Xcode playground to draw a circle

circle.playground

// Playground - noun: a place where people can play

import Cocoa
import XCPlayground

let graphWidth: CGFloat = 400.0;
let graphHeight: CGFloat = 400.0

var frameRect = NSRect(x: 0, y: 0, width: graphWidth, height: graphHeight)
var view = NSImageView(frame: frameRect)

var size = NSMakeSize( graphWidth, graphHeight )
var image = NSImage(size: size)

image.lockFocus()
let foregroundColor = NSColor.blackColor()
foregroundColor.setFill()
image.unlockFocus()

let radius :Double = 150
let center = NSMakePoint(graphWidth / 2, graphHeight / 2)
var x : Double
var y : Double
var p : NSPoint
var oldPoint : NSPoint!
var path = NSBezierPath()

for var i : Double = 0.0; i < 390; i += 10.00 {
    image.lockFocus()
    let angle : Double = i * (M_PI / 180)
    x = cos(angle) * radius + Double(center.x)
    y = sin(angle) * radius + Double(center.y)
    p = NSPoint(x: x , y: y)
    if oldPoint == nil {
        oldPoint = p
    }
    path.moveToPoint(oldPoint)
    path.lineToPoint(p)

    path.stroke()
    image.unlockFocus()
    oldPoint = p
}


var view2 = NSImageView(frame: frameRect)
view2.image = image
XCPShowView("Circle", view2)