内部类用于传递布局选项给GUILayout函数。你不要直接使用这些，而是在GUILayout类布局函数中构造它们。

参见：GUILayout.Width, GUILayout.Height, GUILayout.MinWidth, GUILayout.MaxWidth, GUILayout.MinHeight, GUILayout.MaxHeight, GUILayout.ExpandWidth, GUILayout.ExpandHeight.

示例:

using UnityEngine;
using System.Collections;

public class GUITest : MonoBehaviour {

	void OnGUI () {

        if (GUILayout.Button("This is a button", GUILayout.Width(100f), GUILayout.Height(50f)))
        {

        }
	}
}