GdkDisplay: GDK 2 Reference Manual

## GdkDisplay GdkDisplay |

## Functions

GdkDisplay * | gdk_display_open ()
GdkDisplay * | gdk_display_get_default ()
const gchar * | gdk_display_get_name ()
gint | gdk_display_get_n_screens ()
GdkScreen * | gdk_display_get_screen ()
GdkScreen * | gdk_display_get_default_screen ()
void | gdk_display_pointer_ungrab ()
void | gdk_display_keyboard_ungrab ()
gboolean | gdk_display_pointer_is_grabbed ()
void | gdk_display_beep ()
void | gdk_display_sync ()
void | gdk_display_flush ()
void | gdk_display_close ()
gboolean | gdk_display_is_closed ()
GList * | gdk_display_list_devices ()
GdkEvent * | gdk_display_get_event ()
GdkEvent * | gdk_display_peek_event ()
void | gdk_display_put_event ()
void | gdk_display_add_client_message_filter ()
void | gdk_display_set_double_click_time ()
void | gdk_display_set_double_click_distance ()
void | gdk_display_get_pointer ()
GdkWindow * | gdk_display_get_window_at_pointer ()
GdkDisplayPointerHooks * | gdk_display_set_pointer_hooks ()
void | gdk_display_warp_pointer ()
gboolean | gdk_display_supports_cursor_color ()
gboolean | gdk_display_supports_cursor_alpha ()
guint | gdk_display_get_default_cursor_size ()
void | gdk_display_get_maximal_cursor_size ()
GdkWindow * | gdk_display_get_default_group ()
gboolean | gdk_display_supports_selection_notification ()
gboolean | gdk_display_request_selection_notification ()
gboolean | gdk_display_supports_clipboard_persistence ()
void | gdk_display_store_clipboard ()
gboolean | gdk_display_supports_shapes ()
gboolean | gdk_display_supports_input_shapes ()
gboolean | gdk_display_supports_composite ()

## Signals

void | closed | Run Last

## Types and Values

| GdkDisplay
struct | GdkDisplayPointerHooks

## Object Hierarchy

        GObject
        ╰── GdkDisplay

## Includes

    #include <gdk/gdk.h>

## Description

## 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. |

Since: 2.2

### 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.

[transfer none]

Since: 2.2

### 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.

Since: 2.2

### gdk_display_get_n_screens ()

    gint
    gdk_display_get_n_screens (GdkDisplay *display);

Gets the number of screen managed by the `display` .

#### Parameters

display | a GdkDisplay |

#### Returns

number of screens.

Since: 2.2

### gdk_display_get_screen ()

    GdkScreen *
    gdk_display_get_screen (GdkDisplay *display,
                            gint screen_num);

Returns a screen object for one of the screens of the display.

#### Parameters

display | a GdkDisplay |
screen_num | the screen number |

#### Returns

the GdkScreen object

Since: 2.2

### gdk_display_get_default_screen ()

    GdkScreen *
    gdk_display_get_default_screen (GdkDisplay *display);

Get the default GdkScreen for `display` .

#### Parameters

display | a GdkDisplay |

#### Returns

the default GdkScreen object for `display`

Since: 2.2

### gdk_display_pointer_ungrab ()

    void
    gdk_display_pointer_ungrab (GdkDisplay *display,
                                guint32 time_);

Release any pointer grab.

#### Parameters

display | a GdkDisplay. |
time_ | a timestap (e.g. `GDK_CURRENT_TIME`). |

Since: 2.2

### gdk_display_keyboard_ungrab ()

    void
    gdk_display_keyboard_ungrab (GdkDisplay *display,
                                 guint32 time_);

Release any keyboard grab

#### Parameters

display | a GdkDisplay. |
time_ | a timestap (e.g GDK_CURRENT_TIME). |

Since: 2.2

### gdk_display_pointer_is_grabbed ()

    gboolean
    gdk_display_pointer_is_grabbed (GdkDisplay *display);

Test if the pointer is grabbed.

#### Parameters

display | a GdkDisplay |

#### Returns

`TRUE` if an active X pointer grab is in effect

Since: 2.2

### gdk_display_beep ()

    void
    gdk_display_beep (GdkDisplay *display);

Emits a short beep on `display`

#### Parameters

display | a GdkDisplay |

Since: 2.2

### 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 |

Since: 2.2

### 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 explicitely. 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 |

Since: 2.4

### 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 |

Since: 2.2

### 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.

Since: 2.22

### gdk_display_list_devices ()

    GList *
    gdk_display_list_devices (GdkDisplay *display);

Returns the list of available input devices attached to `display` . The list is statically allocated and should not be freed.

#### Parameters

display | a GdkDisplay |

#### Returns

a list of GdkDevice

Since: 2.2

### gdk_display_get_event ()

    GdkEvent *
    gdk_display_get_event (GdkDisplay *display);

Gets the next GdkEvent to be processed for `display` , fetching events from the windowing system if necessary.

#### Parameters

display | a GdkDisplay |

#### Returns

the next GdkEvent to be processed, or `NULL` if no events are pending. The returned GdkEvent should be freed with `gdk_event_free()`.

Since: 2.2

### gdk_display_peek_event ()

    GdkEvent *
    gdk_display_peek_event (GdkDisplay *display);

Gets a copy of the first GdkEvent in the `display` 's event queue, without removing the event from the queue. (Note that this function will not get more events from the windowing system. It only checks the events that have already been moved to the GDK event queue.)

#### Parameters

display | a GdkDisplay |

#### Returns

a copy of the first GdkEvent on the event queue, or `NULL` if no events are in the queue. The returned GdkEvent should be freed with `gdk_event_free()`.

Since: 2.2

### gdk_display_put_event ()

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

Appends a copy of the given event onto the front of the event queue for `display` .

#### Parameters

display | a GdkDisplay |
event | a GdkEvent. |

Since: 2.2

### gdk_display_add_client_message_filter ()

    void
    gdk_display_add_client_message_filter (GdkDisplay *display,
                                           GdkAtom message_type,
                                           GdkFilterFunc func,
                                           gpointer data);

Adds a filter to be called when X ClientMessage events are received. See `gdk_window_add_filter()` if you are interested in filtering other types of events.

#### Parameters

display | a GdkDisplay for which this message filter applies |
message_type | the type of ClientMessage events to receive. This will be checked against the `message_type` field of the XClientMessage event struct. |
func | the function to call to process the event. |
data | user data to pass to `func` . |

Since: 2.2

### gdk_display_set_double_click_time ()

    void
    gdk_display_set_double_click_time (GdkDisplay *display,
                                       guint msec);

Sets the double click time (two clicks within this time interval count as a double click and result in a GDK_2BUTTON_PRESS event). Applications should not set this, it is a global user-configured setting.

#### Parameters

display | a GdkDisplay |
msec | double click time in milliseconds (thousandths of a second) |

Since: 2.2

### gdk_display_set_double_click_distance ()

    void
    gdk_display_set_double_click_distance (GdkDisplay *display,
                                           guint distance);

Sets the double click distance (two clicks within this distance count as a double click and result in a GDK_2BUTTON_PRESS event). See also `gdk_display_set_double_click_time()`. Applications should not set this, it is a global user-configured setting.

#### Parameters

display | a GdkDisplay |
distance | distance in pixels |

Since: 2.4

### gdk_display_get_pointer ()

    void
    gdk_display_get_pointer (GdkDisplay *display,
                             GdkScreen **screen,
                             gint *x,
                             gint *y,
                             GdkModifierType *mask);

Gets the current location of the pointer and the current modifier mask for a given display.

#### Parameters

display | a GdkDisplay |
screen | location to store the screen that the cursor is on, or `NULL`. | [out][allow-none]
x | location to store root window X coordinate of pointer, or `NULL`. | [out][allow-none]
y | location to store root window Y coordinate of pointer, or `NULL`. | [out][allow-none]
mask | location to store current modifier mask, or `NULL`. | [out][allow-none]

Since: 2.2

### gdk_display_get_window_at_pointer ()

    GdkWindow *
    gdk_display_get_window_at_pointer (GdkDisplay *display,
                                       gint *win_x,
                                       gint *win_y);

Obtains the window underneath the mouse pointer, returning the location of the pointer in that window in `win_x` , `win_y` for `screen` . Returns `NULL` if the window under the mouse pointer is not known to GDK (for example, belongs to another application).

#### Parameters

display | a GdkDisplay |
win_x | return location for x coordinate of the pointer location relative to the window origin, or `NULL`. | [out][allow-none]
win_y | return location for y coordinate of the pointer location relative & to the window origin, or `NULL`. | [out][allow-none]

#### Returns

the window under the mouse pointer, or `NULL`.

[transfer none]

Since: 2.2

### gdk_display_set_pointer_hooks ()

    GdkDisplayPointerHooks *
    gdk_display_set_pointer_hooks (GdkDisplay *display,
                                   const GdkDisplayPointerHooks *new_hooks);

`gdk_display_set_pointer_hooks` has been deprecated since version 2.24 and should not be used in newly-written code.

This function will go away in GTK 3 for lack of use cases.

This function allows for hooking into the operation of getting the current location of the pointer on a particular display. This is only useful for such low-level tools as an event recorder. Applications should never have any reason to use this facility.

#### Parameters

display | a GdkDisplay |
new_hooks | a table of pointers to functions for getting quantities related to the current pointer position, or `NULL` to restore the default table. |

#### Returns

the previous pointer hook table

Since: 2.2

### gdk_display_warp_pointer ()

    void
    gdk_display_warp_pointer (GdkDisplay *display,
                              GdkScreen *screen,
                              gint x,
                              gint y);

Warps the pointer of `display` to the point `x` ,`y` on the screen `screen` , unless the pointer is confined to a window by a grab, in which case it will be moved as far as allowed by the grab. Warping the pointer creates events as if the user had moved the mouse instantaneously to the destination.

Note that the pointer should normally be under the control of the user. This function was added to cover some rare use cases like keyboard navigation support for the color picker in the GtkColorSelectionDialog.

#### Parameters

display | a GdkDisplay |
screen | the screen of `display` to warp the pointer to |
x | the x coordinate of the destination |
y | the y coordinate of the destination |

Since: 2.8

### gdk_display_supports_cursor_color ()

    gboolean
    gdk_display_supports_cursor_color (GdkDisplay *display);

Returns `TRUE` if multicolored cursors are supported on `display` . Otherwise, cursors have only a forground and a background color.

#### Parameters

display | a GdkDisplay |

#### Returns

whether cursors can have multiple colors.

Since: 2.4

### gdk_display_supports_cursor_alpha ()

    gboolean
    gdk_display_supports_cursor_alpha (GdkDisplay *display);

Returns `TRUE` if cursors can use an 8bit alpha channel on `display` . Otherwise, cursors are restricted to bilevel alpha (i.e. a mask).

#### Parameters

display | a GdkDisplay |

#### Returns

whether cursors can have alpha channels.

Since: 2.4

### gdk_display_get_default_cursor_size ()

    guint
    gdk_display_get_default_cursor_size (GdkDisplay *display);

Returns the default size to use for cursors on `display` .

#### Parameters

display | a GdkDisplay |

#### Returns

the default cursor size.

Since: 2.4

### gdk_display_get_maximal_cursor_size ()

    void
    gdk_display_get_maximal_cursor_size (GdkDisplay *display,
                                         guint *width,
                                         guint *height);

Gets the maximal size to use for cursors on `display` .

#### Parameters

display | a GdkDisplay |
width | the return location for the maximal cursor width. | [out]
height | the return location for the maximal cursor height. | [out]

Since: 2.4

### gdk_display_get_default_group ()

    GdkWindow *
    gdk_display_get_default_group (GdkDisplay *display);

Returns the default group leader window for all toplevel windows on `display` . This window is implicitly created by GDK. See `gdk_window_set_group()`.

#### Parameters

display | a GdkDisplay |

#### Returns

The default group leader window for `display`

Since: 2.4

### gdk_display_supports_selection_notification ()

    gboolean
    gdk_display_supports_selection_notification
                                   (GdkDisplay *display);

Returns whether GdkEventOwnerChange events will be sent when the owner of a selection changes.

#### Parameters

display | a GdkDisplay |

#### Returns

whether GdkEventOwnerChange events will be sent.

Since: 2.6

### gdk_display_request_selection_notification ()

    gboolean
    gdk_display_request_selection_notification
                                   (GdkDisplay *display,
                                    GdkAtom selection);

Request GdkEventOwnerChange events for ownership changes of the selection named by the given atom.

#### Parameters

display | a GdkDisplay |
selection | the GdkAtom naming the selection for which ownership change notification is requested |

#### Returns

whether GdkEventOwnerChange events will be sent.

Since: 2.6

### gdk_display_supports_clipboard_persistence ()

    gboolean
    gdk_display_supports_clipboard_persistence
                                   (GdkDisplay *display);

Returns whether the speicifed display supports clipboard persistance; i.e. if it's possible to store the clipboard data after an application has quit. On X11 this checks if a clipboard daemon is running.

#### Parameters

display | a GdkDisplay |

#### Returns

`TRUE` if the display supports clipboard persistance.

Since: 2.6

### gdk_display_store_clipboard ()

    void
    gdk_display_store_clipboard (GdkDisplay *display,
                                 GdkWindow *clipboard_window,
                                 guint32 time_,
                                 const GdkAtom *targets,
                                 gint n_targets);

Issues a request to the clipboard manager to store the clipboard data. On X11, this is a special program that works according to the freedesktop clipboard specification, available at

http://www.freedesktop.org/Standards/clipboard-manager-spec.

#### Parameters

display | a GdkDisplay |
clipboard_window | a GdkWindow belonging to the clipboard owner |
time_ | a timestamp |
targets | an array of targets that should be saved, or `NULL` if all available targets should be saved. |
n_targets | length of the `targets` array |

Since: 2.6

### gdk_display_supports_shapes ()

    gboolean
    gdk_display_supports_shapes (GdkDisplay *display);

Returns `TRUE` if `gdk_window_shape_combine_mask()` can be used to create shaped windows on `display` .

#### Parameters

display | a GdkDisplay |

#### Returns

`TRUE` if shaped windows are supported

Since: 2.10

### gdk_display_supports_input_shapes ()

    gboolean
    gdk_display_supports_input_shapes (GdkDisplay *display);

Returns `TRUE` if `gdk_window_input_shape_combine_mask()` can be used to modify the input shape of windows on `display` .

#### Parameters

display | a GdkDisplay |

#### Returns

`TRUE` if windows with modified input shape are supported

Since: 2.10

### gdk_display_supports_composite ()

    gboolean
    gdk_display_supports_composite (GdkDisplay *display);

Returns `TRUE` if `gdk_window_set_composited()` can be used to redirect drawing on the window using compositing.

Currently this only works on X11 with XComposite and XDamage extensions available.

#### Parameters

display | a GdkDisplay |

#### Returns

`TRUE` if windows may be composited.

Since: 2.12

## Types and Values

### GdkDisplay

    typedef struct _GdkDisplay GdkDisplay;

### struct GdkDisplayPointerHooks

    struct GdkDisplayPointerHooks {
      void (*get_pointer)              (GdkDisplay      *display,
    				    GdkScreen      **screen,
    				    gint            *x,
    				    gint            *y,
    				    GdkModifierType *mask);
      GdkWindow* (*window_get_pointer) (GdkDisplay      *display,
    				    GdkWindow       *window,
    				    gint            *x,
    				    gint            *y,
    				    GdkModifierType *mask);
      GdkWindow* (*window_at_pointer)  (GdkDisplay      *display,
    				    gint            *win_x,
    				    gint            *win_y);
    };

## 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

Since: 2.2