gistfile1.swift

import UIKit
import Darwin

@IBDesignable
class DTWheelChart: UIView {

	@IBInspectable var days: Int = 28
	
	var shapeLayers : [CAShapeLayer]!
	
	override func layoutSubviews() {
		super.layoutSubviews()
	
		if (shapeLayers == nil)
		{
			shapeLayers = []
			
			let lineWidth : CGFloat = 10
			let center = CGPoint(x: self.bounds.size.width/2.0, y: self.bounds.size.height/2.0)
			let radius = self.bounds.size.width/2.0 - lineWidth/2.0
			let startAngle : CGFloat = 0
			let endAngle : CGFloat = 0
			
			/*
			var path = UIBezierPath(arcCenter: center, radius: radius, startAngle: startAngle-CGFloat(M_PI_2), endAngle: endAngle-CGFloat(M_PI_2), clockwise: true)
			
			var shapeLayer = CAShapeLayer()
			shapeLayer.lineWidth = lineWidth
			shapeLayer.strokeColor = UIColor.redColor().CGColor
			shapeLayer.fillColor = nil
			shapeLayer.path = path.CGPath
			shapeLayer.lineCap = kCALineCapRound
			
			self.shapeLayers.append(shapeLayer)
			self.layer.addSublayer(shapeLayer)
			*/
		
			// construct compound ring bezier path
			
			let outerRadius = self.bounds.size.width/2.0;
			let innerRadius = outerRadius - lineWidth
			let middleRadius = (outerRadius + innerRadius)/2.0;
			
			var compoundPath = UIBezierPath()
			

			// start cap
			let middleStartPoint = self.positionAtAngle(center, angle: startAngle, radius: middleRadius)
			compoundPath.addArcWithCenter(middleStartPoint, radius: lineWidth/2.0, startAngle: startAngle - CGFloat(M_PI_2) + CGFloat(M_PI), endAngle: startAngle - CGFloat(M_PI_2), clockwise: true)
			
			// outer arc
			compoundPath.addArcWithCenter(center, radius: outerRadius, startAngle: startAngle-CGFloat(M_PI_2), endAngle: endAngle-CGFloat(M_PI_2), clockwise: true)
			
			// end cap
			let middleEndPoint = self.positionAtAngle(center, angle: endAngle, radius: middleRadius)
			compoundPath.addArcWithCenter(middleEndPoint, radius: lineWidth/2.0, startAngle: endAngle-CGFloat(M_PI_2), endAngle: endAngle+CGFloat(M_PI_2), clockwise: true)
			
			// inner arc
			compoundPath.addArcWithCenter(center, radius: innerRadius, startAngle: endAngle-CGFloat(M_PI_2), endAngle: startAngle-CGFloat(M_PI_2), clockwise: false)
			
			var compoundShapeLayer = CAShapeLayer()
			compoundShapeLayer.lineWidth = 1
			compoundShapeLayer.strokeColor = UIColor.blackColor().CGColor
			compoundShapeLayer.fillColor = UIColor.greenColor().CGColor
			compoundShapeLayer.path = compoundPath.CGPath
			
			self.shapeLayers.append(compoundShapeLayer)
			self.layer.addSublayer(compoundShapeLayer)
		}
	}
	
	func positionAtAngle(center: CGPoint, angle: CGFloat, radius: CGFloat) -> CGPoint
	{
		var dx = radius * sin(angle)
		var dy = radius * cos(angle)
		
		return CGPoint(x: center.x + dx, y: center.y - dy)
	}
}