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@jaylyerly
Created June 7, 2014 23:56
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Draw the Golden Spiral in Swift
// Playground - noun: a place where people can play
import UIKit
let 𝜋 = M_PI
let ɸ = (1 + sqrt(5))/2
func drawTiles(tileCount: Int, height: Double, context: CGContext) {
let red = CGFloat(arc4random_uniform(100)) / 100.0
let green = CGFloat(arc4random_uniform(100)) / 100.0
let blue = CGFloat(arc4random_uniform(100)) / 100.0
CGContextSetRGBFillColor(context, red, green, blue, 1.0)
CGContextFillRect(context, CGRectMake(0, 0, height, height))
let arc = UIBezierPath();
let center = CGPointMake(height, height)
arc.addArcWithCenter(center,
radius: height,
startAngle: -𝜋,
endAngle: -𝜋/2 ,
clockwise: true)
arc.stroke()
let scale = 1 / ɸ
if (tileCount > 0){
CGContextRotateCTM(context, 𝜋/2 )
CGContextTranslateCTM (context, 0 , -height*(1+scale));
CGContextScaleCTM(context, scale, scale)
drawTiles( (tileCount-1), height, context)
}
}
func drawGoldenSpiral(tileCount: Int, height: Double) -> UIImage {
UIGraphicsBeginImageContext(CGSize(width: height * ɸ, height: height))
drawTiles(tileCount, height, UIGraphicsGetCurrentContext())
let spiralImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return spiralImage
}
let spiralImage = drawGoldenSpiral(12, 500.0)
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