randomCircles.playground.swift

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

import UIKit
import XCPlayground


class randomCirclesView: UIView {

    override func drawRect(rect: CGRect) {
        drawCircles()
    }
    
    
    func drawCircles(){
    
        for x in 1...100 {
            let color = randomUIColor()
            let circle = randomCircle(30...70)
            
            // set the fill
            color.setFill()
            circle.fill()
            
            var alpha:CGFloat = 0
            var white:CGFloat = 0
            
            // set the stroke from the alpha channel
            color.getWhite(&white, alpha: &alpha)
            UIColor(white: 1, alpha: alpha).setStroke()
            
            circle.stroke()
        }
        
    }
    
    
    func randomCircle(radiusRange: Range<Int>) -> UIBezierPath {
        
        let pointx = CGFloat(arc4random_uniform(UInt32(self.frame.size.width)))
        let pointy = CGFloat(arc4random_uniform(UInt32(self.frame.size.height)))
        
        let circle = UIBezierPath(
            arcCenter: CGPoint(x: pointx, y: pointy),
            radius: CGFloat(arc4random_uniform(UInt32(radiusRange.endIndex - radiusRange.startIndex)) + radiusRange.startIndex),
            startAngle: 0.0,
            endAngle: CGFloat(2 * M_PI),
            clockwise: false
        )
        
        return circle
        
    }
    
    
    func randomUIColor() -> UIColor {
        
        let color = UIColor(
            red: CGFloat(arc4random_uniform(255 - 100) + 100) / 255,
            green: CGFloat(arc4random_uniform(255 - 100)) / 255,
            blue: CGFloat(arc4random_uniform(255 - 100)) / 255,
            alpha: CGFloat(arc4random_uniform(255 - 100)) / 255
        )
        
        return color

    }
    
}


let view = randomCirclesView()
view.frame = CGRectMake(0,0,500,500)
view.backgroundColor = UIColor.darkGrayColor()

XCPShowView("Main View", view)