using UnityEngine;
using UnityEngine.UI;

[RequireComponent (typeof(Graphic))]
public class ImageBlinker : MonoBehaviour
{
    [SerializeField] private float speed = 7;
    [SerializeField] private float minAlpha = 0.1f;
    [SerializeField] private float maxAlpha = 0.3f;

    private Graphic graphic;
    private Color originalColor;
    void Start()
    {
        graphic = GetComponent<Graphic>();
        originalColor = graphic.color;
    }

    void Update()
    {
        float sinValue = Mathf.Sin(Time.time * speed);

        float alpha = Remap(sinValue, -1f, 1f, minAlpha, maxAlpha);

        Color color = originalColor;
        color.a = alpha;
        graphic.color = color;
    }

    float Remap(float value, float fromMin, float fromMax, float toMin, float toMax)
    {
        return toMin + (value - fromMin) * (toMax - toMin) / (fromMax - fromMin);
    }
}