Implement KeyCounter and base Count class.

osu.Game/Graphics/UserInterface/Counter.cs

@@ -0,0 +1,74 @@
+//Copyright (c) 2007-2016 ppy Pty Ltd <contact@ppy.sh>.
+//Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    abstract class Count : AutoSizeContainer
+    {
+        private Sprite buttonSprite;
+        private Sprite glowSprite;
+        private SpriteText keySpriteText;
+        private SpriteText countSpriteText;
+
+        public override string Name { get; }
+        public bool IsCounting { get; set; }
+        public int Counts { get; private set; }
+
+        private bool isLit;
+        public bool IsLit
+        {
+            get { return isLit; }
+            set
+            {
+                if (value && !isLit && IsCounting)
+                    Counts++;
+                isLit = value;
+            }
+        }
+
+        protected Count(string name)
+        {
+            Name = name;
+        }
+
+        public override void Load()
+        {
+            base.Load();
+            Children = new Drawable[]
+            {
+                buttonSprite = new Sprite
+                {
+                    Texture = Game.Textures.Get(@"KeyCounter/key-up"),
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    Children = new Drawable[]
+                    {
+                        glowSprite = new Sprite
+                        {
+                            Texture = Game.Textures.Get(@"KeyCounter/key-glow"),
+                            Anchor = Anchor.Centre,
+                            Origin = Anchor.Centre,
+                        }
+                    }
+                },
+                keySpriteText = new SpriteText
+                {
+                    Text = Name,
+                    Anchor = Anchor.TopCentre,
+                    Origin = Anchor.TopCentre
+                },
+                countSpriteText = new SpriteText
+                {
+                    Text = Counts.ToString(),
+                    Anchor = Anchor.BottomCentre,
+                    Origin = Anchor.BottomCentre
+                }
+            };
+            glowSprite.Hide();
+        }
+    }
+}

osu.Game/Graphics/UserInterface/KeyCounter.cs

@@ -0,0 +1,17 @@
+//Copyright (c) 2007-2016 ppy Pty Ltd <contact@ppy.sh>.
+//Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Graphics.Containers;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    class KeyCounter : FlowContainer
+    {
+        public KeyCounter()
+        {
+            Direction = FlowDirection.HorizontalOnly;
+        }
+
+        public void AddKey(Count key) => base.Add(key);
+    }
+}

osu.Game/osu.Game.csproj

@@ -53,6 +53,8 @@
     <Compile Include="Graphics\Containers\OsuLargeComponent.cs" />
     <Compile Include="Graphics\Processing\RatioAdjust.cs" />
     <Compile Include="Graphics\TextAwesome.cs" />
+    <Compile Include="Graphics\UserInterface\Counter.cs" />
+    <Compile Include="Graphics\UserInterface\KeyCounter.cs" />
     <Compile Include="Online\API\APIAccess.cs" />
     <Compile Include="Online\API\APIRequest.cs" />
     <Compile Include="Online\API\OAuth.cs" />