Question

I’m using setting the background image using methodology below. When I rotate my device the background repeats, which make sense because it is not an image. How do I deal with orientation change if this is the way I’m setting my background image?

- (void)viewDidLoad {
    [super viewDidLoad];
    UIColor *background = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:@"background.png"]];
    self.view.backgroundColor = background;
    [background release];
}

Answer 1

It took me awhile to understand this concept. I didn’t want to create the same image portrait and landscape. The key here is that CGAffineTransformMakeRotation rotates from the original state of your UIImageView or any UIView for that matter. This assumes your background image has orientation to it. E.g. You want your UIImageView to stay put, while other objects behaves to normal orientation change event.

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation 
                                duration:(NSTimeInterval)duration {

    if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft) {  
        backgroundImage.transform = CGAffineTransformMakeRotation(M_PI / 2);
    }
    else if (toInterfaceOrientation == UIInterfaceOrientationLandscapeRight){
        backgroundImage.transform = CGAffineTransformMakeRotation(-M_PI / 2);
    }
    else {
        backgroundImage.transform = CGAffineTransformMakeRotation(0.0);
    }
}

- (void)viewDidLoad {
    [super viewDidLoad];

    //set the UIImageView to current UIView frame
    backgroundImage.frame = self.view.frame;
}