unity3d中使用DoTween来控制2D摄像机视口的移动

using UnityEngine;
using System.Collections;

public class CameraMove : MonoBehaviour {

    public Camera mMapCamera;

    private float mMapWidth;
    private float mMapHeight;

    public  Transform mMapRoot;

	// Use this for initialization
	void Start () {
        mMapHeight = mMapCamera.pixelHeight;
        mMapWidth = mMapCamera.pixelWidth;
	}
	
	// Update is called once per frame
	void Update () {
	
	}

    public void MoveCameraToPosition(Vector3 pos, float time = 2.0f, Callback callback = null)
    {
        if (mMapCamera != null)
        {
            pos = Vector3.right * pos.x + Vector3.up * pos.y + Vector3.forward * mMapCamera.transform.localPosition.z;
            {
                float cameraSize = mMapCamera.orthographicSize;
                float rightX = Screen.width * cameraSize / Screen.height;
                float rightY = cameraSize;

                Vector3 cameraPos = pos;
                Vector2 maxWorldPos = new Vector2(rightX, rightY);
                Vector2 maxLocalPos = mMapRoot.InverseTransformPoint(maxWorldPos);

                float minX = maxLocalPos.x;
                float minY = maxLocalPos.y;
                float maxX = mMapWidth - maxLocalPos.x;
                float maxY = mMapHeight - maxLocalPos.y;

                float x = Mathf.Clamp(cameraPos.x, minX, maxX);
                float y = Mathf.Clamp(cameraPos.y, minY, maxY);
                float pox = x;
                float poy = y;
                if (x >= maxX)
                {
                    pox = maxX;
                }
                else if (x <= minX)
                {
                    pox = minX;
                }
                if (y >= maxY)
                {
                    poy = maxY;
                }
                else if (y <= minY)
                {
                    poy = minY;
                }
                pos = Vector3.right * pox + Vector3.up * poy + Vector3.forward * pos.z;
            }
            var tweem = mMapCamera.transform.DOLocalMove(pos, time);
            tweem.OnComplete(() =>
            {
                if (callback != null)
                {
                    callback();
                }
            });
            VerifyPosition();
        }
    }

    bool VerifyPosition()
    {
        float cameraSize = mMapCamera.orthographicSize;
        float rightX = Screen.width * cameraSize / Screen.height;
        float rightY = cameraSize;

        Vector3 cameraPos = mMapCamera.transform.localPosition;
        Vector2 maxWorldPos = new Vector2(rightX, rightY);
        Vector2 maxLocalPos = mMapRoot.InverseTransformPoint(maxWorldPos);

        float minX = maxLocalPos.x;
        float minY = maxLocalPos.y;
        float maxX = mMapWidth - maxLocalPos.x;
        float maxY = mMapHeight - maxLocalPos.y;

        float x = Mathf.Clamp(cameraPos.x, minX, maxX);
        float y = Mathf.Clamp(cameraPos.y, minY, maxY);
        mMapCamera.transform.localPosition = new Vector3(x, y, cameraPos.z);

        return x >= maxX || x <= minX || y >= maxY || y <= minY;
    }

}