QX11Info Class | Qt X11 Extras 5.5

- Qt 5.5
- Qt X11 Extras
- C++ Classes
- QX11Info
- Qt 5.5.1 Reference Documentation

# QX11Info Class

Provides information about the X display configuration. More...

Header: | #include <QX11Info>
qmake: | QT += x11extras
Since: | Qt 5.1

- List of all members, including inherited members

## Static Public Members

int | appDpiX(int screen = -1)
int | appDpiY(int screen = -1)
unsigned long | appRootWindow(int screen = -1)
int | appScreen()
unsigned long | appTime()
unsigned long | appUserTime()
xcb_connection_t * | connection()
Display * | display()
unsigned long | getTimestamp()
bool | isPlatformX11()
QByteArray | nextStartupId()
void | setAppTime(unsigned long time)
void | setAppUserTime(unsigned long time)
void | setNextStartupId(const QByteArray & id)

## Detailed Description

Provides information about the X display configuration.

The class provides two APIs: a set of non-static functions that provide information about a specific widget or pixmap, and a set of static functions that provide the default information for the application.

Warning: This class is only available on X11. For querying per-screen information in a portable way, use QDesktopWidget.

## Member Function Documentation

### `[static]` int QX11Info::appDpiX(int screen = -1)

Returns the horizontal resolution of the given screen in terms of the number of dots per inch.

The screen argument is an X screen number. Be aware that if the user's system uses Xinerama (as opposed to traditional X11 multiscreen), there is only one X screen. Use QDesktopWidget to query for information about Xinerama screens.

See also appDpiY().

### `[static]` int QX11Info::appDpiY(int screen = -1)

Returns the vertical resolution of the given screen in terms of the number of dots per inch.

The screen argument is an X screen number. Be aware that if the user's system uses Xinerama (as opposed to traditional X11 multiscreen), there is only one X screen. Use QDesktopWidget to query for information about Xinerama screens.

See also appDpiX().

### `[static]` unsigned long QX11Info::appRootWindow(int screen = -1)

Returns a handle for the applications root window on the given screen.

The screen argument is an X screen number. Be aware that if the user's system uses Xinerama (as opposed to traditional X11 multiscreen), there is only one X screen. Use QDesktopWidget to query for information about Xinerama screens.

See also QApplication::desktop().

### `[static]` int QX11Info::appScreen()

Returns the number of the screen where the application is being displayed.

This method refers to screens in the original X11 meaning with a different DISPLAY environment variable per screen. This information is only useful if your application needs to know on which X screen it is running.

In a typical multi-head configuration, multiple physical monitors are combined in one X11 screen. This means this method returns the same number for each of the physical monitors. In such a setup you are interested in the monitor information as provided by the X11 RandR extension. This is available through QDesktopWidget and QScreen.

See also display().

### `[static]` unsigned long QX11Info::appTime()

Returns the X11 time.

See also setAppTime() and appUserTime().

### `[static]` unsigned long QX11Info::appUserTime()

Returns the X11 user time.

See also setAppUserTime() and appTime().

### `[static]` xcb_connection_t * QX11Info::connection()

Returns the default XCB connection for the application.

See also display().

### `[static]` Display * QX11Info::display()

Returns the default display for the application.

See also appScreen().

### `[static]` unsigned long QX11Info::getTimestamp()

Fetches the current X11 time stamp from the X Server.

This method creates a property notify event and blocks till it is received back from the X Server.

This function was introduced in Qt 5.2.

### `[static]` bool QX11Info::isPlatformX11()

Returns true if the application is currently running on X11.

This function was introduced in Qt 5.2.

### `[static]` QByteArray QX11Info::nextStartupId()

Returns the startup ID that will be used for the next window to be shown by this process.

After the next window is shown, the next startup ID will be empty.

http://standards.freedesktop.org/startup-notification-spec/startup-notification-latest.txt

This function was introduced in Qt 5.4.

See also setNextStartupId().

### `[static]` void QX11Info::setAppTime(unsigned long time)

Sets the X11 time to the value specified by time.

See also appTime() and setAppUserTime().

### `[static]` void QX11Info::setAppUserTime(unsigned long time)

Sets the X11 user time as specified by time.

See also appUserTime() and setAppTime().

### `[static]` void QX11Info::setNextStartupId(const QByteArray & id)

Sets the next startup ID to id.

This is the startup ID that will be used for the next window to be shown by this process.

The startup ID of the first window comes from the environment variable DESKTOP_STARTUP_ID. This method is useful for subsequent windows, when the request comes from another process (e.g. via DBus).

This function was introduced in Qt 5.4.

See also nextStartupId().