Gismo16to9.cs

using UnityEngine;
using System.Collections;

public class Gismo16to9 : MonoBehaviour {
    public void OnDrawGizmos()
    {
        var camSizeHeight = Camera.main.orthographicSize;
        var camSizeWidth = camSizeHeight * 16f / 9f;

        var leftUp = new Vector2(-camSizeWidth, camSizeHeight);
        var leftDown = new Vector2(-camSizeWidth, -camSizeHeight);
        var rightUp = new Vector2(camSizeWidth, camSizeHeight);
        var rightDown = new Vector2(camSizeWidth, -camSizeHeight);
                
        Gizmos.color = Color.white;
        Gizmos.DrawLine(leftUp, leftDown);
        Gizmos.DrawLine(leftDown, rightDown);
        Gizmos.DrawLine(rightDown, rightUp);
        Gizmos.DrawLine(rightUp, leftUp);

    }
}