Getting a resized image from an UIImageView - ios

Question

I need to upload image data to my Parse.com backend, but I found out that my pictures are way too big, dimensions wise. NSHipster had an article on image resizing with this code:
import ImageIO
if let imageSource = CGImageSourceCreateWithURL(self.URL, nil) {
let options: CFDictionary = [
kCGImageSourceThumbnailMaxPixelSize: max(size.width, size.height) / 2.0,
kCGImageSourceCreateThumbnailFromImageIfAbsent: true
]
let scaledImage = CGImageSourceCreateThumbnailAtIndex(imageSource, 0, options).flatMap { UIImage(CGImage: $0) }
}
Unfortunately, this code does not compile in Swift 1.2. In particular there are 2 problems. The CFDictionary could not be initialized, and flatMap method was not recognized.

Answer 1

Here is some functions for resize your image:
import UIKit
func RBSquareImageTo(image: UIImage, size: CGSize) -> UIImage {
return RBResizeImage(RBSquareImage(image), size)
}
func RBSquareImage(image: UIImage) -> UIImage {
var originalWidth = image.size.width
var originalHeight = image.size.height
var edge: CGFloat
if originalWidth > originalHeight {
edge = originalHeight
} else {
edge = originalWidth
}
var posX = (originalWidth - edge) / 2.0
var posY = (originalHeight - edge) / 2.0
var cropSquare = CGRectMake(posX, posY, edge, edge)
var imageRef = CGImageCreateWithImageInRect(image.CGImage, cropSquare);
return UIImage(CGImage: imageRef, scale: UIScreen.mainScreen().scale, orientation: image.imageOrientation)
}
func RBResizeImage(image: UIImage, targetSize: CGSize) -> UIImage {
let size = image.size
let widthRatio = targetSize.width / image.size.width
let heightRatio = targetSize.height / image.size.height
// Figure out what our orientation is, and use that to form the rectangle
var newSize: CGSize
if(widthRatio > heightRatio) {
newSize = CGSizeMake(size.width * heightRatio, size.height * heightRatio)
} else {
newSize = CGSizeMake(size.width * widthRatio, size.height * widthRatio)
}
// This is the rect that we've calculated out and this is what is actually used below
let rect = CGRectMake(0, 0, newSize.width, newSize.height)
// Actually do the resizing to the rect using the ImageContext stuff
UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0)
image.drawInRect(rect)
let newImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return newImage
}
From HERE.

Answer 2

Here is the Objective C code that scale the image given by parameters.
-(UIImage*)imageWithImage:(UIImage*)image
scaledToSize:(CGSize)newSize;
{
UIGraphicsBeginImageContext( newSize );
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}