GI.Gdk.Objects.DisplayManager

A singleton object that offers notification when displays appear or disappear.

You can use [funcgdk.DisplayManager.get] to obtain the GdkDisplayManager singleton, but that should be rarely necessary. Typically, initializing GTK opens a display that you can work with without ever accessing the GdkDisplayManager.

The GDK library can be built with support for multiple backends. The GdkDisplayManager object determines which backend is used at runtime.

In the rare case that you need to influence which of the backends is being used, you can use setAllowedBackends. Note that you need to call this function before initializing GTK.

Backend-specific code

When writing backend-specific code that is supposed to work with multiple GDK backends, you have to consider both compile time and runtime. At compile time, use the GDK_WINDOWING_X11, GDK_WINDOWING_WIN32 macros, etc. to find out which backends are present in the GDK library you are building your application against. At runtime, use type-check macros like GDK_IS_X11_DISPLAY() to find out which backend is in use:

c code

#ifdef GDK_WINDOWING_X11
  if (GDK_IS_X11_DISPLAY (display))
    {
      // make X11-specific calls here
    }
  else
#endif
#ifdef GDK_WINDOWING_MACOS
  if (GDK_IS_MACOS_DISPLAY (display))
    {
      // make Quartz-specific calls here
    }
  else
#endif
  g_error ("Unsupported GDK backend");

Exported types

newtype DisplayManager

Memory-managed wrapper type.

Constructors

DisplayManager (ManagedPtr DisplayManager)

Instances

Eq DisplayManager

Defined in GI.Gdk.Objects.DisplayManager

Methods

(==) :: DisplayManager -> DisplayManager -> Bool

(/=) :: DisplayManager -> DisplayManager -> Bool

GObject DisplayManager

Defined in GI.Gdk.Objects.DisplayManager

ManagedPtrNewtype DisplayManager

Defined in GI.Gdk.Objects.DisplayManager

Methods

toManagedPtr :: DisplayManager -> ManagedPtr DisplayManager

TypedObject DisplayManager

Defined in GI.Gdk.Objects.DisplayManager

Methods

glibType :: IO GType

HasParentTypes DisplayManager

Defined in GI.Gdk.Objects.DisplayManager

IsGValue (Maybe DisplayManager)

Convert DisplayManager to and from GValue. See toGValue and fromGValue.

Defined in GI.Gdk.Objects.DisplayManager

Methods

gvalueGType_ :: IO GType

gvalueSet_ :: Ptr GValue -> Maybe DisplayManager -> IO ()

gvalueGet_ :: Ptr GValue -> IO (Maybe DisplayManager)

type ParentTypes DisplayManager

Defined in GI.Gdk.Objects.DisplayManager

type ParentTypes DisplayManager = '[Object]

class (GObject o, IsDescendantOf DisplayManager o) => IsDisplayManager o

Type class for types which can be safely cast to DisplayManager, for instance with toDisplayManager.

Instances

(GObject o, IsDescendantOf DisplayManager o) => IsDisplayManager o

Defined in GI.Gdk.Objects.DisplayManager

toDisplayManager :: (MonadIO m, IsDisplayManager o) => o -> m DisplayManager

Cast to DisplayManager, for types for which this is known to be safe. For general casts, use castTo.

Methods

Click to display all available methods, including inherited ones

Methods

bindProperty, bindPropertyFull, forceFloating, freezeNotify, getv, isFloating, listDisplays, notify, notifyByPspec, openDisplay, ref, refSink, runDispose, stealData, stealQdata, thawNotify, unref, watchClosure.

Getters

getData, getDefaultDisplay, getProperty, getQdata.

Setters

setData, setDataFull, setDefaultDisplay, setProperty.

get

displayManagerGet

Arguments

:: (HasCallStack, MonadIO m)

=> m DisplayManager

Returns: The global GdkDisplayManager singleton

Gets the singleton GdkDisplayManager object.

When called for the first time, this function consults the GDK_BACKEND environment variable to find out which of the supported GDK backends to use (in case GDK has been compiled with multiple backends).

Applications can use [funcsetAllowedBackends] to limit what backends will be used.

getDefaultDisplay

displayManagerGetDefaultDisplay

Arguments

:: (HasCallStack, MonadIO m, IsDisplayManager a)

=> a

manager: a GdkDisplayManager

-> m (Maybe Display)

Returns: a GdkDisplay

Gets the default GdkDisplay.

listDisplays

displayManagerListDisplays

Arguments

:: (HasCallStack, MonadIO m, IsDisplayManager a)

=> a

manager: a GdkDisplayManager

-> m [Display]

Returns: a newly allocated GSList of GdkDisplay objects

List all currently open displays.

openDisplay

displayManagerOpenDisplay

Arguments

:: (HasCallStack, MonadIO m, IsDisplayManager a)

=> a

manager: a GdkDisplayManager

-> Text

name: the name of the display to open

-> m (Maybe Display)

Returns: a GdkDisplay, or Nothing if the display could not be opened

Opens a display.

setDefaultDisplay

displayManagerSetDefaultDisplay

Arguments

:: (HasCallStack, MonadIO m, IsDisplayManager a, IsDisplay b)

=> a

manager: a GdkDisplayManager

-> b

display: a GdkDisplay

-> m ()

Sets display as the default display.

Properties

defaultDisplay

The default display.

constructDisplayManagerDefaultDisplay :: (IsDisplayManager o, MonadIO m, IsDisplay a) => a -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “default-display” property. This is rarely needed directly, but it is used by new.

getDisplayManagerDefaultDisplay :: (MonadIO m, IsDisplayManager o) => o -> m (Maybe Display)

Get the value of the “default-display” property. When overloading is enabled, this is equivalent to

get displayManager #defaultDisplay

setDisplayManagerDefaultDisplay :: (MonadIO m, IsDisplayManager o, IsDisplay a) => o -> a -> m ()

Set the value of the “default-display” property. When overloading is enabled, this is equivalent to

set displayManager [ #defaultDisplay := value ]

Signals

displayOpened

type DisplayManagerDisplayOpenedCallback

Arguments

 = Display

display: the opened display

-> IO ()

Emitted when a display is opened.

afterDisplayManagerDisplayOpened :: (IsDisplayManager a, MonadIO m) => a -> ((?self :: a) => DisplayManagerDisplayOpenedCallback) -> m SignalHandlerId

Connect a signal handler for the displayOpened signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after displayManager #displayOpened callback

By default the object invoking the signal is not passed to the callback. If you need to access it, you can use the implit ?self parameter. Note that this requires activating the ImplicitParams GHC extension.

onDisplayManagerDisplayOpened :: (IsDisplayManager a, MonadIO m) => a -> ((?self :: a) => DisplayManagerDisplayOpenedCallback) -> m SignalHandlerId

Connect a signal handler for the displayOpened signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on displayManager #displayOpened callback