GdkScreen

GdkScreen — Object representing a physical screen

Synopsis


#include <gdk/gdk.h>


                    GdkScreen;
GdkScreen*          gdk_screen_get_default              (void);
GdkColormap*        gdk_screen_get_default_colormap     (GdkScreen *screen);
void                gdk_screen_set_default_colormap     (GdkScreen *screen,
                                                         GdkColormap *colormap);
GdkColormap*        gdk_screen_get_system_colormap      (GdkScreen *screen);
GdkVisual*          gdk_screen_get_system_visual        (GdkScreen *screen);
GdkColormap*        gdk_screen_get_rgb_colormap         (GdkScreen *screen);
GdkVisual*          gdk_screen_get_rgb_visual           (GdkScreen *screen);
GdkColormap*        gdk_screen_get_rgba_colormap        (GdkScreen *screen);
GdkVisual*          gdk_screen_get_rgba_visual          (GdkScreen *screen);
gboolean            gdk_screen_is_composited            (GdkScreen *screen);
GdkWindow*          gdk_screen_get_root_window          (GdkScreen *screen);
GdkDisplay*         gdk_screen_get_display              (GdkScreen *screen);
gint                gdk_screen_get_number               (GdkScreen *screen);
gint                gdk_screen_get_width                (GdkScreen *screen);
gint                gdk_screen_get_height               (GdkScreen *screen);
gint                gdk_screen_get_width_mm             (GdkScreen *screen);
gint                gdk_screen_get_height_mm            (GdkScreen *screen);
GList*              gdk_screen_list_visuals             (GdkScreen *screen);
GList*              gdk_screen_get_toplevel_windows     (GdkScreen *screen);
gchar*              gdk_screen_make_display_name        (GdkScreen *screen);
gint                gdk_screen_get_n_monitors           (GdkScreen *screen);
void                gdk_screen_get_monitor_geometry     (GdkScreen *screen,
                                                         gint monitor_num,
                                                         GdkRectangle *dest);
gint                gdk_screen_get_monitor_at_point     (GdkScreen *screen,
                                                         gint x,
                                                         gint y);
gint                gdk_screen_get_monitor_at_window    (GdkScreen *screen,
                                                         GdkWindow *window);
void                gdk_screen_broadcast_client_message (GdkScreen *screen,
                                                         GdkEvent *event);
gboolean            gdk_screen_get_setting              (GdkScreen *screen,
                                                         const gchar *name,
                                                         GValue *value);
const cairo_font_options_t* gdk_screen_get_font_options (GdkScreen *screen);
void                gdk_screen_set_font_options         (GdkScreen *screen,
                                                         const cairo_font_options_t *options);
gdouble             gdk_screen_get_resolution           (GdkScreen *screen);
void                gdk_screen_set_resolution           (GdkScreen *screen,
                                                         gdouble dpi);
GdkWindow*          gdk_screen_get_active_window        (GdkScreen *screen);
GList*              gdk_screen_get_window_stack         (GdkScreen *screen);

gboolean            gdk_spawn_on_screen                 (GdkScreen *screen,
                                                         const gchar *working_directory,
                                                         gchar **argv,
                                                         gchar **envp,
                                                         GSpawnFlags flags,
                                                         GSpawnChildSetupFunc child_setup,
                                                         gpointer user_data,
                                                         gint *child_pid,
                                                         GError **error);
gboolean            gdk_spawn_on_screen_with_pipes      (GdkScreen *screen,
                                                         const gchar *working_directory,
                                                         gchar **argv,
                                                         gchar **envp,
                                                         GSpawnFlags flags,
                                                         GSpawnChildSetupFunc child_setup,
                                                         gpointer user_data,
                                                         gint *child_pid,
                                                         gint *standard_input,
                                                         gint *standard_output,
                                                         gint *standard_error,
                                                         GError **error);
gboolean            gdk_spawn_command_line_on_screen    (GdkScreen *screen,
                                                         const gchar *command_line,
                                                         GError **error);


Object Hierarchy


  GObject
   +----GdkScreen

Properties


  "font-options"             gpointer              : Read / Write
  "resolution"               gdouble               : Read / Write

Signals


  "composited-changed"                             : Run Last
  "size-changed"                                   : Run Last

Description

GdkScreen objects are the GDK representation of a physical screen. It is used throughout GDK and GTK+ to specify which screen the top level windows are to be displayed on. It is also used to query the screen specification and default settings such as the default colormap (gdk_screen_get_default_colormap()), the screen width (gdk_screen_get_width()), etc.

Note that a screen may consist of multiple monitors which are merged to form a large screen area.

Details

GdkScreen

typedef struct _GdkScreen GdkScreen;

This is a currently just a placeholder typedef for the first argument of the window_at_pointer function in GdkPointerHooks. It will be used when GDK gets multihead support.

Since 2.2


gdk_screen_get_default ()

GdkScreen*          gdk_screen_get_default              (void);

Gets the default screen for the default display. (See gdk_display_get_default()).

Returns :

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

Since 2.2


gdk_screen_get_default_colormap ()

GdkColormap*        gdk_screen_get_default_colormap     (GdkScreen *screen);

Gets the default colormap for screen.

screen :

a GdkScreen

Returns :

the default GdkColormap.

Since 2.2


gdk_screen_set_default_colormap ()

void                gdk_screen_set_default_colormap     (GdkScreen *screen,
                                                         GdkColormap *colormap);

Sets the default colormap for screen.

screen :

a GdkScreen

colormap :

a GdkColormap

Since 2.2


gdk_screen_get_system_colormap ()

GdkColormap*        gdk_screen_get_system_colormap      (GdkScreen *screen);

Gets the system's default colormap for screen

screen :

a GdkScreen

Returns :

the default colormap for screen.

Since 2.2


gdk_screen_get_system_visual ()

GdkVisual*          gdk_screen_get_system_visual        (GdkScreen *screen);

Get the system's default visual for screen. This is the visual for the root window of the display. The return value should not be freed.

screen :

a GdkScreen.

Returns :

the system visual

Since 2.2


gdk_screen_get_rgb_colormap ()

GdkColormap*        gdk_screen_get_rgb_colormap         (GdkScreen *screen);

Gets the preferred colormap for rendering image data on screen. Not a very useful function; historically, GDK could only render RGB image data to one colormap and visual, but in the current version it can render to any colormap and visual. So there's no need to call this function.

screen :

a GdkScreen.

Returns :

the preferred colormap

Since 2.2


gdk_screen_get_rgb_visual ()

GdkVisual*          gdk_screen_get_rgb_visual           (GdkScreen *screen);

Gets a "preferred visual" chosen by GdkRGB for rendering image data on screen. In previous versions of GDK, this was the only visual GdkRGB could use for rendering. In current versions, it's simply the visual GdkRGB would have chosen as the optimal one in those previous versions. GdkRGB can now render to drawables with any visual.

screen :

a GdkScreen

Returns :

The GdkVisual chosen by GdkRGB.

Since 2.2


gdk_screen_get_rgba_colormap ()

GdkColormap*        gdk_screen_get_rgba_colormap        (GdkScreen *screen);

Gets a colormap to use for creating windows or pixmaps with an alpha channel. The windowing system on which GTK+ is running may not support this capability, in which case NULL will be returned. Even if a non-NULL value is returned, its possible that the window's alpha channel won't be honored when displaying the window on the screen: in particular, for X an appropriate windowing manager and compositing manager must be running to provide appropriate display.

This functionality is not implemented in the Windows backend.

For setting an overall opacity for a top-level window, see gdk_window_set_opacity().

screen :

a GdkScreen.

Returns :

a colormap to use for windows with an alpha channel or NULL if the capability is not available.

Since 2.8


gdk_screen_get_rgba_visual ()

GdkVisual*          gdk_screen_get_rgba_visual          (GdkScreen *screen);

Gets a visual to use for creating windows or pixmaps with an alpha channel. See the docs for gdk_screen_get_rgba_colormap() for caveats.

screen :

a GdkScreen

Returns :

a visual to use for windows with an alpha channel or NULL if the capability is not available.

Since 2.8


gdk_screen_is_composited ()

gboolean            gdk_screen_is_composited            (GdkScreen *screen);

Returns whether windows with an RGBA visual can reasonably be expected to have their alpha channel drawn correctly on the screen.

On X11 this function returns whether a compositing manager is compositing screen.

screen :

a GdkScreen

Returns :

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

Since 2.10


gdk_screen_get_root_window ()

GdkWindow*          gdk_screen_get_root_window          (GdkScreen *screen);

Gets the root window of screen.

screen :

a GdkScreen

Returns :

the root window

Since 2.2


gdk_screen_get_display ()

GdkDisplay*         gdk_screen_get_display              (GdkScreen *screen);

Gets the display to which the screen belongs.

screen :

a GdkScreen

Returns :

the display to which screen belongs

Since 2.2


gdk_screen_get_number ()

gint                gdk_screen_get_number               (GdkScreen *screen);

Gets the index of screen among the screens in the display to which it belongs. (See gdk_screen_get_display())

screen :

a GdkScreen

Returns :

the index

Since 2.2


gdk_screen_get_width ()

gint                gdk_screen_get_width                (GdkScreen *screen);

Gets the width of screen in pixels

screen :

a GdkScreen

Returns :

the width of screen in pixels.

Since 2.2


gdk_screen_get_height ()

gint                gdk_screen_get_height               (GdkScreen *screen);

Gets the height of screen in pixels

screen :

a GdkScreen

Returns :

the height of screen in pixels.

Since 2.2


gdk_screen_get_width_mm ()

gint                gdk_screen_get_width_mm             (GdkScreen *screen);

Gets the width of screen in millimeters. Note that on some X servers this value will not be correct.

screen :

a GdkScreen

Returns :

the width of screen in millimeters.

Since 2.2


gdk_screen_get_height_mm ()

gint                gdk_screen_get_height_mm            (GdkScreen *screen);

Returns the height of screen in millimeters. Note that on some X servers this value will not be correct.

screen :

a GdkScreen

Returns :

the heigth of screen in millimeters.

Since 2.2


gdk_screen_list_visuals ()

GList*              gdk_screen_list_visuals             (GdkScreen *screen);

Lists the available visuals for the specified screen. A visual describes a hardware image data format. For example, a visual might support 24-bit color, or 8-bit color, and might expect pixels to be in a certain format.

Call g_list_free() on the return value when you're finished with it.

screen :

the relevant GdkScreen.

Returns :

a list of visuals; the list must be freed, but not its contents

Since 2.2


gdk_screen_get_toplevel_windows ()

GList*              gdk_screen_get_toplevel_windows     (GdkScreen *screen);

Obtains a list of all toplevel windows known to GDK on the screen screen. A toplevel window is a child of the root window (see gdk_get_default_root_window()).

The returned list should be freed with g_list_free(), but its elements need not be freed.

screen :

The GdkScreen where the toplevels are located.

Returns :

list of toplevel windows, free with g_list_free()

Since 2.2


gdk_screen_make_display_name ()

gchar*              gdk_screen_make_display_name        (GdkScreen *screen);

Determines the name to pass to gdk_display_open() to get a GdkDisplay with this screen as the default screen.

screen :

a GdkScreen

Returns :

a newly allocated string, free with g_free()

Since 2.2


gdk_screen_get_n_monitors ()

gint                gdk_screen_get_n_monitors           (GdkScreen *screen);

Returns the number of monitors which screen consists of.

screen :

a GdkScreen.

Returns :

number of monitors which screen consists of.

Since 2.2


gdk_screen_get_monitor_geometry ()

void                gdk_screen_get_monitor_geometry     (GdkScreen *screen,
                                                         gint monitor_num,
                                                         GdkRectangle *dest);

Retrieves the GdkRectangle representing the size and position of the individual monitor within the entire screen area.

Note that the size of the entire screen area can be retrieved via gdk_screen_get_width() and gdk_screen_get_height().

screen :

a GdkScreen.

monitor_num :

the monitor number.

dest :

a GdkRectangle to be filled with the monitor geometry

Since 2.2


gdk_screen_get_monitor_at_point ()

gint                gdk_screen_get_monitor_at_point     (GdkScreen *screen,
                                                         gint x,
                                                         gint y);

Returns the monitor number in which the point (x,y) is located.

screen :

a GdkScreen.

x :

the x coordinate in the virtual screen.

y :

the y coordinate in the virtual screen.

Returns :

the monitor number in which the point (x,y) lies, or a monitor close to (x,y) if the point is not in any monitor.

Since 2.2


gdk_screen_get_monitor_at_window ()

gint                gdk_screen_get_monitor_at_window    (GdkScreen *screen,
                                                         GdkWindow *window);

Returns the number of the monitor in which the largest area of the bounding rectangle of window resides.

screen :

a GdkScreen.

window :

a GdkWindow

Returns :

the monitor number in which most of window is located, or if window does not intersect any monitors, a monitor, close to window.

Since 2.2


gdk_screen_broadcast_client_message ()

void                gdk_screen_broadcast_client_message (GdkScreen *screen,
                                                         GdkEvent *event);

On X11, sends an X ClientMessage event to all toplevel windows on screen.

Toplevel windows are determined by checking for the WM_STATE property, as described in the Inter-Client Communication Conventions Manual (ICCCM). If no windows are found with the WM_STATE property set, the message is sent to all children of the root window.

On Windows, broadcasts a message registered with the name GDK_WIN32_CLIENT_MESSAGE to all top-level windows. The amount of data is limited to one long, i.e. four bytes.

screen :

the GdkScreen where the event will be broadcasted.

event :

the GdkEvent.

Since 2.2


gdk_screen_get_setting ()

gboolean            gdk_screen_get_setting              (GdkScreen *screen,
                                                         const gchar *name,
                                                         GValue *value);

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

FIXME needs a list of valid settings here, or a link to more information.

screen :

the GdkScreen where the setting is located

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.

Since 2.2


gdk_screen_get_font_options ()

const cairo_font_options_t* gdk_screen_get_font_options (GdkScreen *screen);

Gets any options previously set with gdk_screen_set_font_options().

screen :

a GdkScreen

Returns :

the current font options, or NULL if no default font options have been set.

Since 2.10


gdk_screen_set_font_options ()

void                gdk_screen_set_font_options         (GdkScreen *screen,
                                                         const cairo_font_options_t *options);

Sets the default font options for the screen. These options will be set on any PangoContext's newly created with gdk_pango_context_get_for_screen(). Changing the default set of font options does not affect contexts that have already been created.

screen :

a GdkScreen

options :

a cairo_font_options_t, or NULL to unset any previously set default font options.

Since 2.10


gdk_screen_get_resolution ()

gdouble             gdk_screen_get_resolution           (GdkScreen *screen);

Gets the resolution for font handling on the screen; see gdk_screen_set_resolution() for full details.

screen :

a GdkScreen

Returns :

the current resolution, or -1 if no resolution has been set.

Since 2.10


gdk_screen_set_resolution ()

void                gdk_screen_set_resolution           (GdkScreen *screen,
                                                         gdouble dpi);

Sets the resolution for font handling on the screen. This is a scale factor between points specified in a PangoFontDescription and cairo units. The default value is 96, meaning that a 10 point font will be 13 units high. (10 * 96. / 72. = 13.3).

screen :

a GdkScreen

dpi :

the resolution in "dots per inch". (Physical inches aren't actually involved; the terminology is conventional.)

Since 2.10


gdk_screen_get_active_window ()

GdkWindow*          gdk_screen_get_active_window        (GdkScreen *screen);

Returns the screen's currently active window.

On X11, this is done by inspecting the _NET_ACTIVE_WINDOW property on the root window, as described in the Extended Window Manager Hints. If there is no currently currently active window, or the window manager does not support the _NET_ACTIVE_WINDOW hint, this function returns NULL.

On other platforms, this function may return NULL, depending on whether it is implementable on that platform.

The returned window should be unrefed using g_object_unref() when no longer needed.

screen :

a GdkScreen

Returns :

the currently active window, or NULL.

Since 2.10


gdk_screen_get_window_stack ()

GList*              gdk_screen_get_window_stack         (GdkScreen *screen);

Returns a GList of GdkWindows representing the current window stack.

On X11, this is done by inspecting the _NET_CLIENT_LIST_STACKING property on the root window, as described in the Extended Window Manager Hints. If the window manager does not support the _NET_CLIENT_LIST_STACKING hint, this function returns NULL.

On other platforms, this function may return NULL, depending on whether it is implementable on that platform.

The returned list is newly allocated and owns references to the windows it contains, so it should be freed using g_list_free() and its windows unrefed using g_object_unref() when no longer needed.

screen :

a GdkScreen

Returns :

a list of GdkWindows for the current window stack, or NULL.

Since 2.10


gdk_spawn_on_screen ()

gboolean            gdk_spawn_on_screen                 (GdkScreen *screen,
                                                         const gchar *working_directory,
                                                         gchar **argv,
                                                         gchar **envp,
                                                         GSpawnFlags flags,
                                                         GSpawnChildSetupFunc child_setup,
                                                         gpointer user_data,
                                                         gint *child_pid,
                                                         GError **error);

Like g_spawn_async(), except the child process is spawned in such an environment that on calling gdk_display_open() it would be returned a GdkDisplay with screen as the default screen.

This is useful for applications which wish to launch an application on a specific screen.

screen :

a GdkScreen

working_directory :

child's current working directory, or NULL to inherit parent's

argv :

child's argument vector

envp :

child's environment, or NULL to inherit parent's

flags :

flags from GSpawnFlags

child_setup :

function to run in the child just before exec()

user_data :

user data for child_setup

child_pid :

return location for child process ID, or NULL

error :

return location for error

Returns :

TRUE on success, FALSE if error is set

Since 2.4


gdk_spawn_on_screen_with_pipes ()

gboolean            gdk_spawn_on_screen_with_pipes      (GdkScreen *screen,
                                                         const gchar *working_directory,
                                                         gchar **argv,
                                                         gchar **envp,
                                                         GSpawnFlags flags,
                                                         GSpawnChildSetupFunc child_setup,
                                                         gpointer user_data,
                                                         gint *child_pid,
                                                         gint *standard_input,
                                                         gint *standard_output,
                                                         gint *standard_error,
                                                         GError **error);

Like g_spawn_async_with_pipes(), except the child process is spawned in such an environment that on calling gdk_display_open() it would be returned a GdkDisplay with screen as the default screen.

This is useful for applications which wish to launch an application on a specific screen.

screen :

a GdkScreen

working_directory :

child's current working directory, or NULL to inherit parent's

argv :

child's argument vector

envp :

child's environment, or NULL to inherit parent's

flags :

flags from GSpawnFlags

child_setup :

function to run in the child just before exec()

user_data :

user data for child_setup

child_pid :

return location for child process ID, or NULL

standard_input :

return location for file descriptor to write to child's stdin, or NULL

standard_output :

return location for file descriptor to read child's stdout, or NULL

standard_error :

return location for file descriptor to read child's stderr, or NULL

error :

return location for error

Returns :

TRUE on success, FALSE if an error was set

Since 2.4


gdk_spawn_command_line_on_screen ()

gboolean            gdk_spawn_command_line_on_screen    (GdkScreen *screen,
                                                         const gchar *command_line,
                                                         GError **error);

Like g_spawn_command_line_async(), except the child process is spawned in such an environment that on calling gdk_display_open() it would be returned a GdkDisplay with screen as the default screen.

This is useful for applications which wish to launch an application on a specific screen.

screen :

a GdkScreen

command_line :

a command line

error :

return location for errors

Returns :

TRUE on success, FALSE if error is set.

Since 2.4

Property Details

The "font-options" property

  "font-options"             gpointer              : Read / Write

The default font options for the screen.


The "resolution" property

  "resolution"               gdouble               : Read / Write

The resolution for fonts on the screen.

Default value: -1

Signal Details

The "composited-changed" signal

void                user_function                      (GdkScreen *screen,
                                                        gpointer   user_data)      : Run Last

The ::composited_changed signal is emitted when the composited status of the screen changes

screen :

the object on which the signal is emitted

user_data :

user data set when the signal handler was connected.

Since 2.10


The "size-changed" signal

void                user_function                      (GdkScreen *screen,
                                                        gpointer   user_data)      : Run Last

The ::size_changed signal is emitted when the pixel width or height of a screen changes.

screen :

the object on which the signal is emitted

user_data :

user data set when the signal handler was connected.

Since 2.2