Shadow = true,
                         },
-                        new FlowContainer
+                        difficultyIcons = new FlowContainer
                         {
                             Margin = new MarginPadding { Top = 5 },
                             AutoSizeAxes = Axes.Both,
-                            Children = new[]
-                            {
-                                new DifficultyIcon(FontAwesome.fa_dot_circle_o, new Color4(159, 198, 0, 255)),
-                                new DifficultyIcon(FontAwesome.fa_dot_circle_o, new Color4(246, 101, 166, 255)),
-                            }
                         }
                     }
                 }
@@ -177,5 +174,11 @@ namespace osu.Game.Beatmaps.Drawables
                 });
             }
         }
+
+        public void AddDifficultyIcons(IEnumerable<BeatmapPanel> panels)
+        {
+            foreach (var p in panels)
+                difficultyIcons.Add(new DifficultyIcon(p.Beatmap));
+        }
     }
 }

osu.Game/Beatmaps/Drawables/DifficultyIcon.cs

@@ -3,7 +3,9 @@
 
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
+using osu.Game.Database;
 using osu.Game.Graphics;
+using osu.Game.Modes;
 using OpenTK;
 using OpenTK.Graphics;
 
@@ -11,7 +13,7 @@ namespace osu.Game.Beatmaps.Drawables
 {
     class DifficultyIcon : Container
     {
-        public DifficultyIcon(FontAwesome icon, Color4 color)
+        public DifficultyIcon(BeatmapInfo beatmap)
         {
             const float size = 20;
             Size = new Vector2(size);
@@ -21,8 +23,8 @@ namespace osu.Game.Beatmaps.Drawables
                 {
                     Anchor = Anchor.Centre,
                     TextSize = size,
-                    Colour = color,
+                    Colour = new Color4(159, 198, 0, 255),
-                    Icon = icon
+                    Icon = Ruleset.GetRuleset(beatmap.Mode).Icon
                 }
             };
         }

osu.Game/Modes/Ruleset.cs

@@ -4,11 +4,8 @@
 using System.Collections.Generic;
 using osu.Game.Modes.Objects;
 using osu.Game.Modes.UI;
-using System.Reflection;
-using osu.Framework.Extensions;
 using System;
 using System.Collections.Concurrent;
-using System.Linq;
 using osu.Game.Beatmaps;
 using osu.Game.Graphics;
 
@@ -39,6 +36,8 @@ namespace osu.Game.Modes
 
         protected abstract PlayMode PlayMode { get; }
 
+        public virtual FontAwesome Icon => FontAwesome.fa_question_circle;
+
         public static Ruleset GetRuleset(PlayMode mode)
         {
             Type type;

osu.Game/Overlays/Toolbar/ToolbarModeButton.cs

@@ -3,7 +3,6 @@
 
 using osu.Framework.Extensions;
 using osu.Framework.Graphics.Containers;
-using osu.Game.Graphics;
 using osu.Game.Modes;
 using OpenTK.Graphics;
 
@@ -20,7 +19,7 @@ namespace osu.Game.Overlays.Toolbar
                 mode = value;
                 TooltipMain = mode.GetDescription();
                 TooltipSub = $"Play some {mode.GetDescription()}";
-                Icon = getModeIcon(mode);
+                Icon = Ruleset.GetRuleset(mode).Icon;
             }
         }
 
@@ -48,17 +47,6 @@ namespace osu.Game.Overlays.Toolbar
             }
         }
 
-        private FontAwesome getModeIcon(PlayMode mode)
-        {
-            switch (mode)
-            {
-                default: return FontAwesome.fa_osu_osu_o;
-                case PlayMode.Taiko: return FontAwesome.fa_osu_taiko_o;
-                case PlayMode.Catch: return FontAwesome.fa_osu_fruits_o;
-                case PlayMode.Mania: return FontAwesome.fa_osu_mania_o;
-            }
-        }
-
         protected override void LoadComplete()
         {
             base.LoadComplete();