UIImage+Extensions.swift

//
//  UIImage+Extensions.swift
//
//  Created by Daniel Tartaglia on 4/25/16.
//  Copyright © Daniel Tartaglia. MIT License.
//

import UIKit


extension UIImage {

    func imageScaledToSize(newSize: CGSize, scale: CGFloat) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(newSize, false, scale)
        self.drawInRect(CGRect(origin: CGPoint(x: 0, y: 0), size: newSize))
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage
    }

    func imageCroppedToSize(newSize: CGSize, scale: CGFloat) -> UIImage {
        let horzOffset = (self.size.width - newSize.width) / 2.0
        let vertOffset = (self.size.height - newSize.height) / 2.0
        UIGraphicsBeginImageContextWithOptions(newSize, false, scale)
        self.drawAtPoint(CGPoint(x: -horzOffset, y: -vertOffset), blendMode: .Copy, alpha: 1.0)
        let result = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return result
    }

    func imageAspectFitted(newSize: CGSize, scale: CGFloat) -> UIImage {
        let imageScaleFactor = max(newSize.width / self.size.width, newSize.height / self.size.height)
        let scaledImage = self.imageScaledToSize(CGSize(width: self.size.width * imageScaleFactor, height: self.size.height * imageScaleFactor), scale: scale)
        return scaledImage.imageCroppedToSize(newSize, scale: scale)
    }

    func squareImage() -> UIImage {
        let size = min(self.size.width, self.size.height)
        return self.imageCroppedToSize(CGSize(width: size, height: size), scale: 0)
    }

    func imageRotatedByDegrees(degrees: CGFloat, flip: Bool) -> UIImage {
        let degreesToRadians: (CGFloat) -> CGFloat = {
            return $0 / 180.0 * CGFloat(M_PI)
        }

        // calculate the size of the rotated view's containing box for our drawing space
        let rotatedViewBox = UIView(frame: CGRect(origin: CGPointZero, size: size))
        let t = CGAffineTransformMakeRotation(degreesToRadians(degrees));
        rotatedViewBox.transform = t
        let rotatedSize = rotatedViewBox.frame.size

        // Create the bitmap context
        UIGraphicsBeginImageContext(rotatedSize)
        let bitmap = UIGraphicsGetCurrentContext()

        // Move the origin to the middle of the image so we will rotate and scale around the center.
        CGContextTranslateCTM(bitmap, rotatedSize.width / 2.0, rotatedSize.height / 2.0);

        //   // Rotate the image context
        CGContextRotateCTM(bitmap, degreesToRadians(degrees));

        // Now, draw the rotated/scaled image into the context
        var yFlip: CGFloat

        if(flip){
            yFlip = CGFloat(-1.0)
        } else {
            yFlip = CGFloat(1.0)
        }

        CGContextScaleCTM(bitmap, yFlip, -1.0)
        CGContextDrawImage(bitmap, CGRectMake(-size.width / 2, -size.height / 2, size.width, size.height), CGImage)

        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return newImage
    }
}