MacOS take a Screenshot with AVFoundation - swift

Question

I have Swift code:
func makeSceenshot() {
// Set up the inputs
var displayCount: UInt32 = 0;
var result = CGGetActiveDisplayList(0, nil, &displayCount)
if (result != CGError.success) {
print("error when try to get displays: \(result)")
return
}
let allocated = Int(displayCount)
let activeDisplays = UnsafeMutablePointer<CGDirectDisplayID>.allocate(capacity: allocated)
result = CGGetActiveDisplayList(displayCount, activeDisplays, &displayCount)
if (result != CGError.success) {
print("error whe try get displays list: \(result)")
return
}
for i in 1...displayCount {
// Set up the input
let display: CGDirectDisplayID = activeDisplays[Int(i-1)]
guard let input = AVCaptureScreenInput(displayID: display) else {
print("error AVCaptureScreenInput")
return
}
input.minFrameDuration = CMTimeMake(value: 1, timescale: Int32(FPS))
let session = AVCaptureSession()
if session.canAddInput(input) {
print("Input added")
session.addInput(input)
} else {
print("Input error")
}
// Set up the output
let output = AVCapturePhotoOutput()
let screenshotSettings = AVCapturePhotoSettings()
if session.canAddOutput(output) {
print("Output added")
session.addOutput(output)
} else {
print("Output error")
}
session.startRunning()
output.capturePhoto(with: screenshotSettings, delegate: self)
session.stopRunning()
}
}
}
And delegate:
extension ViewController: AVCapturePhotoCaptureDelegate {
func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
if (error != nil) {
print("\(String(describing: error?.localizedDescription)) debug: \(error.debugDescription)")
return
}
guard let imageData = photo.cgImageRepresentation() else {
print("eror")
return
}
let unixTimestamp = CreateTimeStamp()
let path = folderName + "\(unixTimestamp)" + ".jpg"
let fileUrl = URL(fileURLWithPath: path, isDirectory: true)
let bitmapRep = NSBitmapImageRep(cgImage: imageData.takeUnretainedValue())
let jpegData = bitmapRep.representation(using: NSBitmapImageRep.FileType.jpeg, properties: [:])!
do {
try jpegData.write(to: fileUrl, options: .atomic)
}
catch {print("error: \(error)")}
}
func CreateTimeStamp() -> Int32
{
return Int32(Date().timeIntervalSince1970)
}
}
And i have a problem: When i click on the Button, i need to make screenshots from all of Mac's displays. But when i click on the button, i get this message in Logs:
Optional("The operation could not be completed") debug: Optional(Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed" UserInfo={NSLocalizedDescription=The operation could not be completed, NSLocalizedFailureReason=An unknown error occurred (-11800)})
But this function
makeScreenshot()
is working if i launch it from viewDidLoad() but it doesn't launch from button action
Any ideas?

Answer 1

You can use:
let id = CGMainDisplayID()
let image = CGDisplayCreateImage(id)
Then, an alert will pop up asking the user to give your App screen recording permission. When the user adds your App to the list in the Security and Privacy Settings, CGDisplayCreateImage will capture all windows and the whole screen.