UIImageExtension.swift

//
//  UIImageExtension.swift
//  PicPic
//
//  Created by Johnny Pham on 6/28/16.
//  Copyright © 2016 John Pham. All rights reserved.
//

import UIKit

extension UIImage {
    var uncompressedPNGData: NSData { return UIImagePNGRepresentation(self)!        }
    var highestQualityJPEGNSData: NSData { return UIImageJPEGRepresentation(self, 1.0)!  }
    var highQualityJPEGNSData: NSData { return UIImageJPEGRepresentation(self, 0.75)! }
    var mediumQualityJPEGNSData: NSData { return UIImageJPEGRepresentation(self, 0.5)!  }
    var lowQualityJPEGNSData: NSData { return UIImageJPEGRepresentation(self, 0.25)! }
    var lowestQualityJPEGNSData: NSData { return UIImageJPEGRepresentation(self, 0.0)!  }

    func compressImage() -> NSData {
        // Reducing file size to a 10th
        let image = self as UIImage
        var actualHeight: CGFloat = image.size.height
        var actualWidth: CGFloat = image.size.width
        let maxHeight: CGFloat = IMAGE_MAX_HEIGHT
        let maxWidth: CGFloat = IMAGE_MAX_WIDTH
        var imgRatio: CGFloat = actualWidth/actualHeight
        let maxRatio: CGFloat = maxWidth/maxHeight
        let compressionQuality: CGFloat = IMAGE_COMPRESSION_QUALITY

        if (actualHeight > maxHeight || actualWidth > maxWidth) {
            if(imgRatio < maxRatio) {
                //adjust width according to maxHeight
                imgRatio = maxHeight / actualHeight
                actualWidth = imgRatio * actualWidth
                actualHeight = maxHeight
            } else if(imgRatio > maxRatio) {
                //adjust height according to maxWidth
                imgRatio = maxWidth / actualWidth
                actualHeight = imgRatio * actualHeight
                actualWidth = maxWidth
            } else {
                actualHeight = maxHeight
                actualWidth = maxWidth
            }
        }

        let rect = CGRectMake(0.0, 0.0, actualWidth, actualHeight)
        UIGraphicsBeginImageContext(rect.size)
        image.drawInRect(rect)
        let img = UIGraphicsGetImageFromCurrentImageContext()
        let imageData = UIImageJPEGRepresentation(img, compressionQuality)
        UIGraphicsEndImageContext()
        return imageData!
    }
}