unity中全屏背景图缩放

using UnityEngine;
using System.Collections;

public class BgPicScript : MonoBehaviour {

    // Use this for initialization
    public UITexture bg;
    void Start () {

        Debug.Log("device宽高: " + Screen.width + "_" + Screen.height);

        UIRoot root = GameObject.FindObjectOfType<UIRoot>();

        if (root != null) 
        {
            //终极大杀器 整体资源缩放比例
            float s = (float)root.activeHeight / Screen.height;
            int height =  Mathf.CeilToInt(Screen.height * s);
            int width = Mathf.CeilToInt(Screen.width * s);
          
            Debug.Log("按设计分辨率屏幕width = " + width + "_height = " + height);

            Debug.Log("背景图片的设计分辨率bgWIdth:" + bg.width + "_bgHeight:" + bg.height);

            float bgRatio = (float) bg.width / bg.height;
            float manualRatio = (float)width / height;


            if (bgRatio < manualRatio) //遇到按照屏幕高度缩放水平两边出现黑边的情况,要按照宽度来缩放背景图片
            {
                //bg.width = width;
                //bg.height = Mathf.CeilToInt(width / );

                float targetScale = (float)width / bg.width;
                bg.transform.localScale = new Vector3(targetScale,targetScale, 1);
            }
        }

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



using UnityEngine;
using System.Collections;

public class UIRootScript : MonoBehaviour {

    // Use this for initialization
    void Start () {
        AdaptiveUI();
    }
    
    // Update is called once per frame
    void Update () {
    
    }

    static private void AdaptiveUI()
    {
        int ManualWidth = 1024;
        int ManualHeight = 768;
        UIRoot uiRoot = GameObject.FindObjectOfType<UIRoot>();
        if (uiRoot != null)
        {
            if (System.Convert.ToSingle(Screen.height) / Screen.width > System.Convert.ToSingle(ManualHeight) / ManualWidth)
                uiRoot.manualHeight = Mathf.RoundToInt(System.Convert.ToSingle(ManualWidth) / Screen.width * Screen.height);
            else
                uiRoot.manualHeight = ManualHeight;
        }
        Debug.Log("uiRoot Height:" + uiRoot.manualHeight);
    }
}