Stitch multiple images together horizontally (Swift 3) - ios

Question

I want to stitch multiple images together horizontally and save it as one image. Under this question I found this suggested solution:
import UIKit
import AVFoundation
func stitchImages(images: [UIImage], isVertical: Bool) -> UIImage {
var stitchedImages : UIImage!
if images.count > 0 {
var maxWidth = CGFloat(0), maxHeight = CGFloat(0)
for image in images {
if image.size.width > maxWidth {
maxWidth = image.size.width
}
if image.size.height > maxHeight {
maxHeight = image.size.height
}
}
var totalSize : CGSize
let maxSize = CGSize(width: maxWidth, height: maxHeight)
if isVertical {
totalSize = CGSize(width: maxSize.width, height: maxSize.height * (CGFloat)(images.count))
} else {
totalSize = CGSize(width: maxSize.width * (CGFloat)(images.count), height: maxSize.height)
}
UIGraphicsBeginImageContext(totalSize)
for image in images {
let offset = (CGFloat)(images.index(of: image)!)
let rect = AVMakeRect(aspectRatio: image.size, insideRect: isVertical ?
CGRect(x: 0, y: maxSize.height * offset, width: maxSize.width, height: maxSize.height) :
CGRect(x: maxSize.width * offset, y: 0, width: maxSize.width, height: maxSize.height))
image.draw(in: rect)
}
stitchedImages = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
}
return stitchedImages
}
However, I don't know how to use it. Can someone make an example on how to use this with an array of images?
Thank you!

Answer 1

a little update with
Swift 4
extension Array where Element: UIImage {
func stitchImages(isVertical: Bool) -> UIImage {
let maxWidth = self.compactMap { $0.size.width }.max()
let maxHeight = self.compactMap { $0.size.height }.max()
let maxSize = CGSize(width: maxWidth ?? 0, height: maxHeight ?? 0)
let totalSize = isVertical ?
CGSize(width: maxSize.width, height: maxSize.height * (CGFloat)(self.count))
: CGSize(width: maxSize.width * (CGFloat)(self.count), height: maxSize.height)
let renderer = UIGraphicsImageRenderer(size: totalSize)
return renderer.image { (context) in
for (index, image) in self.enumerated() {
let rect = AVMakeRect(aspectRatio: image.size, insideRect: isVertical ?
CGRect(x: 0, y: maxSize.height * CGFloat(index), width: maxSize.width, height: maxSize.height) :
CGRect(x: maxSize.width * CGFloat(index), y: 0, width: maxSize.width, height: maxSize.height))
image.draw(in: rect)
}
}
}
}

Answer 2

Seriously?
The code you found is EXACTLY what you're looking for, but you don't know how to call it?
If you can't figure out how to call a function it's a bit hard to help you in a way that will be useful. Here's some general code that would load an array of images and stitch them together:
//Create an array of image names
let imageNames = ["Fish", "Dog", "Eggplant", "Wombat"]
//create an array of images with those names (images must exist in app bundle)
let images = imageNames.flatMap{UIImage(named:$0)}
//Stitch the images together horizontally
let stichedImage = stitchImages(images: images, isVertical: false)
You should probably stop and do some reading on Swift. I suggest downloading the Apple Swift book and reading that. It's quite good, and very easy to follow. That's how I learned the language.