CheckBox.swift

import UIKit

class CheckBox: UIButton {

  let roundedRectStrokeColor = UIColor.GBTint()
  let roundedRectFillColor = UIColor.whiteColor()
  let checkmarkColor = UIColor.greenColor()
  
  override func drawRect(rect: CGRect) {
    super.drawRect(rect)
    
    //
    // Draw checkbox with OFF state
    //
    let lineWidth:CGFloat = rect.size.width / 10
    let roundedRect = UIBezierPath(roundedRect: CGRectInset(rect, lineWidth/2, lineWidth/2), cornerRadius: 5)
    roundedRect.lineWidth = lineWidth
    roundedRectStrokeColor.setStroke()
    roundedRect.stroke()
    roundedRectFillColor.setFill()
    roundedRect.fill()
    
    //
    // Draw checkbox with ON state
    //
    
    // Draw check mark
    if selected {
      let checkmark = UIBezierPath()
      let size = rect.size
      checkmark.moveToPoint(CGPoint(x: 22/100 * size.width, y: 52/100 * size.height))
      checkmark.addLineToPoint(CGPoint(x: 38/100 * size.width, y: 68/100 * size.height))
      checkmark.addLineToPoint(CGPoint(x: 76/100 * size.width, y: 30/100 * size.height))
      
      checkmark.lineWidth = lineWidth
      checkmarkColor.setStroke()
      checkmark.stroke()
    }
  }
}