FollowUIImage

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


public class PointUI : MonoBehaviour {
    public Image image;
    private List<Vector3> newListOfPoints;
    private LineRenderer line;

    // Use this for initialization
    void Start () {
        newListOfPoints = new List<Vector3>();
        Vector3[] pts = new Vector3[5];
        line = GetComponent<LineRenderer>();
        line.GetPositions(pts);
        foreach(Vector3 p in pts) {
            newListOfPoints.Add(p);
        }
    }

    // Update is called once per frame
    void Update () {
        float dist = (Camera.main.transform.position - newListOfPoints[0]).magnitude;
        Rect r = RectTransformToScreenSpace((RectTransform)image.transform);
        Vector3 v3 = new Vector3(r.xMin, r.yMin, dist);
        /*Vector2 v2 = RectTransformUtility.WorldToScreenPoint(Camera.main, image.transform.position);
        Vector3 v3 = new Vector3(v2.x, v2.y, Camera.main.nearClipPlane);*/
        Vector3 val = Camera.main.ScreenToWorldPoint(v3);

        for(int i = 0; i < newListOfPoints.Count; i++) {
            line.SetPosition(i, new Vector3(newListOfPoints[i].x, val.y, newListOfPoints[i].z));
        }
    }

    public static Rect RectTransformToScreenSpace(RectTransform transform) {
        Vector2 size = Vector2.Scale(transform.rect.size, transform.lossyScale);
        Rect rect = new Rect(transform.position.x, transform.position.y, size.x, size.y);
        rect.x -= (transform.pivot.x * size.x);
        rect.y -= ((1.0f - transform.pivot.y) * size.y);
        return rect;
    }
}