UIWindow не поворачивается при изменении ориентации устройства

Вот вам и ваше вращающееся окно, теперь вам нужно также вращать изображение, когда окно вращается. Делайте другие изменения, как хотите, я дал вам повернутое окно с поворотом устройства, просто замените ExternalVC.m следующим кодом.

    //
//  ExternalVC.m
//  Sketch
//
//  Created by mac on 21/07/18.
//  Copyright © 2018 mac. All rights reserved.
//

#import "ExternalVC.h"

@interface ExternalVC ()

@end

@implementation ExternalVC

- (void)viewDidLoad {
    [super viewDidLoad];
    self.updatedImg.image = (AppObj).updatedImg;
    NSLog(@"External window bounds:%lu",(unsigned long)self.supportedInterfaceOrientations);
    NSNotificationCenter* center = [NSNotificationCenter defaultCenter];
    [center addObserver:self selector:@selector(orientationDidChange:)
                   name:UIDeviceOrientationDidChangeNotification object:nil];

}

- (void)orientationDidChange:(NSNotification*)aNotification
{
      NSLog(@"orientation did change :%@",aNotification);
    UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation];
   // [self transformForOrientation:orientation];
    [self.view.window setTransform:[self transformForOrientation:orientation]];
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
- (UIInterfaceOrientationMask)supportedInterfaceOrientations{
    if ([UIScreen mainScreen] == (AppObj).externalWindow.screen || !(AppObj).externalWindow) {
        return UIInterfaceOrientationMaskAll;
    }else {
        return UIInterfaceOrientationMaskPortrait;
    }
}

- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator
{
    [super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];

    [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context)
     {
//         UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
     } completion:^(id<UIViewControllerTransitionCoordinatorContext> context)
     {
//
//         NSLog(@"External window bounds:%f || %f",(AppObj).externalWindow.bounds.size.width,(AppObj).externalWindow.bounds.size.height);
//    //     UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
//     //    [(AppObj).externalWindow setValue:@(orientation) forKey:@"orientation"];
////         [[UIDevice currentDevice] setValue:@(orientation) forKey:@"orientation"];
////
////
////         [UINavigationController attemptRotationToDeviceOrientation];
//         [UIViewController attemptRotationToDeviceOrientation];
//          UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation];
//        [self transformForOrientation:orientation];

     }];


}

#define DegreesToRadians(degrees) (degrees * M_PI / 180)

- (CGAffineTransform)transformForOrientation:(UIDeviceOrientation)orientation {


//        [self.view.window setFrame:CGRectMake(0, self.view.window.frame.size.height-50, self.view.window.frame.size.width, [UIScreen mainScreen].bounds.size.height)];
//        [self.view.window makeKeyAndVisible];


    switch (orientation) {

        case UIInterfaceOrientationLandscapeLeft:
            NSLog(@"UIInterfaceOrientationLandscapeLeft****");
            return CGAffineTransformMakeRotation(DegreesToRadians(90));


        case UIInterfaceOrientationLandscapeRight:
            NSLog(@"UIInterfaceOrientationLandscapeRightt****");
            return CGAffineTransformMakeRotation(-DegreesToRadians(90));

        case UIInterfaceOrientationPortraitUpsideDown:
            NSLog(@"UIInterfaceOrientationUpSideDownPortrait****");
            return CGAffineTransformMakeRotation(DegreesToRadians(180));

        case UIInterfaceOrientationPortrait:
        default:
            NSLog(@"UIInterfaceOrientationPortait****");
            return CGAffineTransformMakeRotation(DegreesToRadians(0));
    }
}

- (void)statusBarDidChangeFrame:(NSNotification *)notification {

    UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation];
    NSLog(@"status bar orientation :%ld",(long)orientation);
  //  [self.view setTransform:[self transformForOrientation:orientation]];

}
-(BOOL)shouldAutorotate{
    return YES;
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end