     }
 }
 
-public class Stroke {
-    public var points: NSMutableArray!
-    public var properties: BrushProperties!
+private class Stroke {
+    private var points: NSMutableArray!
+    private var properties: BrushProperties!
     
     init() {
         points = []

//

public protocol TouchDrawViewDelegate {
    
    // Undo button
    func undoEnabled()
    func undoDisabled()

        tempImageView.image = nil
    }
    
    internal func popDrawing() {
        let stroke = stack.last
        stack.popLast()
        redrawLinePathsInStack()
        undoManager?.registerUndoWithTarget(self, selector: "pushDrawing:", object: stroke)
    }
    
    internal func pushDrawing(object: AnyObject) {
        let stroke = object as? Stroke
        stack.append(stroke!)
        drawLine(stroke!)
