Detect GUI rotation degree

[iast999]

Hi, I have a small project with genre fishing. Have a problem on detect rotation.
I have a GUI texture like a reel that can be rotated.

How can i make the length decrease based on each 15 degree the reel rotated?
Here is my Rotate code in C#:

public class Rotate : MonoBehaviour {

	public Texture2D texture = null;
    public Vector2 size = new Vector2(0, 0);
 
    private float angle = 0;
    private Vector2 pos = new Vector2(0, 0);
    private Rect rect;
    private Vector2 pivot;
    public static bool rotating = false;
	public static bool rotating2 = false;
    private float initialMouseAngle;
	
	static float speed = 0.1f;
	
	float factor = Screen.width/800;
 
    void Start() {
        UpdateSettings();
    }
 
    void UpdateSettings() {
       	pos = new Vector2(Screen.width-factor*700,Screen.height-factor*320+200);
        rect = new Rect(pos.x - size.x * 0.5f, pos.y - size.y * 0.5f, 150, 150);
       	//Debug.Log ("Rect="+rect);
        pivot = new Vector2(rect.xMin + rect.width * 0.5f, rect.yMin + rect.height * 0.5f);
		//Debug.Log ("Pivot ="+pivot);
    }
 
    void OnGUI() {
       	if (Application.isEditor){ 
			UpdateSettings(); 
		}
		
       	Vector2 guiMouse = Input.mousePosition;
       	guiMouse.y = Screen.height - guiMouse.y;
		
       	if (Input.GetMouseButtonDown(0) && rect.Contains(guiMouse)) {
        	Vector2 v2T = ((Vector2)guiMouse - pivot);
        	initialMouseAngle = Mathf.Atan2(v2T.y, v2T.x) - angle * Mathf.Deg2Rad;
        	rotating = true;
       	}
       	else if (Input.GetMouseButton(0) && rotating) {
         	Vector2 v2T = ((Vector2)guiMouse - pivot);
        	angle = (Mathf.Atan2 (v2T.y, v2T.x) - initialMouseAngle) * Mathf.Rad2Deg;
			//GetComponent<Length>().Jarak(speed);
			rotating2 = true;
			rect.ToString();
       	}
       	else if (Input.GetMouseButtonUp(0)) {
         	rotating = false;
			rotating2 = false;
       	}
		
        Matrix4x4 matrixBackup = GUI.matrix;
        GUIUtility.RotateAroundPivot(angle, pivot);
		
		if(FishingGUI.waktu == true){
        	GUI.DrawTexture(rect, texture);
			animation.Play("idle");
			return;
		}
		
        GUI.matrix = matrixBackup;
    }
}

I want to integrated with this want, so each 15 degree can decrease the length:

public class Length : MonoBehaviour {

	[SerializeField]
	float MaxLength = 100f;
	float CurrentLength = 0f;
	
	void Start () {
		CurrentLength = MaxLength;
	}
	
	override public string ToString(){
		return CurrentLength + "";
	}
	
	public void Jarak(float tarikans){
		CurrentLength -= tarikans;
	}
	
	void Update(){
		if(CurrentLength <= 0){
			CurrentLength = 0;
		}
	}
}

Please anyone can help or any other solution? Thanks

[sparkzbarca]

im feeling generous so here you go.

Quanternion StoredRotation;

Void Start()
{
StoredRotation = transform.rotation;
}

float Angle;
float Speed = .05f;
Void Update()
{
//anytime the GUI reel rotates it'll trigger this if statement
if(transform.rotation != StoredRotation)
{
//get the angle
Angle = Quanternion.Angle(transform.rotation, StoredRotation);

        //modify length to be equal to the angle * the speed (which can be thought of as how
`   `many
    //meters to shorten the fishing line by per degree/radians (i'm actually not sure if
    //quaternion.angle returns in degrees or radians) of change. So if you have a speed of 2
    // it'll do 2 meters presumably per 1 degree/radian which is way high 
    //so id make it a small number.)

 
LineLength = angle * speed * time.deltatime;
} 
}