如何在UIView中处理背景图片方向

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. Eg 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;
}

Answer 2

If I understand correctly, Your background gets created or overwritten every time you change the orientation right. By default backgroundColor is nil . You can check for this, if it is nil then you go ahead and set the values. Its like

if ( self.view.backgroundColor == nil){
    //set the new values here
}   

Answer 3

You have to take 2 images both for horizontal and vertical and instead of allocating you can use [...: colorWithPatternImage:...]; and set it when orientation is changed to the background of the view.

hAPPY iCODING...