Unity UGUI实现卡片椭圆方向滚动

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using DG.Tweening;
public class CardMove : MonoBehaviour {
 GameObject[] sprites;
 int halfSize;
 Vector2 screenCenterPos;
 public float startAngle;//中间卡牌的角度
 public float deltaAngle;//相邻卡牌的角度差值
 public float moveSpeed;//移动动画的速度

 public Vector3 center;//椭圆中心点
 public float A = 1;//long axis
 public float B = 1;//short axis
 int cardcount;
 // Use this for initialization
 void Start () {
  init ();
 }

 // Update is called once per frame
 void Update () {

 }
 /// <summary>
 /// 初始化卡牌显示位置
 /// </summary>
 void init(){
  screenCenterPos = new Vector2 (Screen.width*0.5f,Screen.height*0.5f);
  cardcount = transform.childCount;
   halfSize = (cardcount - 1) / 2;
  sprites=new GameObject[cardcount];
  for (int i = 0; i < cardcount; i++) {
   sprites [i] = transform.GetChild (i).gameObject;
   setPosition (i,false);
   setDeeps (i);

  }

 }
 /// <summary>
 /// 椭圆的半长轴为A，半短轴为B，计算椭圆上一点的位置
 /// x=A*cos(angle),y=B*sin(angle)
 /// </summary>
 /// <param name="index">Index.</param>
 /// <param name="userTweener">是否使用tween动画.</param>
 void setPosition(int index,bool userTweener=true){
  //计算每一张卡片在椭圆上相对中间卡牌的角度
  float angle = 0;
  if(index<halfSize){//left
   angle=startAngle-(halfSize-index)*deltaAngle;

  }else if(index>halfSize){//right

   angle = startAngle + (index - halfSize) * deltaAngle;
  }else{//medim
   angle=startAngle;
  }


  //通过卡牌的角度，计算对应的位置
  float xpos = A*Mathf.Cos((angle/180)*Mathf.PI);//+center.x;
  float ypos = B*Mathf.Sin((angle/180)*Mathf.PI);//+center.y;
  Debug.Log ("index="+index+",xpos="+xpos+",ypos="+ypos);

  Vector2 pos = new Vector2 (xpos,ypos);
//  Debug.Log ("screenPos="+screenPos+",wordPos="+wordPos);

//通过doTween控制卡片移动动画
  if(!userTweener){
   sprites [index].GetComponent<Image> ().rectTransform.DOMove(new Vector2(screenCenterPos.x+pos.x,screenCenterPos.y+pos.y),0f);
  }else
   sprites [index].GetComponent<Image> ().rectTransform.DOMove(new Vector2(screenCenterPos.x+pos.x,screenCenterPos.y+pos.y),1f);

 }
 /// <summary>
 /// 计算每一张卡片的层级
 /// </summary>
 /// <param name="index">Index.</param>
 void setDeeps(int index){
  int deep = 0;
  if (index < halfSize) {//左侧卡牌层级，从左侧到中间，层级依此递增
   deep=index;
  } else if (deep > halfSize) {//右侧卡牌层级，从中间到右侧，层级依此递减
   deep=sprites.Length-(index+1);
  } else {
   deep = halfSize;
  }

  sprites [index].GetComponent<RectTransform> ().SetSiblingIndex (deep);
 }
 /// <summary>
 /// 左侧按钮点击，向左移动
 /// </summary>
 public void OnLeftBtnClick(){
  int length = sprites.Length;

  GameObject temp=sprites[0];
  for (int i = 0; i < length; i++) {//移动卡片在数组中的位置，依此向前移动一位
   if (i == length - 1)
    sprites [i] = temp;
   else
    sprites [i] = sprites [i + 1];
  }

  for (int i = 0; i < length; i++) {//跟新数组卡片需要显示的位置和层级
   setPosition (i);
   setDeeps (i);
  }
 }

 /// <summary>
 /// 右侧按钮点击，向右移动
 /// </summary>
 public void RightBtnClick(){
  int length = sprites.Length;

  GameObject temp=sprites[length-1];
  for (int i = length-1; i >=0; i--) {
   if (i == 0)
    sprites [i] = temp;
   else
    sprites [i] = sprites [i - 1];
  }
  for (int i = 0; i < length; i++) {
   setPosition (i);
   setDeeps (i);
  }
 }
}