kCGLineCapButt
kCGLineCapRound
kCGLineCapSquare
kCGLineJoinBevel
kCGLineJoinMiter
kCGLineJoinRound
kCGPathElementAddCurveToPoint
kCGPathElementAddLineToPoint
kCGPathElementAddQuadCurveToPoint
kCGPathElementCloseSubpath
kCGPathElementMoveToPoint