在iPad上以人像模式启动图像选择器

Question

I am using the following code to launch the image picker in my iPad app (which uses Cocos2D) :

UIImagePickerController * imagePickerController = [[UIImagePickerController alloc] init];

if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) { 

    imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
    imagePickerController.showsCameraControls = YES;
    imagePickerController.cameraCaptureMode = UIImagePickerControllerCameraCaptureModePhoto;
    imagePickerController.delegate = self;
    imagePickerController.cameraDevice = UIImagePickerControllerCameraDeviceFront;
    [self.view addSubview:imagePickerController.view];
    [self presentModalViewController:imagePickerController animated:YES];

}

I want it to launch in the portrait mode all the time, but it always launches like this :

The image appears in portrait and the image picker UI is in landscape mode. But When I capture the image, it get's rotated 90 degrees clockwise.

I want the image picker UI and the taken image, both to be in portrait mode. How can I fix this ?

Answer 1

There are three things you need to do:

1. Tell the viewController that is presenting the imagePicker to only support portrait orientation.
2. Tell the imagePicker to not to rotate the live camera feed.
3. Un-rotate captured images.

The imagePicker receives notifications of device orientation changes directly. To keep the live camera feed from rotating with the device you can stop it from receiving these notifications by telling UIDevice to endGenerating the orientation notifications after the imagePicker is presented via:

while ([currentDevice isGeneratingDeviceOrientationNotifications])
        [currentDevice endGeneratingDeviceOrientationNotifications];

The reason why you put it in a loop is because the imagePicker beginsGeneratingDeviceOrientationNotifications, and then ends its when it is dismissed, bringing the notification count on a normal device from 1 to 2 back to 1.

After the imagePicker is dismissed, you can call:

while (![currentDevice isGeneratingDeviceOrientationNotifications])
        [currentDevice beginGeneratingDeviceOrientationNotifications];

so that your ViewControllers can continue to receive orientation change notifications.

Unfortunately, even after turning this off, the images will still be saved with the correct imageOrientation of the camera on capture, so before you save the image or do anything with it, you'll have to remove the applied orientation transformation by manually countering it:

-(UIImage *)turnMeAround:(UIImage *)image{
    CGAffineTransform transform = CGAffineTransformIdentity;
    CGFloat scale = [[UIScreen mainScreen] scale]; //retina
    CGSize size = CGSizeMake(image.size.width*scale,image.size.height*scale);
    switch (image.imageOrientation) {
        case UIImageOrientationUp:
            return image;
        case UIImageOrientationDown:
            size = CGSizeMake(size.height,size.width);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
        case UIImageOrientationLeft:
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        case UIImageOrientationRight:
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;
    }
    CGContextRef context = CGBitmapContextCreate(NULL, size.width, size.height, CGImageGetBitsPerComponent(image.CGImage), 0, CGImageGetColorSpace(image.CGImage), CGImageGetBitmapInfo(image.CGImage));
    CGContextConcatCTM(context, transform);
    CGContextDrawImage(context, CGRectMake(0,0,size.width,size.height), image.CGImage);
    CGImageRef ref = CGBitmapContextCreateImage(context);
    UIImage *upsideRight = [UIImage imageWithCGImage:ref];
    CGContextRelease(context);
    CGImageRelease(ref);
    return upsideRight;
}

Answer 2

Thanks so much guys for all the help, but what worked for me is as follows :

So I found out that it was Xcode's Cocos2D template which was the culprit. It had generated the following code in the RootViewController :

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {

//
// There are 2 ways to support auto-rotation:
//  - The OpenGL / cocos2d way
//     - Faster, but doesn't rotate the UIKit objects
//  - The ViewController way
//    - A bit slower, but the UiKit objects are placed in the right place
//

#if GAME_AUTOROTATION==kGameAutorotationNone
//
// EAGLView won't be autorotated.
// Since this method should return YES in at least 1 orientation, 
// we return YES only in the Portrait orientation
//
return ( interfaceOrientation == UIInterfaceOrientationPortrait );

#elif GAME_AUTOROTATION==kGameAutorotationCCDirector
//
// EAGLView will be rotated by cocos2d
//
// Sample: Autorotate only in landscape mode
//
if( interfaceOrientation == UIInterfaceOrientationLandscapeLeft ) {
    [[CCDirector sharedDirector] setDeviceOrientation: kCCDeviceOrientationLandscapeRight];
} else if( interfaceOrientation == UIInterfaceOrientationLandscapeRight) {
    [[CCDirector sharedDirector] setDeviceOrientation: kCCDeviceOrientationLandscapeLeft];
}

// Since this method should return YES in at least 1 orientation, 
// we return YES only in the Portrait orientation
return ( interfaceOrientation == UIInterfaceOrientationPortrait );

#elif GAME_AUTOROTATION == kGameAutorotationUIViewController
//
// EAGLView will be rotated by the UIViewController
//
// Sample: Autorotate only in landscpe mode
//
// return YES for the supported orientations

return ( UIInterfaceOrientationIsLandscape( interfaceOrientation ) );

#else
#error Unknown value in GAME_AUTOROTATION

#endif // GAME_AUTOROTATION


// Shold not happen
return NO;
}

In the above code I changed this :

return ( UIInterfaceOrientationIsLandscape( interfaceOrientation ) );

To this :

return ( UIInterfaceOrientationIsPortrait( interfaceOrientation ) );

And that fixed it.