osu-lazer/osu.Game/Graphics/UserInterface/SimpleComboCounter.cs

// Copyright (c) 2007-2017 ppy Pty Ltd <contact@ppy.sh>.
// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE

using System;
using osu.Framework.Graphics;
using osu.Framework.Graphics.Transforms;
using osu.Framework.MathUtils;

namespace osu.Game.Graphics.UserInterface
{
    /// <summary>
    /// Used as an accuracy counter. Represented visually as a percentage.
    /// </summary>
    public class SimpleComboCounter : RollingCounter<int>
    {
        protected override Type TransformType => typeof(TransformCounterCount);

        protected override double RollingDuration => 750;

        public SimpleComboCounter()
        {
            Current.Value = DisplayedCount = 0;
        }

        protected override string FormatCount(int count)
        {
            return $@"{count}x";
        }

        protected override double GetProportionalDuration(int currentValue, int newValue)
        {
            return Math.Abs(currentValue - newValue) * RollingDuration * 100.0f;
        }

        public override void Increment(int amount)
        {
            Current.Value = Current + amount;
        }

        private class TransformCounterCount : Transform<int, Drawable>
        {
            public virtual int CurrentValue
            {
                get
                {
                    double time = Time?.Current ?? 0;
                    if (time < StartTime) return StartValue;
                    if (time >= EndTime) return EndValue;

                    return (int)Interpolation.ValueAt(time, StartValue, EndValue, StartTime, EndTime, Easing);
                }
            }

            public override void Apply(Drawable d) => ((SimpleComboCounter)d).DisplayedCount = CurrentValue;
            public override void ReadIntoStartValue(Drawable d) => StartValue = ((SimpleComboCounter)d).DisplayedCount;
        }
    }
}