How to make cover flow slider

Hello, I am a beginner for programmer, and I have a question
I am trying to use Scroll Rect to develop a loop menu, and I want to make it as the picture to the menu, how should I do??

I have tried to use transform.localScale to change the Button size, but there is a "depth" problem which I don't know how to slove it?

 

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.UI;
5. using DG;
6. public class ScrollRectSnap4 : MonoBehaviour {
7.     public RectTransform panel;
8.     public Button[] bttn;
9.     public RectTransform center;
10.     public float[] distance;
11.     public float[] distReposition;
12.     private bool dragging = false;
13.     public int bttnDistance;
14.     private int minButtonNum;
15.     private int bttnLenght;
16.     public float minDistance;
17.     void Start () {
18.         bttnLenght = bttn.Length;
19.         distance = new float[bttnLenght];
20.         distReposition = new float[bttnLenght];
21.         bttnDistance = (int)Mathf.Abs(bttn[1].GetComponent<RectTransform>().anchoredPosition.x - bttn[0].GetComponent<RectTransform>().anchoredPosition.x);
22.     }
23.     void Update () {
24.         for (int i = 0; i < bttn.Length; i++) {
25.             distReposition[i] = center.transform.position.x - bttn[i].transform.position.x;
26.             distance [i] = Mathf.Abs (distReposition[i]);
27.             if (distReposition [i] > 1200) {
28.                 float curX = bttn [i].GetComponent<RectTransform> ().anchoredPosition.x;
29.                 float curY = bttn [i].GetComponent<RectTransform> ().anchoredPosition.y;
30.                 Vector2 newAnchoredPos1 = new Vector2 (curX + (bttnLenght * bttnDistance), curY);
31.                 //Debug.Log (bttn[i].name + "newAnchoredPos1:   " + newAnchoredPos1);
32.                 bttn [i].GetComponent<RectTransform> ().anchoredPosition = newAnchoredPos1;
33.             }
34.             if (distReposition [i] < -1200) {
35.                 float curX = bttn [i].GetComponent<RectTransform> ().anchoredPosition.x;
36.                 float curY = bttn [i].GetComponent<RectTransform> ().anchoredPosition.y;
37.                 Vector2 newAnchoredPos2 = new Vector2 (curX - (bttnLenght * bttnDistance), curY);
38.                 bttn [i].GetComponent<RectTransform> ().anchoredPosition = newAnchoredPos2;
39.             }
40.         }
41.         minDistance = Mathf.Min (distance);
42.         for (int a = 0; a < bttn.Length; a++) {
43.             if (minDistance == distance [a]) {
44.                 minButtonNum = a;
45.                 bttn[a].transform.localScale = Vector3.Lerp(bttn[a].transform.localScale,new Vector3(1f,1f,1f),Time.deltaTime*5);
46.             } else {
47.                 bttn[a].transform.localScale = Vector3.Lerp(bttn[a].transform.localScale,new Vector3(0.7f,0.7f,0.7f),Time.deltaTime*5);
48.             }
49.         }
50.         if (!dragging) {
51.             //LerpToBttn (minButtonNum * -bttnDistance);
52.             LerpToBttn (-bttn[minButtonNum].GetComponent<RectTransform>().anchoredPosition.x);
53.         }
54.     }
55.     void LerpToBttn (float position){
56.         //Debug.Log ("Position: " + -bttn[minButtonNum].GetComponent<RectTransform>().anchoredPosition.x);
57.         float newX = Mathf.Lerp (panel.anchoredPosition.x, position, Time.deltaTime * 5f);
58.         Vector2 newPosition = new Vector2 (newX, panel.anchoredPosition.y);
59.         panel.anchoredPosition = newPosition;
60.     }
61.     public void StartDrag(){
62.         dragging = true;
63.     }
64.     public void EndDrag(){
65.         dragging = false;
66.     }
67. }

This is the process of my menu, I have tried to make the center Image bigger than others, but I don't know how to change the farest object look smaller

 

https://github.com/rakkarage/Unity3D-CoverFlow