NSScreen Class Reference

Inherits from
Conforms to
Framework
/System/Library/Frameworks/AppKit.framework
Availability
Available in OS X v10.0 and later.
Companion guide
Declared in
NSScreen.h
Related sample code

Overview

An NSScreen object describes the attributes of a computer’s monitor, or screen. An application may use an NSScreen object to retrieve information about a screen and use this information to decide what to display upon that screen. For example, an application may use the deepestScreen method to find out which of the available screens can best represent color and then may choose to display all of its windows on that screen.

The application object should be created before you use the methods in this class, so that the application object can make the necessary connection to the window system. You can make sure the application object exists by invoking the sharedApplication method of NSApplication. If you created your application with Xcode, the application object is automatically created for you during initialization.

Tasks

Getting NSScreen Objects

Getting Screen Information

Screen Backing Coordinate Conversion

Class Methods

deepestScreen

Returns an NSScreen object representing the screen that can best represent color.

+ (NSScreen *)deepestScreen
Return Value

The screen with the highest bit depth.

Discussion

This method always returns an object, even if there is only one screen and it is not a color screen.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSScreen.h

mainScreen

Returns the NSScreen object containing the window with the keyboard focus.

+ (NSScreen *)mainScreen
Return Value

The main screen object.

Discussion

The main screen is not necessarily the same screen that contains the menu bar or has its origin at (0, 0). The main screen refers to the screen containing the window that is currently receiving keyboard events. It is the main screen because it is the one with which the user is most likely interacting.

The screen containing the menu bar is always the first object (index 0) in the array returned by the screens method.

Availability
  • Available in OS X v10.0 and later.
See Also
Declared In
NSScreen.h

screens

Returns an array of NSScreen objects representing all of the screens available on the system.

+ (NSArray *)screens
Return Value

An array of the NSScreen objects available on the current system or nil if the screen information could not be obtained from the window system.

Discussion

The screen at index 0 in the returned array corresponds to the primary screen of the user’s system. This is the screen that contains the menu bar and whose origin is at the point (0, 0). In the case of mirroring, the first screen is the largest drawable display; if all screens are the same size, it is the screen with the highest pixel depth. This primary screen may not be the same as the one returned by the mainScreen method, which returns the screen with the active window.

The array should not be cached. Screens can be added, removed, or dynamically reconfigured at any time. When the display configuration is changed, the default notification center sends a NSApplicationDidChangeScreenParametersNotification notification.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSScreen.h

screensHaveSeparateSpaces

Returns a Boolean value that indicates whether each screen can have its own set of spaces.

+ (BOOL)screensHaveSeparateSpaces
Discussion

This method reflects whether the “Displays have separate Spaces” option is enabled in Mission Control system preference. You might use the return value to determine how to present your app when in fullscreen mode.

Availability
  • Available in OS X v10.9 and later.
Declared In
NSScreen.h

Instance Methods

backingAlignedRect:options:

Converts a rectangle in global screen coordinates to a pixel aligned rectangle.

- (NSRect)backingAlignedRect:(NSRect)aRect options:(NSAlignmentOptions)options
Parameters
aRect

The input rectangle in global screen coordinates.

options

Specifies the alignment options. See NSAlignmentOptions for possible values.

Return Value

Returns a a pixel aligned rectangle on the target screen from the given input rectangle in global screen coordinates.

Discussion

This method uses NSIntegralRectWithOptions() to produce the pixel aligned rectangle.

Availability
  • Available in OS X v10.7 and later.
Declared In
NSScreen.h

backingScaleFactor

Returns the backing store pixel scale factor for the screen.

- (CGFloat)backingScaleFactor
Return Value

Returns the scale factor representing the number of backing store pixels corresponding to each linear unit in screen space on this NSScreen.

Discussion

This method is provided for rare cases when the explicit scale factor is needed. Please use the NSView class’s convert backing methods whenever possible.

Availability
  • Available in OS X v10.7 and later.
Declared In
NSScreen.h

colorSpace

Returns the colorSpace of the screen

- (NSColorSpace *)colorSpace
Return Value

The colorSpace of the screen.

Availability
  • Available in OS X v10.6 and later.
Declared In
NSScreen.h

convertRectFromBacking:

Converts the rectangle from the device pixel aligned coordinates system of a screen.

- (NSRect)convertRectFromBacking:(NSRect)aRect
Parameters
aRect

The rectangle.

Return Value

The rectangle converted from the device pixel aligned coordinates system of the screen.

Availability
  • Available in OS X v10.7 and later.
Declared In
NSScreen.h

convertRectToBacking:

Converts the rectangle to the device pixel aligned coordinates system of a screen.

- (NSRect)convertRectToBacking:(NSRect)aRect
Parameters
aRect

The rectangle.

Return Value

The rectangle converted to the device pixel aligned coordinates system of the screen.

Availability
  • Available in OS X v10.7 and later.
Declared In
NSScreen.h

depth

Returns the receiver’s current bit depth and colorspace information.

- (NSWindowDepth)depth
Return Value

The window depth information. This value cannot be used directly. You must pass it to a function such as NSBitsPerPixelFromDepth or NSColorSpaceFromDepth to obtain a concrete value for the desired information.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSScreen.h

deviceDescription

Returns the device dictionary for the screen.

- (NSDictionary *)deviceDescription
Return Value

A dictionary containing the attributes of the receiver's screen. For the list of keys you can use to retrieve values from the returned dictionary, see Display Device—Descriptions.

Discussion

In addition to the display device constants described in NSWindow Class Reference, you can also retrieve the CGDirectDisplayID value associated with the screen from this dictionary. To access this value, specify the Objective-C string @"NSScreenNumber" as the key when requesting the item from the dictionary. The value associated with this key is an NSNumber object containing the display ID value. This string is only valid when used as a key for the dictionary returned by this method.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSScreen.h

frame

Returns the dimensions and location of the receiver.

- (NSRect)frame
Return Value

The full screen rectangle at the current resolution. This rectangle includes any space currently occupied by the menu bar and dock.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSScreen.h

supportedWindowDepths

Returns a zero-terminated array of the window depths supported by the receiver.

- (const NSWindowDepth *)supportedWindowDepths
Return Value

A C-style array of window depths. The returned values cannot be used directly. You must pass each one to a function such as NSBitsPerPixelFromDepth or NSColorSpaceFromDepth to obtain a concrete value for the desired screen.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSScreen.h

visibleFrame

Returns the current location and dimensions of the visible screen.

- (NSRect)visibleFrame
Return Value

The rectangle defining the portion of the screen in which it is currently safe to draw your application content.

Discussion

The returned rectangle is always based on the current user-interface settings and does not include the area currently occupied by the dock and menu bar. Because it is based on the current user -interface settings, the returned rectangle can change between calls and should not be cached.

Availability
  • Available in OS X v10.0 and later.
See Also
Declared In
NSScreen.h

Notifications

NSScreenColorSpaceDidChangeNotification

Posted when the colorSpace of the screen has changed.

The notification object is the NSScreen whose colorSpace has changed.. This notification does not contain a userInfo dictionary.

Availability
Declared In
NSScreen.h