GUIStyle.overflow

설명

Extra space to be added to the background image.

This is used if your image has a drop shadow and you want to extend the background image beyond the rectangles specified for gui elements that use this style.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    private RectOffset rctOff;
    void OnGUI() {
        rctOff = GUI.skin.button.overflow;
        Debug.Log("Left: " + rctOff.left + " Right: " + rctOff.right);
        Debug.Log("Top: " + rctOff.top + " Bottom: " + rctOff.bottom);
    }
}