Idée de méthode pour UIView 

``` Objective-C
- (void)setHorintallyCenteredInView:(UIView*)view {
    [self setXOrigin:(CGRectGetWidth(view.frame) - CGRectGetWidth(self.frame))/2.0];
    [self roundFrame];
}
```

ensuite par exemple: 

``` Objective-C
UIImageView *giftImage = [UIImageView newWithImageName:@"giftSharing.png"];
[giftImage setHorintallyCenteredInView:_scrollView];
[_scrollView addSubview:giftImage];
```
