How to take a screenshot programmatically on iOS

Question

I want a screenshot of the image on the screen saved into the saved photo library.

Answer 1

This will work with swift 4.2, the screenshot will be saved in library, but please don't forget to edit the info.plist @ NSPhotoLibraryAddUsageDescription :

  @IBAction func takeScreenshot(_ sender: UIButton) {

    //Start full Screenshot
    print("full Screenshot")
    UIGraphicsBeginImageContext(card.frame.size)
    view.layer.render(in: UIGraphicsGetCurrentContext()!)
    var sourceImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    UIImageWriteToSavedPhotosAlbum(sourceImage!, nil, nil, nil)

    //Start partial Screenshot
    print("partial Screenshot")
    UIGraphicsBeginImageContext(card.frame.size)
    sourceImage?.draw(at: CGPoint(x:-25,y:-100)) //the screenshot starts at -25, -100
    var croppedImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    UIImageWriteToSavedPhotosAlbum(croppedImage!, nil, nil, nil)

}