Space between custom UITabBar and ViewController

I took a regular `UITabBar` and changed it's background image to a custom one which has a lower height, so I changed the `height` of the `frame`. At first what I got is a blank space below the tab bar. so I changed the `origin` of the `frame` too. But now the blank space has moved up above the tab bar and this is the result: And this is the code declaring the tab bar in the AppDelegate: ``` self.tabContoller = [[UITabBarController alloc] init]; //customizing the tabbar UIImage * tabBackgroundImage = [UIImage imageNamed:@"tabBarBg.png"]; self.tabContoller.tabBar.backgroundColor = [UIColor colorWithRed:245.f/255.f green:245.f/255.f blue:245.f/255.f alpha:255.f/255.f]; self.tabContoller.tabBar.backgroundImage = tabBackgroundImage; //setting the tabbar height to the correct height of the image CGRect tabR = self.tabContoller.tabBar.frame; CGFloat diff = tabR.size.height - tabBackgroundImage.size.height; tabR.size.height = tabBackgroundImage.size.height; tabR.origin.y += diff; self.tabContoller.tabBar.frame = tabR; ``` I guess that the problem is that the `ViewController`s draw themselves above a constant space which is the height of the regular tab bar. Is there any way to change it?