QScreen Class
The QScreen class is used to query screen properties. More...
| Header: | #include <QScreen> |
| qmake: | QT += gui |
| Since: | Qt 5.0 |
| Inherits: | QObject |
This class was introduced in Qt 5.0.
Properties
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Public Functions
| QRect | availableGeometry() const |
| QSize | availableSize() const |
| QRect | availableVirtualGeometry() const |
| QSize | availableVirtualSize() const |
| int | depth() const |
| qreal | devicePixelRatio() const |
| QRect | geometry() const |
| qreal | logicalDotsPerInch() const |
| qreal | logicalDotsPerInchX() const |
| qreal | logicalDotsPerInchY() const |
| QString | manufacturer() const |
| QString | model() const |
| QString | name() const |
| Qt::ScreenOrientation | nativeOrientation() const |
| Qt::ScreenOrientation | orientation() const |
| qreal | physicalDotsPerInch() const |
| qreal | physicalDotsPerInchX() const |
| qreal | physicalDotsPerInchY() const |
| QSizeF | physicalSize() const |
| Qt::ScreenOrientation | primaryOrientation() const |
| qreal | refreshRate() const |
| QString | serialNumber() const |
| QSize | size() const |
| QRect | virtualGeometry() const |
| QSize | virtualSize() const |
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) |
Detailed Description
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.
Property Documentation
availableGeometry : const QRect
This property holds the screen's available geometry in pixels
The available geometry is the geometry excluding window manager reserved areas such as task bars and system menus.
Note, on X11 this will return the true available geometry only on systems with one monitor and if window manager has set _NET_WORKAREA atom. In all other cases this is equal to geometry(). This is a limitation in X11 window manager specification.
Access functions:
| QRect | availableGeometry() const |
Notifier signal:
| void | availableGeometryChanged(const QRect &geometry) |
availableSize : const QSize
This property holds the screen's available size in pixels
The available size is the size excluding window manager reserved areas such as task bars and system menus.
Access functions:
| QSize | availableSize() const |
Notifier signal:
| void | availableGeometryChanged(const QRect &geometry) |
availableVirtualGeometry : const QRect
This property holds the available geometry of the virtual desktop to which this screen belongs
Returns the available geometry of the virtual desktop corresponding to this screen.
This is the union of the virtual siblings' individual available geometries.
Access functions:
| QRect | availableVirtualGeometry() const |
Notifier signal:
| void | virtualGeometryChanged(const QRect &rect) |
See also availableGeometry() and virtualSiblings().
availableVirtualSize : const QSize
This property holds the available size of the virtual desktop to which this screen belongs
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.
Access functions:
| QSize | availableVirtualSize() const |
Notifier signal:
| void | virtualGeometryChanged(const QRect &rect) |
See also availableSize() and virtualSiblings().
depth : const int
This property holds the color depth of the screen
Access functions:
| int | depth() const |
devicePixelRatio : const qreal
This property holds the screen's ratio between physical pixels and device-independent pixels
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.
This property was introduced in Qt 5.5.
Access functions:
| qreal | devicePixelRatio() const |
Notifier signal:
| void | physicalDotsPerInchChanged(qreal dpi) |
See also QWindow::devicePixelRatio() and QGuiApplication::devicePixelRatio().
geometry : const QRect
This property holds the screen's geometry in pixels
As an example this might return QRect(0, 0, 1280, 1024), or in a virtual desktop setting QRect(1280, 0, 1280, 1024).
Access functions:
| QRect | geometry() const |
Notifier signal:
| void | geometryChanged(const QRect &geometry) |
logicalDotsPerInch : const qreal
This property holds the number of logical dots or pixels per inch
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.
Access functions:
| qreal | logicalDotsPerInch() const |
Notifier signal:
| void | logicalDotsPerInchChanged(qreal dpi) |
See also logicalDotsPerInchX() and logicalDotsPerInchY().
logicalDotsPerInchX : const qreal
This property holds the number of logical dots or pixels per inch in the horizontal direction
This value is used to convert font point sizes to pixel sizes.
Access functions:
| qreal | logicalDotsPerInchX() const |
Notifier signal:
| void | logicalDotsPerInchChanged(qreal dpi) |
See also logicalDotsPerInchY().
logicalDotsPerInchY : const qreal
This property holds the number of logical dots or pixels per inch in the vertical direction
This value is used to convert font point sizes to pixel sizes.
Access functions:
| qreal | logicalDotsPerInchY() const |
Notifier signal:
| void | logicalDotsPerInchChanged(qreal dpi) |
See also logicalDotsPerInchX().
manufacturer : const QString
This property holds the manufacturer of the screen
This property was introduced in Qt 5.9.
Access functions:
| QString | manufacturer() const |
model : const QString
This property holds the model of the screen
This property was introduced in Qt 5.9.
Access functions:
| QString | model() const |
name : const QString
This property holds a user presentable string representing the screen
For example, on X11 these correspond to the XRandr screen names, typically "VGA1", "HDMI1", etc.
Access functions:
| QString | name() const |
nativeOrientation : const Qt::ScreenOrientation
This property holds the native screen orientation
The native orientation of the screen is the orientation where the logo sticker of the device appears the right way up, or Qt::PrimaryOrientation if the platform does not support this functionality.
The native orientation is a property of the hardware, and does not change.
This property was introduced in Qt 5.2.
Access functions:
| Qt::ScreenOrientation | nativeOrientation() const |
orientation : const Qt::ScreenOrientation
This property holds the screen 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.
Access functions:
| Qt::ScreenOrientation | orientation() const |
Notifier signal:
| void | orientationChanged(Qt::ScreenOrientation orientation) |
See also primaryOrientation().
physicalDotsPerInch : const qreal
This property holds the number of physical dots or pixels per inch
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's simply the average of the physicalDotsPerInchX and physicalDotsPerInchY properties.
Access functions:
| qreal | physicalDotsPerInch() const |
Notifier signal:
| void | physicalDotsPerInchChanged(qreal dpi) |
See also physicalDotsPerInchX() and physicalDotsPerInchY().
physicalDotsPerInchX : const qreal
This property holds the number of physical dots or pixels per inch in the horizontal direction
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.
Access functions:
| qreal | physicalDotsPerInchX() const |
Notifier signal:
| void | physicalDotsPerInchChanged(qreal dpi) |
See also physicalDotsPerInchY().
physicalDotsPerInchY : const qreal
This property holds the number of physical dots or pixels per inch in the vertical direction
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.
Access functions:
| qreal | physicalDotsPerInchY() const |
Notifier signal:
| void | physicalDotsPerInchChanged(qreal dpi) |
See also physicalDotsPerInchX().
physicalSize : const QSizeF
This property holds the screen's physical size (in millimeters)
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.
Access functions:
| QSizeF | physicalSize() const |
Notifier signal:
| void | physicalSizeChanged(const QSizeF &size) |
primaryOrientation : const Qt::ScreenOrientation
This property holds the primary screen orientation
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 (i.e. when the display is rotated). The behavior is however platform dependent and can often be specified in an application manifest file.
Access functions:
| Qt::ScreenOrientation | primaryOrientation() const |
Notifier signal:
| void | primaryOrientationChanged(Qt::ScreenOrientation orientation) |
refreshRate : const qreal
This property holds the approximate vertical refresh rate of the screen in Hz
Access functions:
| qreal | refreshRate() const |
Notifier signal:
| void | refreshRateChanged(qreal refreshRate) |
serialNumber : const QString
This property holds the serial number of the screen
This property was introduced in Qt 5.9.
Access functions:
| QString | serialNumber() const |
size : const QSize
This property holds the pixel resolution of the screen
Access functions:
| QSize | size() const |
Notifier signal:
| void | geometryChanged(const QRect &geometry) |
virtualGeometry : const QRect
This property holds the pixel geometry of the virtual desktop to which this screen belongs
Returns the pixel geometry of the virtual desktop corresponding to this screen.
This is the union of the virtual siblings' individual geometries.
Access functions:
| QRect | virtualGeometry() const |
Notifier signal:
| void | virtualGeometryChanged(const QRect &rect) |
See also virtualSiblings().
virtualSize : const QSize
This property holds the pixel size of the virtual desktop to which this screen belongs
Returns the pixel size of the virtual desktop corresponding to this screen.
This is the combined size of the virtual siblings' individual geometries.
Access functions:
| QSize | virtualSize() const |
Notifier signal:
| void | virtualGeometryChanged(const QRect &rect) |
See also virtualSiblings().