c# - How to detect mouse over for UI image in Unity 5?

I have an image that I have setup to move around and zoom in and out from. The trouble is the zoom can be done from anywhere in the scene, but I only want it to zoom when the mouse is hovering over the image. I have tried to use OnMouseEnter, OnMouseOver, event triggers, all three of those without a collider, with a collider, with a trigger collider, and all of that on the image itself and on an empty game object. However none of those have worked...So I am absolutely stumped...Could someone help me out here!

Here is my script:

    private float zoom;
    public float zoomSpeed;

    public Image map;

    public float zoomMin;
    public float zoomMax;

    void Update () {
        zoom = (Input.GetAxis("Mouse ScrollWheel") * Time.deltaTime * zoomSpeed);
        map.transform.localScale += new Vector3(map.transform.localScale.x * zoom, map.transform.localScale.y * zoom, 0);
        Vector3 scale = map.transform.localScale;
        scale = new Vector3(Mathf.Clamp(map.transform.localScale.x, zoomMin, zoomMax), Mathf.Clamp(map.transform.localScale.y, zoomMin, zoomMax), 0);

        map.transform.localScale = scale;
    }

Answer

You can implement IPointerEnter and IPointerExit interfaces and keep boolean for 'over state':

using System;
using UnityEngine;
using UnityEngine.EventSystems;

public class TestOver : MonoBehaviour, IPointerEnterHandler, IPointerExitHandler
{

    public bool isOver = false;

    public void OnPointerEnter(PointerEventData eventData)
    {
        Debug.Log("Mouse enter");
        isOver = true;
    }

    public void OnPointerExit(PointerEventData eventData)
    {

        Debug.Log("Mouse exit");
        isOver = false;
    }
}