Question

I have a button (decrease), and when the button is pressed an arrow rotates left. I need the arrow to stop at a certain angle (approximately at 8 o’clock).

How can I get the angle of the arrow, and then stop it from rotating past this point (even if the user keeps pressing the button)?

Here’s my code:

import flash.display.MovieClip;
import flash.events.MouseEvent; 
import flash.events.Event;

stop();

var rotate = 0;  

decrease.addEventListener(MouseEvent.MOUSE_DOWN, decreasePressed);  
decrease.addEventListener(MouseEvent.MOUSE_UP, removeEnterFrame); 

function decreasePressed(e:MouseEvent):void  
{   
        rotate = -2;
        addEnterFrame();
}

function addEnterFrame():void 
{     
    this.addEventListener(Event.ENTER_FRAME, update); 
}  

function removeEnterFrame(e:MouseEvent):void 
{     
    this.removeEventListener(Event.ENTER_FRAME, update); 
}  

function update(e:Event):void 
{     
    arrow1.rotation += rotate;
} 

Answer 1

Assuming your arrow has been created vertically with the arrow pointing upwards, the 8 o’clock position when rotating anti-clockwise (as you are doing) is at approximately -112 degrees. Therefore you need to add a check in your update method to ensure that the arrow’s rotation is not set to a value lower than -112:

// May need to adjust this depending on how your arrow is created
var minDegrees = -112;

function update(e:Event):void 
{   
    var position:int = arrow1.rotation + rotate;

    // Check increment of rotation does not take us past our limit
    if (position <= minDegrees) 
         position = minDegrees;

    arrow1.rotation = position;
}