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# QDesktopWidget Class Reference
[QtGui module]

The QDesktopWidget class provides access to screen information on multi-head systems. More...

Inherits QWidget.

### Methods

- __init__ (self)
- QRect availableGeometry (self, int screen = -1)
- QRect availableGeometry (self, QWidget widget)
- QRect availableGeometry (self, QPoint point)
- bool isVirtualDesktop (self)
- int numScreens (self)
- int primaryScreen (self)
- resizeEvent (self, QResizeEvent e)
- QWidget screen (self, int screen = -1)
- int screenCount (self)
- QRect screenGeometry (self, int screen = -1)
- QRect screenGeometry (self, QWidget widget)
- QRect screenGeometry (self, QPoint point)
- int screenNumber (self, QWidget widget = None)
- int screenNumber (self, QPoint)

### Qt Signals

- void resized (int)
- void screenCountChanged (int)
- void workAreaResized (int)

## Detailed Description

The QDesktopWidget class provides access to screen information on multi-head systems.

Systems with more than one graphics card and monitor can manage the physical screen space available either as multiple desktops, or as a large virtual desktop.

This class provides information about the user's desktop, such as its total size, number of screens, the geometry of each screen, and whether they are configured as separate desktops or a single virtual desktop.

Widgets provided by Qt use this class to place tooltips, menus and dialog boxes on the correct screen for their parent or application widgets. Applications can use this class to obtain information that can be used to save window positions, or to place child widgets and dialogs on one particular screen.

### Obtaining a Desktop Widget

The QApplication.desktop() function is used to get an instance of QDesktopWidget.

The widget's screenGeometry() function provides information about the geometry of the available screens with. The number of screens available is returned by screenCount, and the screenCountChanged() signal is emitted when screens are added or removed. The screen number that a particular point or widget is located in is returned by screenNumber().

### Screen Geometry

To obtain the dimensions of a particular screen, call the screenGeometry() function. On some desktop environments, not all of the screen is available for applications to use; for example, an application dock or menu bar may take up some space. Use the availableGeometry() function to obtain the available area for applications.

QDesktopWidget also inherits the QWidget properties, width() and height(), which specify the size of the desktop. However, for desktops with multiple screens, the size of the desktop is the union of all the screen sizes, so width() and height() should not be used for computing the size of a widget to be placed on one of the screens.

On systems that are configured to use the available screens as a single, large virtual desktop, the virtualDesktop property will be set to true. In this case, the widget's size is usually the size of the bounding rectangle of all the screens.

### Use of the Primary Screen

For an application, the screen where the main widget resides is the primary screen. This is stored in the primaryScreen property. All windows opened in the context of the application should be constrained to the boundaries of the primary screen; for example, it would be inconvenient if a dialog box popped up on a different screen, or split over two screens.

In the illustration above, Application One's primary screen is screen 0, and App Two's primary screen is screen 1.

## Method Documentation

### QDesktopWidget.__init__ (self)

### QRect QDesktopWidget.availableGeometry (self, int screen = -1)

Returns the available geometry of the screen with index screen. What is available will be subrect of screenGeometry() based on what the platform decides is available (for example excludes the dock and menu bar on Mac OS X, or the task bar on Windows). The default screen is used if screen is -1.

See also screenNumber() and screenGeometry().

### QRect QDesktopWidget.availableGeometry (self, QWidget widget)

This is an overloaded function.

Returns the available geometry of the screen which contains widget.

See also screenGeometry().

### QRect QDesktopWidget.availableGeometry (self, QPoint point)

This is an overloaded function.

Returns the available geometry of the screen which contains p.

See also screenGeometry().

### bool QDesktopWidget.isVirtualDesktop (self)

### int QDesktopWidget.numScreens (self)

### int QDesktopWidget.primaryScreen (self)

### QDesktopWidget.resizeEvent (self, QResizeEvent e)

Reimplemented from QWidget.resizeEvent().

### QWidget QDesktopWidget.screen (self, int screen = -1)

Returns a widget that represents the screen with index screen (a value of -1 means the default screen).

If the system uses a virtual desktop, the returned widget will have the geometry of the entire virtual desktop; i.e., bounding every screen.

See also primaryScreen, screenCount, and virtualDesktop.

### int QDesktopWidget.screenCount (self)

### QRect QDesktopWidget.screenGeometry (self, int screen = -1)

Returns the geometry of the screen with index screen. The default screen is used if screen is -1.

See also screenNumber().

### QRect QDesktopWidget.screenGeometry (self, QWidget widget)

This is an overloaded function.

Returns the geometry of the screen which contains widget.

### QRect QDesktopWidget.screenGeometry (self, QPoint point)

This is an overloaded function.

Returns the geometry of the screen which contains p.

### int QDesktopWidget.screenNumber (self, QWidget widget = None)

Returns the index of the screen that contains the largest part of widget, or -1 if the widget not on a screen.

See also primaryScreen.

### int QDesktopWidget.screenNumber (self, QPoint)

This is an overloaded function.

Returns the index of the screen that contains the point, or the screen which is the shortest distance from the point.

See also primaryScreen.

## Qt Signal Documentation

### void resized (int)

This is the default overload of this signal.

This signal is emitted when the size of screen changes.

### void screenCountChanged (int)

This is the default overload of this signal.

This signal is emitted when the number of screens changes to newCount.

This function was introduced in Qt 4.6.

See also screenCount.

### void workAreaResized (int)

This is the default overload of this signal.

This signal is emitted when the work area available on screen changes.