Front facing camera in UIImagePickerController

问题:

I am developing the front facing camera app in iPad2 by using the UIImagePickerController.

When I capture the image it's shows as flipped from left to right.

How do I correct this?

if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) 
    {
        UIImagePickerController *imgPkr = [[UIImagePickerController alloc] init];
        imgPkr.delegate = self;
        imgPkr.sourceType = UIImagePickerControllerSourceTypeCamera;
        imgPkr.cameraDevice=UIImagePickerControllerCameraDeviceFront;


        UIImageView *anImageView=[[UIImageView alloc] initWithImage:[UIImage imageNamed:[NSString stringWithFormat:@"select%d.png",val]]];
        anImageView.frame = CGRectMake(0, 0, anImageView.image.size.width, anImageView.image.size.height);
        imgPkr.cameraOverlayView = anImageView;
        [theApp.TabViewControllerObject presentModalViewController:imgPkr animated:YES];
        [imgPkr release];
    }

回答1:

You can flip the image from the source image use this

UIImage *flippedImage = [UIImage imageWithCGImage:picture.CGImage scale:picture.scale orientation:UIImageOrientationLeftMirrored];

---

Edit: Added swift code

let flippedImage = UIImage(CGImage: picture.CGImage, scale: picture.scale, orientation:.LeftMirrored)

回答2:

I had the same problem - and the solution above only got me half the answer, because the user had to approve the mirrored image before getting to the next page of my app - where I use the captured image after flipping it.

To solve this I had to flip the camera view whenever I switch to the front facing camera:

- (IBAction)flipCamera:(id)sender {
if(cameraUI.cameraDevice == UIImagePickerControllerCameraDeviceFront)
{
    cameraUI.cameraDevice = UIImagePickerControllerCameraDeviceRear;
}
else {
    cameraUI.cameraDevice = UIImagePickerControllerCameraDeviceFront;
}
cameraUI.cameraViewTransform = CGAffineTransformScale(cameraUI.cameraViewTransform, -1,     1);     
}

---

Just to expand on this great answer, some typical complete code, Dec2013, iOS7 / Xcode5. Does everything. You just need an icon (cameraToggle.PNG in the example).

-(void)showTheDeviceCamera
    {
    if ( ! [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera] )
        return;

    // self.cameraController is a UIImagePickerController
    self.cameraController = [[UIImagePickerController alloc] init];
    self.cameraController.delegate = (id)self;
    self.cameraController.mediaTypes = @[(NSString *)kUTTypeImage];
    self.cameraController.allowsEditing = YES;
    self.cameraController.sourceType = UIImagePickerControllerSourceTypeCamera;
    [self presentViewController:self.cameraController animated:YES completion:NULL];


        // Add front-rear toggle button MANUALLY, IF NECESSARY
        // (You seem to usually get it for free, on iPhone, but
        // need to add manually on an iPad.)

        UIView *buttonView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"cameraToggle"]];
        [buttonView sizeToFit];

        buttonView.userInteractionEnabled = YES;
        [self.cameraController.view addSubview:buttonView];

        UITapGestureRecognizer *tap =
            [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(_frontRearButtonClicked) ];
        tap.numberOfTapsRequired = 1;
        [buttonView addGestureRecognizer:tap];

        // we'll add it at the top right .. could be anywhere you want
        buttonView.center = CGPointMake(
                self.cameraController.view.frame.size.width-buttonView.frame.size.width,
                3.0 * buttonView.frame.size.height
                );

    }

-(void)_frontRearButtonClicked
    {
    [UIView transitionWithView:self.cameraController.view
        duration:1.0
        options:UIViewAnimationOptionAllowAnimatedContent | UIViewAnimationOptionTransitionFlipFromLeft
        animations:^{
            if ( self.cameraController.cameraDevice == UIImagePickerControllerCameraDeviceRear )
                self.cameraController.cameraDevice = UIImagePickerControllerCameraDeviceFront;
            else
                self.cameraController.cameraDevice = UIImagePickerControllerCameraDeviceRear;
        } completion:NULL];
    }

回答3:

As the other answers, I had the same problem. As Yonatan Betzer mentioned, just flip the final image is only half the answer, because the preview image, displayed by the UIPickerController when you take a picture with the front camera, it's still inverted (mirrored).

Yonatan Betzer's anwser works great, but he did not mentioned how or where to put the action to change the camera device.

Based in some codes from internet, I created a Pod to get this wanted behavior:

https://github.com/lucasecf/LEMirroredImagePicker

After installed, you just have to call this two lines of code together with your UIImagePickerController:

self.mirrorFrontPicker = [[LEMirroredImagePicker alloc] initWithImagePicker:pickerController];
[self.mirrorFrontPicker mirrorFrontCamera];

And thats it, simply as that. You can check for more informations in the README of the github link.

回答4:

Just to add how I have just achieved this without subclassing UIImagePickerController and without adding extra buttons to the camera view.

Simply listen for this notification which is fired several times whenever the camera is changed:

[[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(cameraChanged:)
                                                 name:@"AVCaptureDeviceDidStartRunningNotification"
                                               object:nil];

Then use this method to flip the camera view:

- (void)cameraChanged:(NSNotification *)notification
{
    if(imagePicker.cameraDevice == UIImagePickerControllerCameraDeviceFront)
    {
        imagePicker.cameraViewTransform = CGAffineTransformIdentity;
        imagePicker.cameraViewTransform = CGAffineTransformScale(imagePicker.cameraViewTransform, -1,     1);
    } else {
        imagePicker.cameraViewTransform = CGAffineTransformIdentity;
    }
}

回答5:

I know this question is really old but it seems like this is a still a common problem. Just set a CGAffineTransform on the cameraViewTransform property on a UIImagePickerController object.

let picker = UIImagePickerController()
picker.cameraViewTransform = CGAffineTransformScale(picker.cameraViewTransform, -1, 1)

回答6:

Updated "bandog" answer for swift 4

let picker = UIImagePickerController()
picker.cameraViewTransform = picker.cameraViewTransform.scaledBy(x: -1, y: 1)

回答7:

Full Working Example in Swift, which answers to the initial question of this post (tested on an iPhone 5c using iOS 8.2):

        import UIKit

        class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate, UIActionSheetDelegate {

         @IBOutlet var myUIImageView: UIImageView!

         var myUIImagePickerController: UIImagePickerController!

         override func viewDidLoad() {
             super.viewDidLoad()
         }

         override func viewWillAppear(animated: Bool) {
             println("viewWillAppear(animated: Bool) method called.")
             super.viewWillAppear(animated)
             NSNotificationCenter.defaultCenter().removeObserver(self)
         }

         override func viewWillDisappear(animated: Bool) {
             println("viewWillDisappear(animated: Bool) method called.")
             super.viewWillDisappear(animated)
             NSNotificationCenter.defaultCenter().addObserver(self, selector: "cameraChanged:", name: "AVCaptureDeviceDidStartRunningNotification", object: nil)
         }

         /* UIImagePickerControllerDelegate Section */
         func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject : AnyObject]) {
              if(self.myUIImagePickerController.sourceType == UIImagePickerControllerSourceType.Camera) {
                 self.myUIImageView.image = info[UIImagePickerControllerEditedImage] as? UIImage
              } else {
                 self.myUIImageView.image = info[UIImagePickerControllerOriginalImage] as? UIImage
              }
              self.dismissViewControllerAnimated(true, completion: nil)
         }

        func imagePickerControllerDidCancel(picker: UIImagePickerController) {
            self.dismissViewControllerAnimated(true, completion: nil)
        }

        /*
        You can choose to use one of the UIResponder methods:
        touchesBegan, touchesMoved, touchesEnded etc, in order to detect the touch
        on the UIImageView.
        */
        override func touchesEnded(touches: NSSet, withEvent event: UIEvent) {
            let touch: UITouch? = touches.anyObject() as? UITouch
            if (touch?.view == myUIImageView) {
                println("myUIImageView has been tapped by the user.")
                self.takingAPictureUsingTheCamera()
            }
        }

        func takingAPictureUsingTheCamera() {
            self.myUIImagePickerController = UIImagePickerController()
            self.myUIImagePickerController.delegate = self // Set the delegate
            self.myUIImagePickerController.sourceType = UIImagePickerControllerSourceType.Camera
            self.myUIImagePickerController.cameraDevice = UIImagePickerControllerCameraDevice.Front
    //        self.myUIImagePickerController.editing = true
            self.myUIImagePickerController.allowsEditing = true
            self.presentViewController(self.myUIImagePickerController, animated: true, completion: nil)
        }

        func cameraChanged(notification: NSNotification) {
             println("cameraChanged(notification: NSNotification) method called.")
             self.myUIImagePickerController.cameraViewTransform = CGAffineTransformIdentity
             if(self.myUIImagePickerController.cameraDevice == UIImagePickerControllerCameraDevice.Front){
                 self.myUIImagePickerController.cameraViewTransform = CGAffineTransformScale(self.myUIImagePickerController.cameraViewTransform, -1, 1)
             }
        }
       }// End class

回答8:

It looks like AVCaptureDeviceDidStartRunningNotification is no longer available as a means of detecting camera device changes. Also, the cameraDevice property on UIImagePickerController doesn't work with KVO. However, it's still possible to detect camera device changes, as shown below (though long-term support for this solution isn't guaranteed as we're using KVO on a property that isn't explicitly marked as KVO-compliant).

import AVFoundation

var context = 0

override func viewDidLoad() {
    super.viewDidLoad()
    // Register for notifications
    let notificationCenter = NSNotificationCenter.defaultCenter()
    notificationCenter.addObserver(self, selector: #selector(handleCaptureSessionDidStartRunning(_:)), name: AVCaptureSessionDidStartRunningNotification, object: nil)
    notificationCenter.addObserver(self, selector: #selector(handleCaptureSessionDidStopRunning(_:)), name: AVCaptureSessionDidStopRunningNotification, object: nil)
}

deinit {
    NSNotificationCenter.defaultCenter().removeObserver(self)
}

func handleCaptureSessionDidStartRunning(notification: NSNotification) {
    guard let session = notification.object as? AVCaptureSession else { return }
    session.addObserver(self, forKeyPath: "inputs", options: [ .Old, .New ], context: &context)
}

func handleCaptureSessionDidStopRunning(notification: NSNotification) {
    guard let session = notification.object as? AVCaptureSession else { return }
    session.removeObserver(self, forKeyPath: "inputs")
}

override func observeValueForKeyPath(keyPath: String?, ofObject object: AnyObject?, change: [String : AnyObject]?, context: UnsafeMutablePointer<Void>) {
    if context == &self.context {
        if let inputs = change?[NSKeyValueChangeNewKey] as? [AnyObject], captureDevice = (inputs.first as? AVCaptureDeviceInput)?.device {
            switch captureDevice.position {
            case .Back: print("Switched to back camera")
            case .Front: print("Switched to front camera")
            case .Unspecified: break
            }
        }
    } else {
        super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context)
    }
}