iPhone is designed on the assumption that it will be in the vertical direction, the screen configuration of the app, such as the position of the button is also based on vertical layout. However, when the iPhone orientation becomes horizontally, the screen rotates 90 degrees, there is also an app that changes to a horizontal layout. Speaking of iOS standard apps, Safari, email, calendar, etc. support horizontal display.
The iOS app is based on a screen design system called “auto layout” that makes it available on devices with different screen sizes and resolutions. Automatic change of screen layout according to the direction of the terminal also uses this auto layout mechanism.
However, horizontal layout is not required and not all apps support it. Even in apps that are standard on iOS, “Clock” and “Healthcare” are only vertical layouts, and the screen does not rotate even if you switch them horizontally. Similarly, the state that the app is not started (home screen) is also supported only for vertical layout.
The mechanism of the control center and notification center when it is displayed is also in line with this autolayout. If the app supports the horizontal layout, you can see the control center and flick down the upper right of the screen as in the case of vertical layout (in the case of iPhone X or later without a home button), but nothing happens in the corresponding app, it will be the same as the operation when you have it vertically.
This means that Safari, mail, and calendars can be viewed in the control center with a horizontal layout when they are landscape, and you won’t be able to see your watch or health care. It is a story that can be seen if you look at whether the layout is horizontal or vertical, so you forget just to operate the iPhone while lying down, just in case.
The Control Center can also be viewed when it’s sideways, but it’s up to the app.