Calculating for different device Aspect Ratios, used in Melody Jams

CoreGraphics+AspectRatio.swift

//
//  CoreGraphics+AspectRatio.swift
//  EmptySpriteKitGame
//
//  Created by Jamie Kosoy on 11/6/15.
//  Copyright © 2015 Arbitrary. All rights reserved.
//

import UIKit
import Foundation

extension CGRect {
    init(sx: CGFloat, sy: CGFloat, swidth: CGFloat, sheight: CGFloat) {
        self.init(origin: CGPoint(sx: sx, sy: sy), size: CGSize(swidth: swidth, sheight: sheight))
    }
}

extension CGPoint {
    init(sx: CGFloat, sy: CGFloat) {
        self.init(x: sx.xForIdiom(), y: sy.yForIdiom())
    }

    func pointForIdiom() -> CGPoint {
        return CGPoint(sx: self.x, sy: y)
    }
}

extension CGSize {
    init(swidth: CGFloat, sheight: CGFloat) {
        self.init(width: swidth.widthForIdiom(), height: sheight.heightForIdiom())
    }

    func sizeForIdiom() -> CGSize {
        return CGSize(swidth: self.width, sheight: self.height)
    }

    // http://stackoverflow.com/questions/6278876/how-to-know-the-image-size-after-applying-aspect-fit-for-the-image-in-an-uiimage
    static func aspectFit(aspectRatio: CGSize, inout boundingSize: CGSize) -> CGSize {
        let mW = boundingSize.width / aspectRatio.width;
        let mH = boundingSize.height / aspectRatio.height;

        if( mH < mW ) {
            boundingSize.width = boundingSize.height / aspectRatio.height * aspectRatio.width;
        }
        else if( mW < mH ) {
            boundingSize.height = boundingSize.width / aspectRatio.width * aspectRatio.height;
        }
        
        return boundingSize;
    }
    
    static func aspectFill(aspectRatio: CGSize, inout minimumSize: CGSize) -> CGSize {
        let mW = minimumSize.width / aspectRatio.width;
        let mH = minimumSize.height / aspectRatio.height;

        if( mH > mW ) {
            minimumSize.width = minimumSize.height / aspectRatio.height * aspectRatio.width;
        }
        else if( mW > mH ) {
            minimumSize.height = minimumSize.width / aspectRatio.width * aspectRatio.height;
        }
        
        return minimumSize;
    }
}


extension CGFloat {
    private static let WidthRatio: CGFloat = 1024 / 568
    private static let HeightRatio: CGFloat = 768 / 320
    private static let PadIdiomXOffset: CGFloat = ((568 * HeightRatio) - 1024) / 2
    static let iPadAspectRatio = HeightRatio

    func widthForIdiom() -> CGFloat {
        switch UIDevice.currentDevice().userInterfaceIdiom {
        case .Pad:
            return self * CGFloat.HeightRatio
            
        default:
            return self
        }
    }
    
    func heightForIdiom() -> CGFloat {
        switch UIDevice.currentDevice().userInterfaceIdiom {
        case .Pad:
            return self * CGFloat.HeightRatio
            
        default:
            return self
        }
    }

    func xForIdiom() -> CGFloat {
        switch UIDevice.currentDevice().userInterfaceIdiom {
        case .Pad:
            return (self * CGFloat.HeightRatio) - CGFloat.PadIdiomXOffset
            
        default:
            return self
        }
    }

    func yForIdiom() -> CGFloat {
        switch UIDevice.currentDevice().userInterfaceIdiom {
        case .Pad:
            return self * CGFloat.HeightRatio
            
        default:
            return self
        }
    }
}