NGUI Unity3d : Getting Screen size via http://www.zedia.net/2013/ngui-unity3d-getting-screen-size/

DisplaySize.cs

using UnityEngine;

public class DisplaySize{
	protected static DisplaySize _instance;
	public static DisplaySize instance{
		get {
			if (_instance == null){
				_instance = new DisplaySize();
			}
			return _instance;
		}
	}
 
	public GameObject gameObject;
 
	public float width;
	public float height;
 
	public void CalculateSize(){
		UIRoot mRoot = NGUITools.FindInParents<UIRoot>(gameObject);
 
		float ratio = (float)mRoot.activeHeight / Screen.height;
 
		width = Mathf.Ceil(Screen.width * ratio);
		height = Mathf.Ceil(Screen.height * ratio);
	}
}