Refactor + Stars Counter (initial)

Moved a few things to allow using common transforms
for a star counter. This implementation is basic and
hacky, but good enough as proof of concept.

osu.Game/Graphics/UserInterface/NumericRollingCounter.cs

@@ -0,0 +1,64 @@
+//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.Sprites;
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    /// <summary>
+    /// Skeleton for a numeric counter with a simple roll-up animation.
+    /// </summary>
+    /// <typeparam name="T">Type of the actual counter.</typeparam>
+    public abstract class NumericRollingCounter<T> : RollingCounter<T>
+    {
+        protected SpriteText countSpriteText;
+
+        protected float textSize = 20.0f;
+        public float TextSize
+        {
+            get { return textSize; }
+            set
+            {
+                textSize = value;
+                updateTextSize();
+            }
+        }
+
+        public override void Load()
+        {
+
+            base.Load();
+            Children = new Drawable[]
+            {
+                countSpriteText = new SpriteText
+                {
+                    Text = formatCount(Count),
+                    TextSize = this.TextSize,
+                    Anchor = this.Anchor,
+                    Origin = this.Origin,
+                },
+            };
+        }
+
+        protected override void transformVisibleCount(T currentValue, T newValue)
+        {
+            if (countSpriteText != null)
+            {
+                countSpriteText.Text = formatCount(newValue);
+            }
+        }
+
+        protected virtual void updateTextSize()
+        {
+            if (countSpriteText != null)
+                countSpriteText.TextSize = TextSize;
+        }
+    }
+}