Take 20 screenshots a second Swift? - ios

Question

I want to take 20 screenshots a second for 3 seconds, all those added to a UIImage array that gets converted into a video.
Here is the code im using to take a screenshot:
func screenshot() {
var imageSize = CGSize.zero
let orientation = UIApplication.shared.statusBarOrientation
if UIInterfaceOrientationIsPortrait(orientation) {
imageSize = UIScreen.main.nativeBounds.size
} else {
imageSize = CGSize(width: UIScreen.main.nativeBounds.size.height, height: UIScreen.main.nativeBounds.size.width)
}
UIGraphicsBeginImageContextWithOptions(imageSize, false, 0)
for window in UIApplication.shared.windows {
window.drawHierarchy(in: window.bounds, afterScreenUpdates: true)
}
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
images.append(image!)
}
I've read the following question, though it is quiet old and i'm sure that at 20FPS for 3 seconds it can be done, but i am not sure of which would be the best way to achieve it.
Edit: Use UIScreen.main.nativeBounds.size rather than UIScreen.main.bounds.size or you will get the 'wrong' image size , and it can be quiet a pain. This is true if Display Zoom is set to Zoomed rather than standard Credit: # Christopher Pickslay

Answer 1

This worked:
var limit = 80
func capture() {
if limit > 0 {
delay(0.03) {
self.screenshot()
self.capture()
} else {
convertToVideo()
}
func screenshot() {
var imageSize = CGSize.zero
let orientation = UIApplication.shared.statusBarOrientation
if UIInterfaceOrientationIsPortrait(orientation) {
imageSize = UIScreen.main.nativeBounds.size
} else {
imageSize = CGSize(width: UIScreen.main.nativeBounds.size.height, height: UIScreen.main.nativeBounds.size.width)
}
UIGraphicsBeginImageContextWithOptions(imageSize, false, 0)
for window in UIApplication.shared.windows {
window.drawHierarchy(in: window.bounds, afterScreenUpdates: true)
}
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
images.append(image!)
limit = limit - 1
}
Delay is :
func delay(_ delay:Double, closure:#escaping ()->()) {
DispatchQueue.main.asyncAfter(
deadline: DispatchTime.now() + Double(Int64(delay * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC), execute: closure)
}