The QScreen class is used to query screen properties. More...

Inheritance diagram for QScreen:

Public Signals
void	availableGeometryChanged (const QRect &geometry)

void	geometryChanged (const QRect &geometry)

void	logicalDotsPerInchChanged (qreal dpi)

void	orientationChanged (Qt::ScreenOrientation orientation)

void	physicalDotsPerInchChanged (qreal dpi)

void	physicalSizeChanged (const QSizeF &size)

void	primaryOrientationChanged (Qt::ScreenOrientation orientation)

void	refreshRateChanged (qreal refreshRate)

void	virtualGeometryChanged (const QRect &rect)

Public Signals inherited from QObject
void	destroyed (QObject *obj=nullptr)

void	objectNameChanged (const QString &objectName)

Public Methods
	~QScreen ()

int	angleBetween (Qt::ScreenOrientation a, Qt::ScreenOrientation b) const

QRect	availableGeometry () const

QSize	availableSize () const

QRect	availableVirtualGeometry () const

QSize	availableVirtualSize () const

int	depth () const

qreal	devicePixelRatio () const

QRect	geometry () const

QPixmap	grabWindow (WId window, int x=0, int y=0, int width=-1, int height=-1)

QPlatformScreen *	handle () const

bool	isLandscape (Qt::ScreenOrientation orientation) const

bool	isPortrait (Qt::ScreenOrientation orientation) const

qreal	logicalDotsPerInch () const

qreal	logicalDotsPerInchX () const

qreal	logicalDotsPerInchY () const

QRect	mapBetween (Qt::ScreenOrientation a, Qt::ScreenOrientation b, const QRect &rect) const

QString	name () const

Qt::ScreenOrientation	nativeOrientation () const

Qt::ScreenOrientation	orientation () const

Qt::ScreenOrientations	orientationUpdateMask () const

qreal	physicalDotsPerInch () const

qreal	physicalDotsPerInchX () const

qreal	physicalDotsPerInchY () const

QSizeF	physicalSize () const

Qt::ScreenOrientation	primaryOrientation () const

qreal	refreshRate () const

void	setOrientationUpdateMask (Qt::ScreenOrientations mask)

QSize	size () const

QTransform	transformBetween (Qt::ScreenOrientation a, Qt::ScreenOrientation b, const QRect &target) const

QRect	virtualGeometry () const

QList< QScreen * >	virtualSiblings () const

QSize	virtualSize () const

Public Methods inherited from QObject
	QObject (QObject *parent=nullptr)

	~QObject ()

bool	blockSignals (bool block)

const QList< QObject * > &	children () const

bool	connect (const QObject *sender, const QString &signalMethod, const QString &location, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	connect (const QObject *sender, const QString &signalMethod, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	disconnect (const QObject *receiver, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod, const QString &location, const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod=QString (), const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QString >	dynamicPropertyNames () const

virtual bool	event (QEvent *event)

virtual bool	eventFilter (QObject watched, QEvent event)

template<typename T >
T	findChild (const QString &childName=QString ()) const

template<class T >
QList< T >	findChildren (const QRegularExpression &regExp, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

template<class T >
QList< T >	findChildren (const QString &childName=QString (), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

bool	inherits (const QString &className) const

void	installEventFilter (QObject *filterObj)

bool	isWidgetType () const

bool	isWindowType () const

void	killTimer (int id)

const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

QString	objectName () const

QObject *	parent () const

template<class T = QVariant>
T	property (const QString &name) const

void	removeEventFilter (QObject *obj)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const QString &name, const QVariant &value)

bool	signalsBlocked () const

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)

QThread *	thread () const

Properties
	availableGeometry
	Screen's available geometry in pixels. More...

	availableSize
	Screen's available size in pixels. More...

	availableVirtualGeometry
	Available geometry of the virtual desktop to which this screen belongs. More...

	availableVirtualSize
	Available size of the virtual desktop to which this screen belongs. More...

	depth
	Color depth of the screen. More...

	devicePixelRatio
	Screen's ratio between physical pixels and device-independent pixels. More...

	geometry
	Screen's geometry in pixels. More...

	logicalDotsPerInch
	Number of logical dots or pixels per inch. More...

	logicalDotsPerInchX
	Number of logical dots or pixels per inch in the horizontal direction. More...

	logicalDotsPerInchY
	Number of logical dots or pixels per inch in the vertical direction. More...

	name
	User presentable string representing the screen. More...

	nativeOrientation
	Native screen orientation. More...

	orientation
	Screen orientation. More...

	physicalDotsPerInch
	Number of physical dots or pixels per inch. More...

	physicalDotsPerInchX
	Number of physical dots or pixels per inch in the horizontal direction. More...

	physicalDotsPerInchY
	Number of physical dots or pixels per inch in the vertical direction. More...

	physicalSize
	Screen's physical size (in millimeters) More...

	primaryOrientation
	Primary screen orientation. More...

	refreshRate
	Approximate vertical refresh rate of the screen in Hz. More...

	size

	virtualGeometry
	the pixel geometry of the virtual desktop to which this screen belongs More...

	virtualSize
	Pixel size of the virtual desktop to which this screen belongs. More...

Properties inherited from QObject
	objectName

Friends
class	QPlatformIntegration

class	QPlatformScreen

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()

Static Public Methods inherited from QObject
static bool	connect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

static bool	connect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection, const QString &location=QString ())

static bool	connect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...), Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotLambda, Qt::ConnectionType type=Qt::AutoConnection)

static bool	disconnect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, std::nullptr_t, const QObject receiver, std::nullptr_t)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...))

template<class Sender , class SignalClass , class... SignalArgs, class Receiver >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, std::nullptr_t slotMethod=nullptr)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotMethod)

static QMetaObject &	staticMetaObject ()

static QString	tr (const char text, const char comment=nullptr, std::optional< int > numArg=std::optional< int >())

Protected Methods inherited from QObject
virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const QMetaMethod &signalMethod) const

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const QMetaMethod &signalMethod) const

bool	isSignalConnected (const QMetaMethod &signalMethod) const

int	receivers (const QString &signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Related Functions inherited from QObject
T	qobject_cast (QObject *object)

	QObjectList

Detailed Description

The QScreen class is used to query screen properties.

A note on logical vs physical dots per inch: physical DPI is based on the actual physical pixel sizes when available, and is useful for print preview and other cases where it's desirable to know the exact physical dimensions of screen displayed contents.

Logical dots per inch are used to convert font and user interface elements from point sizes to pixel sizes, and might be different from the physical dots per inch. The logical dots per inch are sometimes user-settable in the desktop environment's settings panel, to let the user globally control UI and font sizes in different applications.

Constructor & Destructor Documentation

QScreen::~QScreen ( )

Destroys the screen.

Method Documentation

int QScreen::angleBetween	(	Qt::ScreenOrientation	a,
		Qt::ScreenOrientation	b
	)		const

Computes the angle of rotation to get from rotation a to rotation b. The result will be 0, 90, 180, or 270. Qt::PrimaryOrientation is interpreted as the screen's primaryOrientation().

QRect QScreen::availableGeometry ( ) const

Returns the value of the property.

void QScreen::availableGeometryChanged ( const QRect & geometry )

signal

This signal is emitted when the value of the property changes. The specified geometry represents the updated value.

QSize QScreen::availableSize ( ) const

Returns the value of the property.

QRect QScreen::availableVirtualGeometry ( ) const

Returns the value of the property.

QSize QScreen::availableVirtualSize ( ) const

Returns the value of the property.

int QScreen::depth ( ) const

Returns the value of the property.

qreal QScreen::devicePixelRatio ( ) const

Returns the value of the property.

QRect QScreen::geometry ( ) const

Returns the value of the property.

void QScreen::geometryChanged ( const QRect & geometry )

signal

This signal is emitted when the value of the property changes. The specified geometry represents the updated value.

QPixmap QScreen::grabWindow	(	WId	window,
		int	x = `0`,
		int	y = `0`,
		int	width = `-1`,
		int	height = `-1`
	)

Creates and returns a pixmap constructed by grabbing the contents of the given window restricted by QRect(x, y, width, height).

The arguments (x, y) specify the offset in the window, whereas (width, height) specify the area to be copied. If width is negative, the function copies everything to the right border of the window. If height is negative, the function copies everything to the bottom of the window.

The window system identifier (WId) can be retrieved using the QWidget::winId() function. The rationale for using a window identifier and not a QWidget, is to enable grabbing of windows that are not part of the application, window system frames, and so on.

The grabWindow() function grabs pixels from the screen, not from the window, i.e. if there is another window partially or entirely over the one you grab, you get pixels from the overlying window, too. The mouse cursor is generally not grabbed.

On X11 that if the given window does not have the same depth as the root window, and another window partially or entirely obscures the one you grab, you will not get pixels from the overlying window. The contents of the obscured areas in the pixmap will be undefined and uninitialized.

On Windows Vista and above grabbing a layered window, which is created by setting the Qt::WA_TranslucentBackground attribute, will not work. Instead grabbing the desktop widget should work.

Warning: In general grabbing an area outside the screen is not safe. This depends on the underlying window system.

QPlatformScreen * QScreen::handle ( ) const

Get the platform screen handle.

bool QScreen::isLandscape ( Qt::ScreenOrientation orientation ) const

Returns true if orientation is either landscape or inverted landscape, otherwise returns false. Qt::PrimaryOrientation is interpreted as the screen's primaryOrientation().

bool QScreen::isPortrait ( Qt::ScreenOrientation orientation ) const

Returns true if orientation is either portrait or inverted portrait, otherwise returns false. Qt::PrimaryOrientation is interpreted as the screen's primaryOrientation().

qreal QScreen::logicalDotsPerInch ( ) const

Returns the value of the property.

void QScreen::logicalDotsPerInchChanged ( qreal dpi )

signal

This signal is emitted when the value of the property changes. The specified dpi represents the updated value.

qreal QScreen::logicalDotsPerInchX ( ) const

Returns the value of the property.

qreal QScreen::logicalDotsPerInchY ( ) const

Returns the value of the property.

QRect QScreen::mapBetween	(	Qt::ScreenOrientation	a,
		Qt::ScreenOrientation	b,
		const QRect &	rect
	)		const

Maps the rect between two screen orientations.

This will flip the x and y dimensions of the rectangle rect if the orientation a is Qt::PortraitOrientation or Qt::InvertedPortraitOrientation and orientation b is Qt::LandscapeOrientation or Qt::InvertedLandscapeOrientation, or vice versa.

Qt::PrimaryOrientation is interpreted as the screen's primaryOrientation().

QString QScreen::name ( ) const

Returns the value of the property.

Qt::ScreenOrientation QScreen::nativeOrientation ( ) const

Returns the value of the property.

Qt::ScreenOrientation QScreen::orientation ( ) const

Returns the value of the property.

void QScreen::orientationChanged ( Qt::ScreenOrientation orientation )

signal

This signal is emitted when the orientation of the screen changes with orientation as an argument.

See also: orientation()

Qt::ScreenOrientations QScreen::orientationUpdateMask ( ) const

Returns the currently set orientation update mask.

See also: setOrientationUpdateMask()

qreal QScreen::physicalDotsPerInch ( ) const

Returns the value of the property.

void QScreen::physicalDotsPerInchChanged ( qreal dpi )

signal

This signal is emitted when the value of the property changes. The specified dpi represents the updated value.

qreal QScreen::physicalDotsPerInchX ( ) const

Returns the value of the property.

qreal QScreen::physicalDotsPerInchY ( ) const

Returns the value of the property.

QSizeF QScreen::physicalSize ( ) const

Returns the value of the property.

void QScreen::physicalSizeChanged ( const QSizeF & size )

signal

This signal is emitted when the value of the property changes. The specified size represents the updated value.

Qt::ScreenOrientation QScreen::primaryOrientation ( ) const

Returns the value of the property.

void QScreen::primaryOrientationChanged ( Qt::ScreenOrientation orientation )

signal

This signal is emitted when the primary orientation of the screen changes with orientation as an argument.

See also: primaryOrientation()

qreal QScreen::refreshRate ( ) const

Returns the value of the property.

void QScreen::refreshRateChanged ( qreal refreshRate )

signal

This signal is emitted when the value of the property changes. The specified refreshRate represents the updated value.

void QScreen::setOrientationUpdateMask ( Qt::ScreenOrientations mask )

Sets the orientations that the application is interested in receiving updates for in conjunction with this screen.

As an example, to receive orientation() updates and thus have orientationChanged() signals being emitted for LandscapeOrientation and InvertedLandscapeOrientation, call setOrientationUpdateMask() with mask set to Qt::LandscapeOrientation | Qt::InvertedLandscapeOrientation.

The default of 0 means no orientationChanged() signals are emitted.

QSize QScreen::size ( ) const

Returns the value of the property.

QTransform QScreen::transformBetween	(	Qt::ScreenOrientation	a,
		Qt::ScreenOrientation	b,
		const QRect &	target
	)		const

Computes a transform that maps from the coordinate system defined by orientation a into the coordinate system defined by orientation b and target dimensions target.

As an example, the value for a is Qt::Landscape, the value for b is Qt::Portrait, and the value for target is QRect(0, 0, w, h). The resulting transform will place the point QPoint(0, 0) at QPoint(0, w), and QPoint(h, w) is mapped to QPoint(0, h). Thus, the landscape coordinate system QRect(0, 0, h, w) is mapped (with a 90 degree rotation) into the portrait coordinate system QRect(0, 0, w, h).

Qt::PrimaryOrientation is interpreted as the screen's primaryOrientation().

QRect QScreen::virtualGeometry ( ) const

Returns the value of the property.

void QScreen::virtualGeometryChanged ( const QRect & rect )

signal

This signal is emitted when the value of the property changes. The specified rect represents the updated value.

QList< QScreen * > QScreen::virtualSiblings ( ) const

Get the screen's virtual siblings.

The virtual siblings are the screen instances sharing the same virtual desktop. They share a common coordinate system, and windows can freely be moved or positioned across them without having to be recreated.

QSize QScreen::virtualSize ( ) const

Returns the value of the property.

Property Documentation

QScreen::availableGeometry

The available geometry is the geometry excluding window manager reserved areas such as task bars and system menus.

Properties	Class Methods
read	availableGeometry
notify	availableGeometryChanged

QScreen::availableSize

The available size is the size excluding window manager reserved areas such as task bars and system menus.

Properties	Class Methods
read	availableSize
notify	availableGeometryChanged

QScreen::availableVirtualGeometry

Returns the available geometry of the virtual desktop corresponding to this screen. This is the union of the virtual siblings' individual available geometries.

See also: availableGeometry(), virtualSiblings()

Properties	Class Methods
read	availableVirtualGeometry
notify	virtualGeometryChanged

QScreen::availableVirtualSize

Returns the available pixel size of the virtual desktop corresponding to this screen. This is the combined size of the virtual siblings' individual available geometries.

See also: availableSize(), virtualSiblings()

Properties	Class Methods
read	availableVirtualSize
notify	virtualGeometryChanged

QScreen::depth

Color depth of the screen.

Properties	Class Methods
read	depth
constant	true

QScreen::devicePixelRatio

Returns the ratio between physical pixels and device-independent pixels for the screen. Common values are 1.0 on normal displays and 2.0 on "retina" displays. Higher values are also possible.

See also: QWindow::devicePixelRatio(), QApplication::devicePixelRatio()

Properties	Class Methods
read	devicePixelRatio
notify	physicalDotsPerInchChanged

QScreen::geometry

As an example this might return QRect(0, 0, 1280, 1024), or in a virtual desktop setting QRect(1280, 0, 1280, 1024).

Properties	Class Methods
read	geometry
notify	geometryChanged

QScreen::logicalDotsPerInch

This value can be used to convert font point sizes to pixel sizes. This is a convenience property that's simply the average of the logicalDotsPerInchX and logicalDotsPerInchY properties.

See also: logicalDotsPerInchX(), logicalDotsPerInchY()

Properties	Class Methods
read	logicalDotsPerInch
notify	logicalDotsPerInchChanged

QScreen::logicalDotsPerInchX

This value is used to convert font point sizes to pixel sizes.

See also: logicalDotsPerInchY()

Properties	Class Methods
read	logicalDotsPerInchX
notify	logicalDotsPerInchChanged

QScreen::logicalDotsPerInchY

This value is used to convert font point sizes to pixel sizes.

See also: logicalDotsPerInchX()

Properties	Class Methods
read	logicalDotsPerInchY
notify	logicalDotsPerInchChanged

QScreen::name

For example on X11 these correspond to the XRandr screen names, typically "VGA1", "HDMI1", etc.

Properties	Class Methods
read	name
constant	true

QScreen::nativeOrientation

The native orientation of the screen is the orientation where the logo sticker of the device appears the right way up, or Qt::Primary Orientation if the platform does not support this functionality.

The native orientation is a property of the hardware, and does not change.

Properties	Class Methods
read	nativeOrientation

QScreen::orientation

The screen orientation represents the physical orientation of the display. For example, the screen orientation of a mobile device will change based on how it is being held. A change to the orientation might or might not trigger a change to the primary orientation of the screen.

Changes to this property will be filtered by orientationUpdateMask(), so in order to receive orientation updates the application must first call setOrientationUpdateMask() with a mask of the orientations it wants to receive.

Qt::PrimaryOrientation is never returned.

See also: primaryOrientation()

Properties	Class Methods
read	orientation
notify	orientationChanged

QScreen::physicalDotsPerInch

This value represents the pixel density on the screen's display. Depending on what information the underlying system provides the value might not be entirely accurate.

This is a convenience property that is the average of the physicalDotsPerInchX and physicalDotsPerInchY properties.

See also: physicalDotsPerInchX(), physicalDotsPerInchY()

Properties	Class Methods
read	physicalDotsPerInch
notify	physicalDotsPerInchChanged

QScreen::physicalDotsPerInchX

This value represents the actual horizontal pixel density on the screen's display. Depending on what information the underlying system provides the value might not be entirely accurate.

See also: physicalDotsPerInchY()

Properties	Class Methods
read	physicalDotsPerInchX
notify	physicalDotsPerInchChanged

QScreen::physicalDotsPerInchY

This value represents the actual vertical pixel density on the screen's display. Depending on what information the underlying system provides the value might not be entirely accurate.

See also: physicalDotsPerInchX()

Properties	Class Methods
read	physicalDotsPerInchY
notify	physicalDotsPerInchChanged

QScreen::physicalSize

The physical size represents the actual physical dimensions of the screen's display. Depending on what information the underlying system provides the value might not be entirely accurate.

Properties	Class Methods
read	physicalSize
notify	physicalSizeChanged

QScreen::primaryOrientation

The primary screen orientation is Qt::LandscapeOrientation if the screen geometry's width is greater than or equal to its height, or Qt::PortraitOrientation otherwise. This property might change when the screen orientation was changed for example when the display is rotated.

The behavior is however platform dependent and can often be specified in an application manifest file.

Properties	Class Methods
read	primaryOrientation
notify	primaryOrientationChanged

QScreen::refreshRate

Approximate vertical refresh rate of the screen in Hz.

Properties	Class Methods
read	refreshRate
notify	refreshRateChanged

QScreen::size

This property holds the pixel resolution of the screen.

Properties	Class Methods
read	size
notify	geometryChanged

QScreen::virtualGeometry

Returns the pixel geometry of the virtual desktop corresponding to this screen. This is the union of the virtual siblings' individual geometries.

See also: virtualSiblings()

Properties	Class Methods
read	virtualGeometry
notify	virtualGeometryChanged

QScreen::virtualSize

Returns the pixel size of the virtual desktop corresponding to this screen. This is the combined size of the virtual siblings' individual geometries.

See also: virtualSiblings()

Properties	Class Methods
read	virtualSize
notify	virtualGeometryChanged

Public Signals

Public Methods

Properties

Friends

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Method Documentation

Property Documentation