GdkDisplay

GdkDisplay — Controls a set of monitors and their associated input devices

Properties

gboolean composited Read
gboolean input-shapes Read
gboolean rgba Read

Signals

void closed Run Last
void opened Run Last
void seat-added Run Last
void seat-removed Run Last
void setting-changed Run Last

Types and Values

Object Hierarchy

    GObject
    ╰── GdkDisplay

Includes

#include <gdk/gdk.h>

Description

GdkDisplay objects are the GDK representation of a workstation.

Their purpose are two-fold:

  • To manage and provide information about input devices (pointers, keyboards, etc)

  • To manage and provide information about output devices (monitors, projectors, etc)

Most of the input device handling has been factored out into separate GdkSeat objects. Every display has a one or more seats, which can be accessed with gdk_display_get_default_seat() and gdk_display_list_seats().

Output devices are represented by GdkMonitor objects, which can be accessed with gdk_display_get_monitor() and similar APIs.

Functions

gdk_display_open ()

GdkDisplay *
gdk_display_open (const gchar *display_name);

Opens a display.

Parameters

display_name

the name of the display to open

 

Returns

a GdkDisplay, or NULL if the display could not be opened.

[nullable][transfer none]


gdk_display_get_default ()

GdkDisplay *
gdk_display_get_default (void);

Gets the default GdkDisplay. This is a convenience function for: gdk_display_manager_get_default_display (gdk_display_manager_get()).

Returns

a GdkDisplay, or NULL if there is no default display.

[nullable][transfer none]


gdk_display_get_name ()

const gchar *
gdk_display_get_name (GdkDisplay *display);

Gets the name of the display.

Parameters

display

a GdkDisplay

 

Returns

a string representing the display name. This string is owned by GDK and should not be modified or freed.


gdk_display_device_is_grabbed ()

gboolean
gdk_display_device_is_grabbed (GdkDisplay *display,
                               GdkDevice *device);

Returns TRUE if there is an ongoing grab on device for display .

Parameters

display

a GdkDisplay

 

device

a GdkDevice

 

Returns

TRUE if there is a grab in effect for device .


gdk_display_beep ()

void
gdk_display_beep (GdkDisplay *display);

Emits a short beep on display

Parameters

display

a GdkDisplay

 

gdk_display_sync ()

void
gdk_display_sync (GdkDisplay *display);

Flushes any requests queued for the windowing system and waits until all requests have been handled. This is often used for making sure that the display is synchronized with the current state of the program. Calling gdk_display_sync() before gdk_error_trap_pop() makes sure that any errors generated from earlier requests are handled before the error trap is removed.

This is most useful for X11. On windowing systems where requests are handled synchronously, this function will do nothing.

Parameters

display

a GdkDisplay

 

gdk_display_flush ()

void
gdk_display_flush (GdkDisplay *display);

Flushes any requests queued for the windowing system; this happens automatically when the main loop blocks waiting for new events, but if your application is drawing without returning control to the main loop, you may need to call this function explicitly. A common case where this function needs to be called is when an application is executing drawing commands from a thread other than the thread where the main loop is running.

This is most useful for X11. On windowing systems where requests are handled synchronously, this function will do nothing.

Parameters

display

a GdkDisplay

 

gdk_display_close ()

void
gdk_display_close (GdkDisplay *display);

Closes the connection to the windowing system for the given display, and cleans up associated resources.

Parameters

display

a GdkDisplay

 

gdk_display_is_closed ()

gboolean
gdk_display_is_closed (GdkDisplay *display);

Finds out if the display has been closed.

Parameters

display

a GdkDisplay

 

Returns

TRUE if the display is closed.


gdk_display_is_rgba ()

gboolean
gdk_display_is_rgba (GdkDisplay *display);

Returns wether surfaces on this display are created with an alpha channel.

Even if a TRUE is returned, it is possible that the surface’s alpha channel won’t be honored when displaying the surface on the screen: in particular, for X an appropriate windowing manager and compositing manager must be running to provide appropriate display. Use gdk_display_is_composited() to check if that is the case.

For setting an overall opacity for a top-level surface, see gdk_surface_set_opacity().

On modern displays, this value is always TRUE.

Parameters

display

a GdkDisplay

 

Returns

TRUE if surfaces are created with an alpha channel or FALSE if the display does not support this functionality.


gdk_display_is_composited ()

gboolean
gdk_display_is_composited (GdkDisplay *display);

Returns whether surfaces can reasonably be expected to have their alpha channel drawn correctly on the screen. Check gdk_display_is_rgba() for wether the display supports an alpha channel.

On X11 this function returns whether a compositing manager is compositing on display .

On modern displays, this value is always TRUE.

Parameters

display

a GdkDisplay

 

Returns

Whether surfaces with RGBA visuals can reasonably be expected to have their alpha channels drawn correctly on the screen.


gdk_display_get_default_group ()

GdkSurface *
gdk_display_get_default_group (GdkDisplay *display);

Returns the default group leader surface for all toplevel surfaces on display . This surface is implicitly created by GDK. See gdk_surface_set_group().

Parameters

display

a GdkDisplay

 

Returns

The default group leader surface for display .

[transfer none]


gdk_display_supports_input_shapes ()

gboolean
gdk_display_supports_input_shapes (GdkDisplay *display);

Returns TRUE if gdk_surface_input_shape_combine_mask() can be used to modify the input shape of surfaces on display .

Parameters

display

a GdkDisplay

 

Returns

TRUE if surfaces with modified input shape are supported


gdk_display_get_app_launch_context ()

GdkAppLaunchContext *
gdk_display_get_app_launch_context (GdkDisplay *display);

Returns a GdkAppLaunchContext suitable for launching applications on the given display.

Parameters

display

a GdkDisplay

 

Returns

a new GdkAppLaunchContext for display . Free with g_object_unref() when done.

[transfer full]


gdk_display_notify_startup_complete ()

void
gdk_display_notify_startup_complete (GdkDisplay *display,
                                     const gchar *startup_id);

Indicates to the GUI environment that the application has finished loading, using a given identifier.

GTK+ will call this function automatically for GtkWindow with custom startup-notification identifier unless gtk_window_set_auto_startup_notification() is called to disable that feature.

Parameters

display

a GdkDisplay

 

startup_id

a startup-notification identifier, for which notification process should be completed

 

gdk_display_get_default_seat ()

GdkSeat *
gdk_display_get_default_seat (GdkDisplay *display);

Returns the default GdkSeat for this display.

Note that a display may not have a seat. In this case, this function will return NULL.

Parameters

display

a GdkDisplay

 

Returns

the default seat.

[transfer none][nullable]


gdk_display_list_seats ()

GList *
gdk_display_list_seats (GdkDisplay *display);

Returns the list of seats known to display .

Parameters

display

a GdkDisplay

 

Returns

the list of seats known to the GdkDisplay.

[transfer container][element-type GdkSeat]


gdk_display_get_monitors ()

GListModel *
gdk_display_get_monitors (GdkDisplay *self);

Gets the list of monitors associated with this display.

Subsequent calls to this function will always return the same list for the same display.

You can listen to the GListModel::items-changed signal on this list to monitor changes to the monitor of this display.

Parameters

self

a GdkDisplay

 

Returns

a GListModel of GdkMonitor.

[transfer none]


gdk_display_get_monitor_at_surface ()

GdkMonitor *
gdk_display_get_monitor_at_surface (GdkDisplay *display,
                                    GdkSurface *surface);

Gets the monitor in which the largest area of surface resides, or a monitor close to surface if it is outside of all monitors.

Parameters

display

a GdkDisplay

 

surface

a GdkSurface

 

Returns

the monitor with the largest overlap with surface .

[transfer none]


gdk_display_get_clipboard ()

GdkClipboard *
gdk_display_get_clipboard (GdkDisplay *display);

Gets the clipboard used for copy/paste operations.

Parameters

display

a GdkDisplay

 

Returns

the display's clipboard.

[transfer none]


gdk_display_get_primary_clipboard ()

GdkClipboard *
gdk_display_get_primary_clipboard (GdkDisplay *display);

Gets the clipboard used for the primary selection. On backends where the primary clipboard is not supported natively, GDK emulates this clipboard locally.

Parameters

display

a GdkDisplay

 

Returns

the primary clipboard.

[transfer none]


gdk_display_get_setting ()

gboolean
gdk_display_get_setting (GdkDisplay *display,
                         const char *name,
                         GValue *value);

Retrieves a desktop-wide setting such as double-click time for the display .

Parameters

display

a GdkDisplay

 

name

the name of the setting

 

value

location to store the value of the setting

 

Returns

TRUE if the setting existed and a value was stored in value , FALSE otherwise


gdk_display_get_startup_notification_id ()

const gchar *
gdk_display_get_startup_notification_id
                               (GdkDisplay *display);

Gets the startup notification ID for a Wayland display, or NULL if no ID has been defined.

Parameters

display

a GdkDisplay

 

Returns

the startup notification ID for display , or NULL


gdk_display_put_event ()

void
gdk_display_put_event (GdkDisplay *display,
                       GdkEvent *event);

Appends the given event onto the front of the event queue for display .

This function is only useful in very special situations and should not be used by applications.

Parameters

display

a GdkDisplay

 

event

a GdkEvent.

[transfer none]

gdk_display_map_keyval ()

gboolean
gdk_display_map_keyval (GdkDisplay *display,
                        guint keyval,
                        GdkKeymapKey **keys,
                        int *n_keys);

Obtains a list of keycode/group/level combinations that will generate keyval . Groups and levels are two kinds of keyboard mode; in general, the level determines whether the top or bottom symbol on a key is used, and the group determines whether the left or right symbol is used.

On US keyboards, the shift key changes the keyboard level, and there are no groups. A group switch key might convert a keyboard between Hebrew to English modes, for example.

GdkEventKey contains a group field that indicates the active keyboard group. The level is computed from the modifier mask.

The returned array should be freed with g_free().

Parameters

display

a GdkDisplay

 

keyval

a keyval, such as GDK_KEY_a, GDK_KEY_Up, GDK_KEY_Return, etc.

 

keys

return location for an array of GdkKeymapKey.

[out][array length=n_keys][transfer full]

n_keys

return location for number of elements in returned array

 

Returns

TRUE if keys were found and returned


gdk_display_map_keycode ()

gboolean
gdk_display_map_keycode (GdkDisplay *display,
                         guint keycode,
                         GdkKeymapKey **keys,
                         guint **keyvals,
                         int *n_entries);

Returns the keyvals bound to keycode . The Nth GdkKeymapKey in keys is bound to the Nth keyval in keyvals .

When a keycode is pressed by the user, the keyval from this list of entries is selected by considering the effective keyboard group and level.

Free the returned arrays with g_free().

Parameters

display

a GdkDisplay

 

keycode

a keycode

 

keys

return location for array of GdkKeymapKey, or NULL.

[out][array length=n_entries][transfer full][optional]

keyvals

return location for array of keyvals, or NULL.

[out][array length=n_entries][transfer full][optional]

n_entries

length of keys and keyvals

 

Returns

TRUE if there were any entries


gdk_display_translate_key ()

gboolean
gdk_display_translate_key (GdkDisplay *display,
                           guint keycode,
                           GdkModifierType state,
                           int group,
                           guint *keyval,
                           int *effective_group,
                           int *level,
                           GdkModifierType *consumed);

Translates the contents of a GdkEventKey (ie keycode , state , and group ) into a keyval, effective group, and level. Modifiers that affected the translation and are thus unavailable for application use are returned in consumed_modifiers .

The effective_group is the group that was actually used for the translation; some keys such as Enter are not affected by the active keyboard group. The level is derived from state .

consumed_modifiers gives modifiers that should be masked outfrom state when comparing this key press to a keyboard shortcut. For instance, on a US keyboard, the plus symbol is shifted, so when comparing a key press to a <Control>plus accelerator <Shift> should be masked out.

This function should rarely be needed, since GdkEventKey already contains the translated keyval. It is exported for the benefit of virtualized test environments.

Parameters

display

a GdkDisplay

 

keycode

a keycode

 

state

a modifier state

 

group

active keyboard group

 

keyval

return location for keyval, or NULL.

[out][optional]

effective_group

return location for effective group, or NULL.

[out][optional]

level

return location for level, or NULL.

[out][optional]

consumed

return location for modifiers that were used to determine the group or level, or NULL.

[out][optional]

Returns

TRUE if there was a keyval bound to keycode/state/group.

Types and Values

GdkDisplay

typedef struct _GdkDisplay GdkDisplay;

The GdkDisplay struct contains only private fields and should not be accessed directly.

Property Details

The “composited” property

  “composited”               gboolean

TRUE if the display properly composites the alpha channel. See gdk_display_is_composited() for details.

Owner: GdkDisplay

Flags: Read

Default value: TRUE


The “input-shapes” property

  “input-shapes”             gboolean

TRUE if the display supports input shapes. See gdk_display_supports_input_shapes() for details.

Owner: GdkDisplay

Flags: Read

Default value: TRUE


The “rgba” property

  “rgba”                     gboolean

TRUE if the display supports an alpha channel. See gdk_display_is_rgba() for details.

Owner: GdkDisplay

Flags: Read

Default value: TRUE

Signal Details

The “closed” signal

void
user_function (GdkDisplay *display,
               gboolean    is_error,
               gpointer    user_data)

The ::closed signal is emitted when the connection to the windowing system for display is closed.

Parameters

display

the object on which the signal is emitted

 

is_error

TRUE if the display was closed due to an error

 

user_data

user data set when the signal handler was connected.

 

Flags: Run Last


The “opened” signal

void
user_function (GdkDisplay *display,
               gpointer    user_data)

The ::opened signal is emitted when the connection to the windowing system for display is opened.

Parameters

display

the object on which the signal is emitted

 

user_data

user data set when the signal handler was connected.

 

Flags: Run Last


The “seat-added” signal

void
user_function (GdkDisplay *display,
               GdkSeat    *seat,
               gpointer    user_data)

The ::seat-added signal is emitted whenever a new seat is made known to the windowing system.

Parameters

display

the object on which the signal is emitted

 

seat

the seat that was just added

 

user_data

user data set when the signal handler was connected.

 

Flags: Run Last


The “seat-removed” signal

void
user_function (GdkDisplay *display,
               GdkSeat    *seat,
               gpointer    user_data)

The ::seat-removed signal is emitted whenever a seat is removed by the windowing system.

Parameters

display

the object on which the signal is emitted

 

seat

the seat that was just removed

 

user_data

user data set when the signal handler was connected.

 

Flags: Run Last


The “setting-changed” signal

void
user_function (GdkDisplay *display,
               gchar      *setting,
               gpointer    user_data)

The ::setting-changed signal is emitted whenever a setting changes its value.

Parameters

display

the object on which the signal is emitted

 

setting

the name of the setting that changed

 

user_data

user data set when the signal handler was connected.

 

Flags: Run Last