How do you display an image at the maximum available space?

Question

I check if the image is vertical or horizontal. If it is horizontal, I rotate it:

@IBOutlet private weak var img: UIImageView!

img.image = file.image    
let imageSize = file.image?.size
let imgWidth = imageSize?.width ?? 0
let imgHeight = imageSize?.height ?? 0
                    
if imgWidth > imgHeight {
    print("IMG HORIZONTAL")
    imgDetail.transform = imgDetail.transform.rotated(by: .pi / 2)
} else {
    print("IMG VERTICAL")
}

But it leaves me a space around the image. I would like it to be at the maximum size of the UIImageView.

Answer 1

Try this, declare your imageView:

let YourImageView: UIImageView = {
    let iv = UIImageView()
    iv.image = UIImage(named: "myImage")?.withRenderingMode(.alwaysOriginal)
    iv.backgroundColor = .clear
    iv.contentMode = .scaleAspectFit
    iv.isUserInteractionEnabled = true
    iv.clipsToBounds = true
    iv.translatesAutoresizingMaskIntoConstraints = false
    
    return iv
}()

in viewDidLoad set if statement and call setupConstraints:

override func viewDidLoad() {
    super.viewDidLoad()

    view.backgroundColor = .white
    
    guard let imgWidth = YourImageView.image?.size.width else { return }
    guard let imgHeight = YourImageView.image?.size.height else { return }

    if imgWidth > imgHeight {
        print("IMG HORIZONTAL")
        guard let image = YourImageView.image else { return }
        let newImage = image.rotate(radians: .pi / 2) // image rotation
        YourImageView.image = newImage
    } else {
        print("IMG VERTICAL")
    }
    
    setupConstraints()
}

set up constraints

fileprivate func setupConstraints() {
    
    view.addSubview(YourImageView)
    YourImageView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
    YourImageView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
    YourImageView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
    YourImageView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
}

write image extension

extension UIImage {
func rotate(radians: Float) -> UIImage? {
    var newSize = CGRect(origin: CGPoint.zero, size: self.size).applying(CGAffineTransform(rotationAngle: CGFloat(radians))).size
    // Trim off the extremely small float value to prevent core graphics from rounding it up
    newSize.width = floor(newSize.width)
    newSize.height = floor(newSize.height)

    UIGraphicsBeginImageContextWithOptions(newSize, false, self.scale)
    guard let context = UIGraphicsGetCurrentContext() else { return UIImage()}

    // Move origin to middle
    context.translateBy(x: newSize.width/2, y: newSize.height/2)
    // Rotate around middle
    context.rotate(by: CGFloat(radians))
    // Draw the image at its center
    self.draw(in: CGRect(x: -self.size.width/2, y: -self.size.height/2, width: self.size.width, height: self.size.height))

    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return newImage
 }
}

this is the result normal (without image rotate extension call) and rotated (with image rotate extension call):