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# Gdk::Screen Class Reference

Inheritance diagram for Gdk::Screen:

[legend]

List of all members.

## Detailed Description

Object representing a physical screen Gdk::Screen 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 (get_default_colormap()), the screen width (get_width()), etc. Note that a screen may consist of multiple monitors which are merged to form a large screen area.

## Public Member Functions

void | broadcast_client_message (GdkEvent* event)
| On X11, sends an X ClientMessage event to all toplevel windows on screen.
Glib::RefPtr<const Gdk::Window> | get_active_window () const
| Return value: the currently active window, or `0`.
Glib::RefPtr<Gdk::Window> | get_active_window ()
| Return value: the currently active window, or `0`.
Glib::RefPtr<const Colormap> | get_default_colormap () const
| Gets the default colormap for screen.
Glib::RefPtr<Colormap> | get_default_colormap ()
| Gets the default colormap for screen.
Glib::RefPtr<const Display> | get_display () const
| Gets the display to which the screen belongs.
Glib::RefPtr<Display> | get_display ()
| Gets the display to which the screen belongs.
Cairo::FontOptions | get_font_options () const
| Gets any options previously set with set_font_options().
int | get_height () const
| Gets the height of screen in pixels.
int | get_height_mm () const
| Returns: the heigth of screen in millimeters.
int | get_monitor_at_point (int x, int y) const
| Returns: the monitor number in which the point ( x, y) lies, or.
int | get_monitor_at_window (const Glib::RefPtr<Window>& window) const
void | get_monitor_geometry (int monitor_num, Rectangle& dest) const
| Retrieves the Gdk::Rectangle representing the size and position of the individual monitor within the entire screen area.
int | get_n_monitors () const
| Returns: number of monitors which screen consists of.
int | get_number () const
| Gets the index of screen among the screens in the display to which it belongs.
double | get_resolution () const
| Gets the resolution for font handling on the screen; see set_resolution() for full details.
Glib::RefPtr<const Colormap> | get_rgb_colormap () const
| Gets the preferred colormap for rendering image data on screen.
Glib::RefPtr<Colormap> | get_rgb_colormap ()
| Gets the preferred colormap for rendering image data on screen.
Glib::RefPtr<const Visual> | get_rgb_visual () const
| Gets a "preferred visual" chosen by GdkRGB for rendering image data on screen.
Glib::RefPtr<Visual> | get_rgb_visual ()
| Gets a "preferred visual" chosen by GdkRGB for rendering image data on screen.
Glib::RefPtr<const Colormap> | get_rgba_colormap () const
| Gets a colormap to use for creating windows or pixmaps with an alpha channel.
Glib::RefPtr<Colormap> | get_rgba_colormap ()
| Gets a colormap to use for creating windows or pixmaps with an alpha channel.
Glib::RefPtr<const Visual> | get_rgba_visual () const
| Gets a visual to use for creating windows or pixmaps with an alpha channel.
Glib::RefPtr<Visual> | get_rgba_visual ()
| Gets a visual to use for creating windows or pixmaps with an alpha channel.
Glib::RefPtr<const Window> | get_root_window () const
| Gets the root window of screen.
Glib::RefPtr<Window> | get_root_window ()
| Gets the root window of screen.
template<class ValueType>
bool | get_setting (const Glib::ustring& name, ValueType& value) const
Glib::RefPtr<const Colormap> | get_system_colormap () const
| Gets the system's default colormap for screen.
Glib::RefPtr<Colormap> | get_system_colormap ()
| Gets the system's default colormap for screen.
Glib::RefPtr<const Visual> | get_system_visual () const
| Get the system's default visual for screen.
Glib::RefPtr<Visual> | get_system_visual ()
| Get the system's default visual for screen.
Glib::ListHandle< Glib::RefPtr <Window >> | get_toplevel_windows ()
| Obtains a list of all toplevel windows known to GDK on the screen screen.
int | get_width () const
| Gets the width of screen in pixels.
int | get_width_mm () const
| Gets the width of screen in millimeters.
Glib::ListHandle< Glib::RefPtr <Window >> | get_window_stack ()
| Return value: a list of Gdk::Window<!-- -->s for the current window stack,.
const GdkScreen* | gobj () const
| Provides access to the underlying C GObject.
GdkScreen* | gobj ()
| Provides access to the underlying C GObject.
GdkScreen* | gobj_copy ()
| Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.
bool | is_composited () const
| Return value: Whether windows with RGBA visuals can reasonably be.
Glib::ListHandle< Glib::RefPtr <Visual >> | list_visuals ()
| Lists the available visuals for the specified screen.
Glib::ustring | make_display_name ()
| Determines the name to pass to Gdk::Display::open() to get a Gdk::Display with this screen as the default screen.
void | set_default_colormap (const Glib::RefPtr<const Colormap>& colormap)
| Sets the default colormap for screen.
void | set_font_options (const Cairo::FontOptions& options)
| Sets the default font options for the screen.
void | set_resolution (double dpi)
Glib::SignalProxy0<void> | signal_size_changed ()
| The size_changed signal is emitted when the pixel width or height of a screen changes.
virtual | ~Screen ()

## Static Public Member Functions

static Glib::RefPtr<Screen> | get_default ()
| Gets the default screen for the default display.

## Protected Member Functions

virtual void | on_size_changed ()

## Related Functions

(Note that these are not member functions.)
Glib::RefPtr<Gdk::Screen> | wrap (GdkScreen* object, bool take_copy=false)
| A Glib::wrap() method for this object.

## Constructor & Destructor Documentation

virtual Gdk::Screen::~Screen | ( |  | ) | `[virtual]`

## Member Function Documentation

void Gdk::Screen::broadcast_client_message | ( | 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.

Since gtkmm 2.2:

Parameters:

  | event | The Gdk::Event.

Glib::RefPtr<const Gdk::Window> Gdk::Screen::get_active_window | ( |  | ) | const

Return value: the currently active window, or `0`.

Returns:
  The currently active window, or `0`.

Since gtkmm 2.10:

Glib::RefPtr<Gdk::Window> Gdk::Screen::get_active_window | ( |  | ) |

Return value: the currently active window, or `0`.

Returns:
  The currently active window, or `0`.

Since gtkmm 2.10:

static Glib::RefPtr<Screen> Gdk::Screen::get_default | ( |  | ) | `[static]`

Gets the default screen for the default display.

(See Gdk::Display::get_default()).

Returns:
  A Gdk::Screen, or `0` if there is no default display.

Since gtkmm 2.2:

Glib::RefPtr<const Colormap> Gdk::Screen::get_default_colormap | ( |  | ) | const

Gets the default colormap for screen.

Returns:
  The default Gdk::Colormap.

Since gtkmm 2.2:

Glib::RefPtr<Colormap> Gdk::Screen::get_default_colormap | ( |  | ) |

Gets the default colormap for screen.

Returns:
  The default Gdk::Colormap.

Since gtkmm 2.2:

Glib::RefPtr<const Display> Gdk::Screen::get_display | ( |  | ) | const

Gets the display to which the screen belongs.

Returns:
  The display to which screen belongs

Since gtkmm 2.2:

Glib::RefPtr<Display> Gdk::Screen::get_display | ( |  | ) |

Gets the display to which the screen belongs.

Returns:
  The display to which screen belongs

Since gtkmm 2.2:

Cairo::FontOptions Gdk::Screen::get_font_options | ( |  | ) | const

Gets any options previously set with set_font_options().

Returns:
  The current font options, or `0` if no default font options have been set.

Since gtkmm 2.10:

int Gdk::Screen::get_height | ( |  | ) | const

Gets the height of screen in pixels.

Returns:
  The height of screen in pixels.

Since gtkmm 2.2:

int Gdk::Screen::get_height_mm | ( |  | ) | const

Returns: the heigth of screen in millimeters.

Returns:
  The heigth of screen in millimeters.

Since gtkmm 2.2:

int Gdk::Screen::get_monitor_at_point | ( | int | x,
|  | int | y |
| ) |  |  | const

Returns: the monitor number in which the point ( x, y) lies, or.

Parameters:

  | 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 gtkmm 2.2:

int Gdk::Screen::get_monitor_at_window | ( | const Glib::RefPtr<Window>& | window | ) | const

Parameters:

  | window | A Gdk::Window.

Returns:
  The monitor number in which most of window is located, or if window does not intersect any monitors, a monitor, close to window. the number of the monitor in which the largest area of the bounding rectangle of window resides.

Since gtkmm 2.2:

void Gdk::Screen::get_monitor_geometry | ( | int | monitor_num,
|  | Rectangle& | dest |
| ) |  |  | const

Retrieves the Gdk::Rectangle 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 get_width() and get_height().

Since gtkmm 2.2:

Parameters:

  | monitor_num | The monitor number.
  | dest | A Gdk::Rectangle to be filled with the monitor geometry.

int Gdk::Screen::get_n_monitors | ( |  | ) | const

Returns: number of monitors which screen consists of.

Returns:
  Number of monitors which screen consists of.

Since gtkmm 2.2:

int Gdk::Screen::get_number | ( |  | ) | const

Gets the index of screen among the screens in the display to which it belongs.

(See get_display())

Returns:
  The index

Since gtkmm 2.2:

double Gdk::Screen::get_resolution | ( |  | ) | const

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

Returns:
  The current resolution, or -1 if no resolution has been set.

Since gtkmm 2.10:

Glib::RefPtr<const Colormap> Gdk::Screen::get_rgb_colormap | ( |  | ) | const

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.

Returns:
  The preferred colormap

Since gtkmm 2.2:

Glib::RefPtr<Colormap> Gdk::Screen::get_rgb_colormap | ( |  | ) |

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.

Returns:
  The preferred colormap

Since gtkmm 2.2:

Glib::RefPtr<const Visual> Gdk::Screen::get_rgb_visual | ( |  | ) | const

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.

Returns:
  The Gdk::Visual chosen by GdkRGB.

Since gtkmm 2.2:

Glib::RefPtr<Visual> Gdk::Screen::get_rgb_visual | ( |  | ) |

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.

Returns:
  The Gdk::Visual chosen by GdkRGB.

Since gtkmm 2.2:

Glib::RefPtr<const Colormap> Gdk::Screen::get_rgba_colormap | ( |  | ) | const

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 `0` will be returned. Even if a non-`0` 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().

Returns:
  A colormap to use for windows with an alpha channel or `0` if the capability is not available.

Since gtkmm 2.8:

Glib::RefPtr<Colormap> Gdk::Screen::get_rgba_colormap | ( |  | ) |

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 `0` will be returned. Even if a non-`0` 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().

Returns:
  A colormap to use for windows with an alpha channel or `0` if the capability is not available.

Since gtkmm 2.8:

Glib::RefPtr<const Visual> Gdk::Screen::get_rgba_visual | ( |  | ) | const

Gets a visual to use for creating windows or pixmaps with an alpha channel.

See the docs for get_rgba_colormap() for caveats.

Returns:
  A visual to use for windows with an alpha channel or `0` if the capability is not available.

Since gtkmm 2.8:

Glib::RefPtr<Visual> Gdk::Screen::get_rgba_visual | ( |  | ) |

Gets a visual to use for creating windows or pixmaps with an alpha channel.

See the docs for get_rgba_colormap() for caveats.

Returns:
  A visual to use for windows with an alpha channel or `0` if the capability is not available.

Since gtkmm 2.8:

Glib::RefPtr<const Window> Gdk::Screen::get_root_window | ( |  | ) | const

Gets the root window of screen.

Returns:
  The root window

Since gtkmm 2.2:

Glib::RefPtr<Window> Gdk::Screen::get_root_window | ( |  | ) |

Gets the root window of screen.

Returns:
  The root window

Since gtkmm 2.2:

template <class ValueType>

bool Gdk::Screen::get_setting | ( | const Glib::ustring & | name,
|  | ValueType & | value |
| ) |  |  | const`[inline]`

References Glib::ustring::c_str(), Glib::Value<T>::get(), Glib::ValueBase::gobj(), gobj(), and Glib::ValueBase::init().

Glib::RefPtr<const Colormap> Gdk::Screen::get_system_colormap | ( |  | ) | const

Gets the system's default colormap for screen.

Returns:
  The default colormap for screen.

Since gtkmm 2.2:

Glib::RefPtr<Colormap> Gdk::Screen::get_system_colormap | ( |  | ) |

Gets the system's default colormap for screen.

Returns:
  The default colormap for screen.

Since gtkmm 2.2:

Glib::RefPtr<const Visual> Gdk::Screen::get_system_visual | ( |  | ) | const

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.

Returns:
  The system visual

Since gtkmm 2.2:

Glib::RefPtr<Visual> Gdk::Screen::get_system_visual | ( |  | ) |

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.

Returns:
  The system visual

Since gtkmm 2.2:

Glib::ListHandle<Glib::RefPtr<Window>> Gdk::Screen::get_toplevel_windows | ( |  | ) |

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()). newin2p2

Returns:
  List of toplevel windows.

int Gdk::Screen::get_width | ( |  | ) | const

Gets the width of screen in pixels.

Returns:
  The width of screen in pixels.

Since gtkmm 2.2:

int Gdk::Screen::get_width_mm | ( |  | ) | const

Gets the width of screen in millimeters.

Note that on some X servers this value will not be correct.

Returns:
  The width of screen in millimeters.

Since gtkmm 2.2:

Glib::ListHandle<Glib::RefPtr<Window>> Gdk::Screen::get_window_stack | ( |  | ) |

Return value: a list of Gdk::Window<!-- -->s for the current window stack,.

Returns:
  A list of Gdk::Window<!-- -->s for the current window stack, or `0`.

Since gtkmm 2.10:

const GdkScreen* Gdk::Screen::gobj | ( |  | ) | const`[inline]`

Provides access to the underlying C GObject.

Reimplemented from Glib::ObjectBase.

GdkScreen* Gdk::Screen::gobj | ( |  | ) | `[inline]`

Provides access to the underlying C GObject.

Reimplemented from Glib::ObjectBase.

Referenced by get_setting().

GdkScreen* Gdk::Screen::gobj_copy | ( |  | ) |

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

bool Gdk::Screen::is_composited | ( |  | ) | const

Return value: Whether windows with RGBA visuals can reasonably be.

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

Since gtkmm 2.10:

Glib::ListHandle<Glib::RefPtr<Visual>> Gdk::Screen::list_visuals | ( |  | ) |

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. newin2p2

Returns:
  A list of visuals.

Glib::ustring Gdk::Screen::make_display_name | ( |  | ) |

Determines the name to pass to Gdk::Display::open() to get a Gdk::Display with this screen as the default screen.

newin2p2

Returns:
  The name.

virtual void Gdk::Screen::on_size_changed | ( |  | ) | `[protected, virtual]`

void Gdk::Screen::set_default_colormap | ( | const Glib::RefPtr<const Colormap>& | colormap | ) |

Sets the default colormap for screen.

Since gtkmm 2.2:

Parameters:

  | colormap | A Gdk::Colormap.

void Gdk::Screen::set_font_options | ( | const Cairo::FontOptions & | options | ) |

Sets the default font options for the screen.

These options will be set on any Pango::Context'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.

Since gtkmm 2.10:

Parameters:

  | options | A cairo_font_options_t, or `0` to unset any previously set default font options.

void Gdk::Screen::set_resolution | ( | double | dpi | ) |

Since gtkmm 2.10:

Parameters:

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

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

Glib::SignalProxy0< void > Gdk::Screen::signal_size_changed | ( |  | ) |

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

Prototype:
  `void on_my_size_changed()`

## Friends And Related Function Documentation

Glib::RefPtr<Gdk::Screen> wrap | ( | GdkScreen * | object,
|  | bool | take_copy = `false` |
| ) |  |  | `[related]`

A Glib::wrap() method for this object.

Parameters:

  | object | The C instance.
  | take_copy | False if the result should take ownership of the C instance. True if it should take a new copy or ref.

Returns:
  A C++ instance that wraps this C instance.

The documentation for this class was generated from the following file:

- screen.h