iOS8で、[[UIScreen mainScreen] bounds]で取得したCGRectが、orientationと関係ある
in iOS7
orientationが横の場合、
[[UIScreen mainScreen] bounds].size.width is 320
[[UIScreen mainScreen] bounds].size.height is 568
orientationが縦の場合:
[[UIScreen mainScreen] bounds].size.width is 320
[[UIScreen mainScreen] bounds].size.height is 568
in iOS8
orientationが横の場合:
[[UIScreen mainScreen] bounds].size.width is 568
[[UIScreen mainScreen] bounds].size.height is 320
orientationが縦の場合:
[[UIScreen mainScreen] bounds].size.width is 320
[[UIScreen mainScreen] bounds].size.height is 568