QDesktopWidget(3qt)QDesktopWidget(3qt)NAMEQDesktopWidget - Access to screen information on multi-head systems
SYNOPSIS
#include <qdesktopwidget.h>
Inherits QWidget.
Public Members
QDesktopWidget ()
~QDesktopWidget ()
bool isVirtualDesktop () const
int numScreens () const
int primaryScreen () const
int screenNumber ( QWidget * widget = 0 ) const
int screenNumber ( const QPoint & point ) const
QWidget * screen ( int screen = -1 )
const QRect & screenGeometry ( int screen = -1 ) const
const QRect & screenGeometry ( QWidget * widget ) const
const QRect & screenGeometry ( const QPoint & p ) const
const QRect & availableGeometry ( int screen = -1 ) const
const QRect & availableGeometry ( QWidget * widget ) const
const QRect & availableGeometry ( const QPoint & p ) const
Signals
void resized ( int screen )
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, which usually has the size of the bounding
rectangle of all the screens (see isVirtualDesktop()). For an
application, one of the available screens is the primary screen, i.e.
the screen where the main widget resides (see primaryScreen()). All
windows opened in the context of the application must 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.
The QDesktopWidget provides information about the geometry of the
available screens with screenGeometry(). The number of screens
available is returned by numScreens(). The screen number that a
particular point or widget is located in is returned by screenNumber().
Widgets provided by Qt use this class, for example, to place tooltips,
menus and dialog boxes according to the parent or application widget.
Applications can use this class to save window positions, or to place
child widgets on one screen.
<center>
[Image Omitted]
</center>
In the illustration above, Application One's primary screen is screen
0, and App Two's primary screen is screen 1.
See also Advanced Widgets and Environment Classes.
MEMBER FUNCTION DOCUMENTATIONQDesktopWidget::QDesktopWidget ()
Creates the desktop widget.
If the system supports a virtual desktop, this widget will have the
size of the virtual desktop; otherwise this widget will have the size
of the primary screen.
Instead of using QDesktopWidget directly, use QApplication::desktop().
QDesktopWidget::~QDesktopWidget ()
Destroy the object and free allocated resources.
const QRect & QDesktopWidget::availableGeometry ( int screen = -1 ) const
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
Menubar on Mac OS X, or the taskbar on Windows).
See also screenNumber() and screenGeometry().
const QRect & QDesktopWidget::availableGeometry ( QWidget * widget ) const
This is an overloaded member function, provided for convenience. It
behaves essentially like the above function.
Returns the available geometry of the screen which contains widget.
See also screenGeometry().
const QRect & QDesktopWidget::availableGeometry ( const QPoint & p ) const
This is an overloaded member function, provided for convenience. It
behaves essentially like the above function.
Returns the available geometry of the screen which contains p.
See also screenGeometry().
bool QDesktopWidget::isVirtualDesktop () const
Returns TRUE if the system manages the available screens in a virtual
desktop; otherwise returns FALSE.
For virtual desktops, screen() will always return the same widget. The
size of the virtual desktop is the size of this desktop widget.
int QDesktopWidget::numScreens () const
Returns the number of available screens.
See also primaryScreen().
int QDesktopWidget::primaryScreen () const
Returns the index of the primary screen.
See also numScreens().
void QDesktopWidget::resized ( int screen ) [signal]
This signal is emitted when the size of screen changes.
QWidget * QDesktopWidget::screen ( int screen = -1 )
Returns a widget that represents the screen with index screen. This
widget can be used to draw directly on the desktop, using an unclipped
painter like this:
QPainter paint( QApplication::desktop()->screen( 0 ), TRUE );
paint.draw...
...
paint.end();
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(), numScreens(), and isVirtualDesktop().
const QRect & QDesktopWidget::screenGeometry ( int screen = -1 ) const
Returns the geometry of the screen with index screen.
See also screenNumber().
const QRect & QDesktopWidget::screenGeometry ( QWidget * widget ) const
This is an overloaded member function, provided for convenience. It
behaves essentially like the above function.
Returns the geometry of the screen which contains widget.
const QRect & QDesktopWidget::screenGeometry ( const QPoint & p ) const
This is an overloaded member function, provided for convenience. It
behaves essentially like the above function.
Returns the geometry of the screen which contains p.
int QDesktopWidget::screenNumber ( QWidget * widget = 0 ) const
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 ( const QPoint & point ) const
This is an overloaded member function, provided for convenience. It
behaves essentially like the above function.
Returns the index of the screen that contains point, or -1 if no screen
contains the point.
See also primaryScreen().
SEE ALSO
http://doc.trolltech.com/qdesktopwidget.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
license file included in the distribution for a complete license
statement.
AUTHOR
Generated automatically from the source code.
BUGS
If you find a bug in Qt, please report it as described in
http://doc.trolltech.com/bughowto.html. Good bug reports help us to
help you. Thank you.
The definitive Qt documentation is provided in HTML format; it is
located at $QTDIR/doc/html and can be read using Qt Assistant or with a
web browser. This man page is provided as a convenience for those users
who prefer man pages, although this format is not officially supported
by Trolltech.
If you find errors in this manual page, please report them to qt-
bugs@trolltech.com. Please include the name of the manual page
(qdesktopwidget.3qt) and the Qt version (3.3.8).
Trolltech AS 2 February 2007 QDesktopWidget(3qt)
