Tween.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Tween {
    public delegate void OnUpdate(float progress);
    public delegate void OnFinish();

    MonoBehaviour mb;
    OnFinish onFinish;
    IEnumerator coroutine;

    public static IEnumerator Start(float duration, OnUpdate onUpdate, bool unscaled = false) {
        float t = 0;
        while (t < duration) {
            onUpdate(t / duration);
            t += unscaled ? Time.unscaledDeltaTime : Time.deltaTime;
            yield return null;
        }
    }

    public Tween(MonoBehaviour mb) {
        this.mb = mb;
        onFinish = () => {};
        coroutine = null;
    }

    public void Start(float duration, OnUpdate onUpdate, OnFinish onFinish, bool unscaled = false) {
        if (IsAnimating()) {
            mb.StopCoroutine(coroutine);
            coroutine = null;
        }
        this.onFinish = onFinish;
        coroutine = Animate(duration, onUpdate, onFinish, unscaled);
        mb.StartCoroutine(coroutine);
    }

    public void Stop() {
        if (IsAnimating()) {
            mb.StopCoroutine(coroutine);
            coroutine = null;
            onFinish();
        }
    }

    public bool IsAnimating() {
        return coroutine != null;
    }

    IEnumerator Animate(float duration, OnUpdate onUpdate, OnFinish onFinish, bool unscaled) {
        yield return Tween.Start(duration, onUpdate, unscaled);
        coroutine = null;
        onFinish();
    }
}