WnckScreen: Libwnck Reference Manual

WnckScreen

WnckScreen — an object representing a screen.

Stability Level

Unstable, unless otherwise indicated

Functions

WnckScreen *	wnck_screen_get_default ()
WnckScreen *	wnck_screen_get ()
WnckScreen *	wnck_screen_get_for_root ()
int	wnck_screen_get_number ()
int	wnck_screen_get_width ()
int	wnck_screen_get_height ()
void	wnck_screen_force_update ()
const char *	wnck_screen_get_window_manager_name ()
gboolean	wnck_screen_net_wm_supports ()
WnckWindow *	wnck_screen_get_active_window ()
WnckWindow *	wnck_screen_get_previously_active_window ()
GList *	wnck_screen_get_windows ()
GList *	wnck_screen_get_windows_stacked ()
WnckWorkspace *	wnck_screen_get_active_workspace ()
GList *	wnck_screen_get_workspaces ()
WnckWorkspace *	wnck_screen_get_workspace ()
int	wnck_screen_get_workspace_count ()
void	wnck_screen_change_workspace_count ()
int	wnck_screen_try_set_workspace_layout ()
void	wnck_screen_release_workspace_layout ()
void	wnck_screen_calc_workspace_layout ()
void	wnck_screen_free_workspace_layout ()
void	wnck_screen_move_viewport ()
gulong	wnck_screen_get_background_pixmap ()
gboolean	wnck_screen_get_showing_desktop ()
void	wnck_screen_toggle_showing_desktop ()

Signals

void	active-window-changed	Run Last
void	active-workspace-changed	Run Last
void	application-closed	Run Last
void	application-opened	Run Last
void	background-changed	Run Last
void	class-group-closed	Run Last
void	class-group-opened	Run Last
void	showing-desktop-changed	Run Last
void	viewports-changed	Run Last
void	window-closed	Run Last
void	window-manager-changed	Run Last
void	window-opened	Run Last
void	window-stacking-changed	Run Last
void	workspace-created	Run Last
void	workspace-destroyed	Run Last

Types and Values

struct	WnckScreen
struct	WnckWorkspaceLayout

Object Hierarchy

    GObject
    ╰── WnckScreen

Includes

#include <libwnck/libwnck.h>

Description

The WnckScreen represents a physical screen. A screen may consist of multiple monitors which are merged to form a large screen area. The WnckScreen is at the bottom of the libwnck stack of objects: WnckWorkspace objects exist a WnckScreen and WnckWindow objects are displayed on a WnckWorkspace.

The WnckScreen corresponds to the notion of

GdkScreen in GDK.

The WnckScreen objects are always owned by libwnck and must not be referenced or unreferenced.

Functions

wnck_screen_get_default ()

WnckScreen *
wnck_screen_get_default (void);

Gets the default WnckScreen on the default display.

Returns

the default WnckScreen. The returned WnckScreen is owned by libwnck and must not be referenced or unreferenced. This can return NULL if not on X11.

[transfer none][nullable]

wnck_screen_get ()

WnckScreen *
wnck_screen_get (int index);

Gets the WnckScreen for a given screen on the default display.

Parameters

index

screen number, starting from 0.

Returns

the WnckScreen for screen index , or NULL if no such screen exists. The returned WnckScreen is owned by libwnck and must not be referenced or unreferenced.

[transfer none]

wnck_screen_get_for_root ()

WnckScreen *
wnck_screen_get_for_root (gulong root_window_id);

Gets the WnckScreen for the root window at root_window_id , or NULL if no WnckScreen exists for this root window.

This function does not work if wnck_screen_get() was not called for the sought WnckScreen before, and returns NULL.

Parameters

root_window_id

an X window ID.

Returns

the WnckScreen for the root window at root_window_id , or NULL. The returned WnckScreen is owned by libwnck and must not be referenced or unreferenced.

[transfer none]

wnck_screen_get_number ()

int
wnck_screen_get_number (WnckScreen *screen);

Gets the index of screen on the display to which it belongs. The first WnckScreen has an index of 0.

Parameters

screen

a WnckScreen.

Returns

the index of space on screen , or -1 on errors.

Since: 2.20

wnck_screen_get_width ()

int
wnck_screen_get_width (WnckScreen *screen);

Gets the width of screen .

Parameters

screen

a WnckScreen.

Returns

the width of screen .

wnck_screen_get_height ()

int
wnck_screen_get_height (WnckScreen *screen);

Gets the height of screen .

Parameters

screen

a WnckScreen.

Returns

the height of screen .

wnck_screen_force_update ()

void
wnck_screen_force_update (WnckScreen *screen);

Synchronously and immediately updates the list of WnckWindow on screen . This bypasses the standard update mechanism, where the list of WnckWindow is updated in the idle loop.

This is usually a bad idea for both performance and correctness reasons (to get things right, you need to write model-view code that tracks changes, not get a static list of open windows). However, this function can be useful for small applications that just do something and then exit.

Parameters

screen

a WnckScreen.

wnck_screen_get_window_manager_name ()

const char *
wnck_screen_get_window_manager_name (WnckScreen *screen);

Gets the name of the window manager.

Parameters

screen

a WnckScreen.

Returns

the name of the window manager, or NULL if the window manager does not comply with the EWMH specification.

Since: 2.20

wnck_screen_net_wm_supports ()

gboolean
wnck_screen_net_wm_supports (WnckScreen *screen,
                             const char *atom);

Gets whether the window manager for screen supports a certain hint from the Extended Window Manager Hints specification (EWMH).

When using this function, keep in mind that the window manager can change over time; so you should not use this function in a way that impacts persistent application state. A common bug is that your application can start up before the window manager does when the user logs in, and before the window manager starts wnck_screen_net_wm_supports() will return FALSE for every property.

See also gdk_x11_screen_supports_net_wm_hint() in GDK.

Parameters

screen	a WnckScreen.
atom	a property atom.

Returns

TRUE if the window manager for screen supports the atom hint, FALSE otherwise.

wnck_screen_get_active_window ()

WnckWindow *
wnck_screen_get_active_window (WnckScreen *screen);

Gets the active WnckWindow on screen . May return NULL sometimes, since not all window managers guarantee that a window is always active.

Parameters

screen

a WnckScreen.

Returns

the active WnckWindow on screen , or NULL. The returned WnckWindow is owned by libwnck and must not be referenced or unreferenced.

[transfer none]

wnck_screen_get_previously_active_window ()

WnckWindow *
wnck_screen_get_previously_active_window
                               (WnckScreen *screen);

Gets the previously active WnckWindow on screen . May return NULL sometimes, since not all window managers guarantee that a window is always active.

Parameters

screen

a WnckScreen.

Returns

the previously active WnckWindow on screen , or NULL. The returned WnckWindow is owned by libwnck and must not be referenced or unreferenced.

[transfer none]

Since: 2.8

wnck_screen_get_windows ()

GList *
wnck_screen_get_windows (WnckScreen *screen);

a WnckScreen.

Returns

the list of WnckWorkspace on screen . The list should not be modified nor freed, as it is owned by screen .

[element-type WnckWorkspace][transfer none]

Since: 2.20

wnck_screen_get_workspace ()

WnckWorkspace *
wnck_screen_get_workspace (WnckScreen *screen,
                           int workspace);

Gets the WnckWorkspace numbered workspace on screen .

Parameters

screen	a WnckScreen.
workspace	a workspace index, starting from 0.

Returns

the WnckWorkspace numbered workspace on screen , or NULL if no such workspace exists. The returned WnckWorkspace is owned by libwnck and must not be referenced or unreferenced.

[transfer none]

wnck_screen_get_workspace_count ()

int
wnck_screen_get_workspace_count (WnckScreen *screen);

Gets the number of WnckWorkspace on screen .

Parameters

screen

a WnckScreen.

Returns

the number of WnckWorkspace on screen .

wnck_screen_change_workspace_count ()

void
wnck_screen_change_workspace_count (WnckScreen *screen,
                                    int count);

Asks the window manager to change the number of WnckWorkspace on screen .

Parameters

screen	a WnckScreen.
count	the number of WnckWorkspace to request.

Since: 2.2

wnck_screen_try_set_workspace_layout ()

int
wnck_screen_try_set_workspace_layout (WnckScreen *screen,
                                      int current_token,
                                      int rows,
                                      int columns);

Tries to modify the layout of WnckWorkspace on screen . To do this, tries to acquire ownership of the layout. If the current process is the owner of the layout, current_token is used to determine if the caller is the owner (there might be more than one part of the same process trying to set the layout). Since no more than one application should set this property of screen at a time, setting the layout is not guaranteed to work.

If rows is 0, the actual number of rows will be determined based on columns and the number of WnckWorkspace. If columns is 0, the actual number of columns will be determined based on rows and the number of WnckWorkspace. rows and columns must not be 0 at the same time.

You have to release the ownership of the layout with wnck_screen_release_workspace_layout() when you do not need it anymore.

Parameters

screen	a WnckScreen.
current_token	a token. Use 0 if you do not called `wnck_screen_try_set_workspace_layout()` before, or if you did not keep the old token.
rows	the number of rows to use for the WnckWorkspace layout.
columns	the number of columns to use for the WnckWorkspace layout.

Returns

a token to use for future calls to wnck_screen_try_set_workspace_layout() and to wnck_screen_release_workspace_layout(), or 0 if the layout could not be set.

wnck_screen_release_workspace_layout ()

void
wnck_screen_release_workspace_layout (WnckScreen *screen,
                                      int current_token);

Releases the ownership of the layout of WnckWorkspace on screen . current_token is used to verify that the caller is the owner of the layout. If the verification fails, nothing happens.

Parameters

screen	a WnckScreen.
current_token	the token obtained through `wnck_screen_try_set_workspace_layout()`.

wnck_screen_calc_workspace_layout ()

void
wnck_screen_calc_workspace_layout (WnckScreen *screen,
                                   int num_workspaces,
                                   int space_index,
                                   WnckWorkspaceLayout *layout);

wnck_screen_calc_workspace_layout has been deprecated since version 2.20 and should not be used in newly-written code.

Calculates the layout of WnckWorkspace, with additional information like the row and column of the WnckWorkspace with index space_index .

Parameters

screen	a WnckScreen.
num_workspaces	the number of WnckWorkspace on `screen` , or -1 to let `wnck_screen_calc_workspace_layout()` find this number.
space_index	the index of a WnckWorkspace.
layout	return location for the layout of WnckWorkspace with additional information.

Since: 2.12

wnck_screen_free_workspace_layout ()

void
wnck_screen_free_workspace_layout (WnckWorkspaceLayout *layout);

wnck_screen_free_workspace_layout has been deprecated since version 2.20 and should not be used in newly-written code.

Frees the content of layout . This does not free layout itself, so you might want to free layout yourself after calling this.

Parameters

layout

a WnckWorkspaceLayout.

Since: 2.12

wnck_screen_move_viewport ()

void
wnck_screen_move_viewport (WnckScreen *screen,
                           int x,
                           int y);

Asks the window manager to move the viewport of the current WnckWorkspace on screen .

Parameters

screen	a WnckScreen.
x	X offset in pixels of viewport.
y	Y offset in pixels of viewport.

Since: 2.4

wnck_screen_get_background_pixmap ()

gulong
wnck_screen_get_background_pixmap (WnckScreen *screen);

Gets the X window ID of the background pixmap of screen .

Parameters

screen

a WnckScreen.

Returns

the X window ID of the background pixmap of screen .

wnck_screen_get_showing_desktop ()

gboolean
wnck_screen_get_showing_desktop (WnckScreen *screen);

Gets whether screen is in the "showing the desktop" mode. This mode is changed when a “showing-desktop-changed” signal gets emitted.

Parameters

screen

a WnckScreen.

Returns

TRUE if window is fullscreen, FALSE otherwise.

Since: 2.2

wnck_screen_toggle_showing_desktop ()

void
wnck_screen_toggle_showing_desktop (WnckScreen *screen,
                                    gboolean show);

Asks the window manager to set the "showing the desktop" mode on screen according to show .

Parameters

screen	a WnckScreen.
show	whether to activate the "showing the desktop" mode on `screen` .

Since: 2.2

Types and Values

struct WnckScreen

struct WnckScreen;

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

struct WnckWorkspaceLayout

struct WnckWorkspaceLayout {
  int rows;
  int cols;
  int *grid;
  int grid_area;
  int current_row;
  int current_col;
};

WnckWorkspaceLayout has been deprecated since version 2.20 and should not be used in newly-written code.

The WnckWorkspaceLayout struct contains information about the layout of WnckWorkspace on a WnckScreen, and the exact position of a specific WnckWorkspace.

Members

int `rows`;	number of rows in the layout grid.
int `cols`;	number of columns in the layout grid.
int *`grid`;	array of size `grid_area` containing the index (starting from 0) of the WnckWorkspace for each position in the layout grid, or -1 if the position does not correspond to any WnckWorkspace.
int `grid_area`;	size of the grid containing all WnckWorkspace. This can be bigger than the number of WnckWorkspace because the grid might not be filled.
int `current_row`;	row of the specific WnckWorkspace, starting from 0.
int `current_col`;	column of the specific WnckWorkspace, starting from 0.

Since: 2.12

Signal Details

The `“active-window-changed”` signal

void
user_function (WnckScreen *screen,
               WnckWindow *previously_active_window,
               gpointer    user_data)

Emitted when the active window on screen has changed.

Parameters

screen	the WnckScreen which emitted the signal.
previously_active_window	the previously active WnckWindow before this change.
user_data	user data set when the signal handler was connected.

Flags: Run Last

The `“active-workspace-changed”` signal

void
user_function (WnckScreen    *screen,
               WnckWorkspace *previously_active_space,
               gpointer       user_data)

Emitted when the active workspace on screen has changed.

Parameters

screen	the WnckScreen which emitted the signal.
previously_active_space	the previously active WnckWorkspace before this change.
user_data	user data set when the signal handler was connected.

Flags: Run Last

The `“application-closed”` signal

void
user_function (WnckScreen      *screen,
               WnckApplication *app,
               gpointer         user_data)

Emitted when a WnckApplication is closed on screen .

Parameters

screen	the WnckScreen which emitted the signal.
app	the closed WnckApplication.
user_data	user data set when the signal handler was connected.

Flags: Run Last

The `“application-opened”` signal

void
user_function (WnckScreen      *screen,
               WnckApplication *app,
               gpointer         user_data)

Emitted when a new WnckApplication is opened on screen .

Parameters

screen	the WnckScreen which emitted the signal.
app	the opened WnckApplication.
user_data	user data set when the signal handler was connected.

Flags: Run Last

The `“background-changed”` signal

void
user_function (WnckScreen *screen,
               gpointer    user_data)

Emitted when the background on the root window of screen has changed.

Parameters

screen	the WnckScreen which emitted the signal.
user_data	user data set when the signal handler was connected.

Flags: Run Last

The `“class-group-closed”` signal

void
user_function (WnckScreen     *screen,
               WnckClassGroup *class_group,
               gpointer        user_data)

Emitted when a WnckClassGroup is closed on screen .

Parameters

screen	the WnckScreen which emitted the signal.
class_group	the closed WnckClassGroup.
user_data	user data set when the signal handler was connected.

Flags: Run Last

Since: 2.20

The `“class-group-opened”` signal

void
user_function (WnckScreen     *screen,
               WnckClassGroup *class_group,
               gpointer        user_data)

Emitted when a new WnckClassGroup is opened on screen .

Parameters

screen	the WnckScreen which emitted the signal.
class_group	the opened WnckClassGroup.
user_data	user data set when the signal handler was connected.

Flags: Run Last

Since: 2.20

The `“showing-desktop-changed”` signal

void
user_function (WnckScreen *screen,
               gpointer    user_data)

Emitted when "showing the desktop" mode of screen is toggled.

Parameters

screen	the WnckScreen which emitted the signal.
user_data	user data set when the signal handler was connected.

Flags: Run Last

Since: 2.20

The `“viewports-changed”` signal

void
user_function (WnckScreen *screen,
               gpointer    user_data)

Emitted when a viewport position has changed in a WnckWorkspace of screen or when a WnckWorkspace of screen gets or loses its viewport.

Parameters

screen	the WnckScreen which emitted the signal.
user_data	user data set when the signal handler was connected.

Flags: Run Last

Since: 2.20

The `“window-closed”` signal

void
user_function (WnckScreen *screen,
               WnckWindow *window,
               gpointer    user_data)

Emitted when a WnckWindow is closed on screen .

Parameters

screen	the WnckScreen which emitted the signal.
window	the closed WnckWindow.
user_data	user data set when the signal handler was connected.

Flags: Run Last

The `“window-manager-changed”` signal

void
user_function (WnckScreen *screen,
               gpointer    user_data)

Emitted when the window manager on screen has changed.

Parameters

screen	the WnckScreen which emitted the signal.
user_data	user data set when the signal handler was connected.

Flags: Run Last

Since: 2.20

The `“window-opened”` signal

void
user_function (WnckScreen *screen,
               WnckWindow *window,
               gpointer    user_data)

Emitted when a new WnckWindow is opened on screen .

Parameters

screen	the WnckScreen which emitted the signal.
window	the opened WnckWindow.
user_data	user data set when the signal handler was connected.

Flags: Run Last

The `“window-stacking-changed”` signal

void
user_function (WnckScreen *screen,
               gpointer    user_data)

Emitted when the stacking order of WnckWindow on screen has changed.

Parameters

screen	the WnckScreen which emitted the signal.
user_data	user data set when the signal handler was connected.

Flags: Run Last

The `“workspace-created”` signal

void
user_function (WnckScreen    *screen,
               WnckWorkspace *space,
               gpointer       user_data)

Emitted when a WnckWorkspace is created on screen .

Parameters

screen	the WnckScreen which emitted the signal.
space	the workspace that has been created.
user_data	user data set when the signal handler was connected.

Flags: Run Last

The `“workspace-destroyed”` signal

void
user_function (WnckScreen    *screen,
               WnckWorkspace *space,
               gpointer       user_data)

Emitted when a WnckWorkspace is destroyed on screen .

Parameters

screen	the WnckScreen which emitted the signal.
space	the workspace that has been destroyed.
user_data	user data set when the signal handler was connected.

Flags: Run Last