unity控制摄像机视图大小的算法

using UnityEngine;
using System.Collections;

public class MinMap : MonoBehaviour {

// Use this for initialization
void Start () {
float ratio = (float)Screen.width / (float)Screen.height;
this.GetComponent<Camera>().rect = new Rect(( 0.8f), (1- 0.2f * ratio), 0.2f, 0.2f * ratio);
}

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

}
}