gtk/gdk/gdkscreen.c

/*
 * gdkscreen.c
 * 
 * Copyright 2001 Sun Microsystems Inc. 
 *
 * Erwann Chenede <erwann.chenede@sun.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include "gdkinternals.h"
#include "gdkscreenprivate.h"
#include "gdkrectangle.h"
#include "gdkwindow.h"
#include "gdkintl.h"


/**
 * SECTION:gdkscreen
 * @Short_description: Object representing a physical screen
 * @Title: GdkScreen
 *
 * #GdkScreen objects are the GDK representation of the screen on
 * which windows can be displayed and on which the pointer moves.
 * X originally identified screens with physical screens, but
 * nowadays it is more common to have a single #GdkScreen which
 * combines several physical monitors (see gdk_screen_get_n_monitors()).
 *
 * GdkScreen 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 visual (gdk_screen_get_system_visual()), the dimensions
 * of the physical monitors (gdk_screen_get_monitor_geometry()), etc.
 */


static void gdk_screen_finalize     (GObject        *object);
static void gdk_screen_set_property (GObject        *object,
				     guint           prop_id,
				     const GValue   *value,
				     GParamSpec     *pspec);
static void gdk_screen_get_property (GObject        *object,
				     guint           prop_id,
				     GValue         *value,
				     GParamSpec     *pspec);

enum
{
  PROP_0,
  PROP_FONT_OPTIONS,
  PROP_RESOLUTION
};

enum
{
  SIZE_CHANGED,
  COMPOSITED_CHANGED,
  MONITORS_CHANGED,
  LAST_SIGNAL
};

static guint signals[LAST_SIGNAL] = { 0 };

G_DEFINE_TYPE (GdkScreen, gdk_screen, G_TYPE_OBJECT)

static void
gdk_screen_class_init (GdkScreenClass *klass)
{
  GObjectClass *object_class = G_OBJECT_CLASS (klass);

  object_class->finalize = gdk_screen_finalize;
  object_class->set_property = gdk_screen_set_property;
  object_class->get_property = gdk_screen_get_property;
  
  g_object_class_install_property (object_class,
				   PROP_FONT_OPTIONS,
				   g_param_spec_pointer ("font-options",
							 P_("Font options"),
							 P_("The default font options for the screen"),
							 G_PARAM_READWRITE|G_PARAM_STATIC_NAME|
							G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB));

  g_object_class_install_property (object_class,
				   PROP_RESOLUTION,
				   g_param_spec_double ("resolution",
							P_("Font resolution"),
							P_("The resolution for fonts on the screen"),
							-G_MAXDOUBLE,
							G_MAXDOUBLE,
							-1.0,
							G_PARAM_READWRITE|G_PARAM_STATIC_NAME|
							G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB));

  /**
   * GdkScreen::size-changed:
   * @screen: the object on which the signal is emitted
   * 
   * The ::size-changed signal is emitted when the pixel width or 
   * height of a screen changes.
   *
   * Since: 2.2
   */
  signals[SIZE_CHANGED] =
    g_signal_new (g_intern_static_string ("size-changed"),
                  G_OBJECT_CLASS_TYPE (klass),
                  G_SIGNAL_RUN_LAST,
                  G_STRUCT_OFFSET (GdkScreenClass, size_changed),
                  NULL, NULL,
                  g_cclosure_marshal_VOID__VOID,
                  G_TYPE_NONE,
                  0);

  /**
   * GdkScreen::composited-changed:
   * @screen: the object on which the signal is emitted
   *
   * The ::composited-changed signal is emitted when the composited
   * status of the screen changes
   *
   * Since: 2.10
   */
  signals[COMPOSITED_CHANGED] =
    g_signal_new (g_intern_static_string ("composited-changed"),
		  G_OBJECT_CLASS_TYPE (klass),
		  G_SIGNAL_RUN_LAST,
		  G_STRUCT_OFFSET (GdkScreenClass, composited_changed),
		  NULL, NULL,
		  g_cclosure_marshal_VOID__VOID,
		  G_TYPE_NONE,
		  0);
	
  /**
   * GdkScreen::monitors-changed:
   * @screen: the object on which the signal is emitted
   *
   * The ::monitors-changed signal is emitted when the number, size
   * or position of the monitors attached to the screen change. 
   *
   * Only for X11 and OS X for now. A future implementation for Win32
   * may be a possibility.
   *
   * Since: 2.14
   */
  signals[MONITORS_CHANGED] =
    g_signal_new (g_intern_static_string ("monitors-changed"),
		  G_OBJECT_CLASS_TYPE (klass),
		  G_SIGNAL_RUN_LAST,
		  G_STRUCT_OFFSET (GdkScreenClass, monitors_changed),
		  NULL, NULL,
		  g_cclosure_marshal_VOID__VOID,
		  G_TYPE_NONE,
		  0);
}

static void
gdk_screen_init (GdkScreen *screen)
{
  screen->resolution = -1.;
}

static void
gdk_screen_finalize (GObject *object)
{
  GdkScreen *screen = GDK_SCREEN (object);

  if (screen->font_options)
      cairo_font_options_destroy (screen->font_options);

  G_OBJECT_CLASS (gdk_screen_parent_class)->finalize (object);
}

void 
_gdk_screen_close (GdkScreen *screen)
{
  g_return_if_fail (GDK_IS_SCREEN (screen));

  if (!screen->closed)
    {
      screen->closed = TRUE;
      g_object_run_dispose (G_OBJECT (screen));
    }
}

/* Fallback used when the monitor "at" a point or window
 * doesn't exist.
 */
static gint
get_nearest_monitor (GdkScreen *screen,
		     gint       x,
		     gint       y)
{
  gint num_monitors, i;
  gint nearest_dist = G_MAXINT;
  gint nearest_monitor = 0;

  g_return_val_if_fail (GDK_IS_SCREEN (screen), -1);

  num_monitors = gdk_screen_get_n_monitors (screen);
  
  for (i = 0; i < num_monitors; i++)
    {
      GdkRectangle monitor;
      gint dist_x, dist_y, dist;
      
      gdk_screen_get_monitor_geometry (screen, i, &monitor);

      if (x < monitor.x)
	dist_x = monitor.x - x;
      else if (x >= monitor.x + monitor.width)
	dist_x = x - (monitor.x + monitor.width) + 1;
      else
	dist_x = 0;

      if (y < monitor.y)
	dist_y = monitor.y - y;
      else if (y >= monitor.y + monitor.height)
	dist_y = y - (monitor.y + monitor.height) + 1;
      else
	dist_y = 0;

      dist = dist_x + dist_y;
      if (dist < nearest_dist)
	{
	  nearest_dist = dist;
	  nearest_monitor = i;
	}
    }

  return nearest_monitor;
}

/**
 * gdk_screen_get_monitor_at_point:
 * @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) is located.
 *
 * 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
 **/
gint 
gdk_screen_get_monitor_at_point (GdkScreen *screen,
				 gint       x,
				 gint       y)
{
  gint num_monitors, i;
  
  g_return_val_if_fail (GDK_IS_SCREEN (screen), -1);

  num_monitors = gdk_screen_get_n_monitors (screen);
  
  for (i=0;i<num_monitors;i++)
    {
      GdkRectangle monitor;
      
      gdk_screen_get_monitor_geometry (screen, i, &monitor);

      if (x >= monitor.x &&
          x < monitor.x + monitor.width &&
          y >= monitor.y &&
          y < (monitor.y + monitor.height))
        return i;
    }

  return get_nearest_monitor (screen, x, y);
}

/**
 * gdk_screen_get_monitor_at_window:
 * @screen: a #GdkScreen.
 * @window: a #GdkWindow
 *
 * Returns the number of the monitor in which the largest area of the
 * bounding rectangle of @window resides.
 *
 * 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
 **/
gint 
gdk_screen_get_monitor_at_window (GdkScreen      *screen,
				  GdkWindow	 *window)
{
  gint num_monitors, i, area = 0, screen_num = -1;
  GdkRectangle win_rect;

  g_return_val_if_fail (GDK_IS_SCREEN (screen), -1);

  gdk_window_get_geometry (window, &win_rect.x, &win_rect.y, &win_rect.width,
			   &win_rect.height);
  gdk_window_get_origin (window, &win_rect.x, &win_rect.y);
  num_monitors = gdk_screen_get_n_monitors (screen);
  
  for (i=0;i<num_monitors;i++)
    {
      GdkRectangle tmp_monitor, intersect;
      
      gdk_screen_get_monitor_geometry (screen, i, &tmp_monitor);
      gdk_rectangle_intersect (&win_rect, &tmp_monitor, &intersect);
      
      if (intersect.width * intersect.height > area)
	{ 
	  area = intersect.width * intersect.height;
	  screen_num = i;
	}
    }
  if (screen_num >= 0)
    return screen_num;
  else
    return get_nearest_monitor (screen,
				win_rect.x + win_rect.width / 2,
				win_rect.y + win_rect.height / 2);
}

/**
 * gdk_screen_width:
 * 
 * Returns the width of the default screen in pixels.
 * 
 * Return value: the width of the default screen in pixels.
 **/
gint
gdk_screen_width (void)
{
  return gdk_screen_get_width (gdk_screen_get_default ());
}

/**
 * gdk_screen_height:
 * 
 * Returns the height of the default screen in pixels.
 * 
 * Return value: the height of the default screen in pixels.
 **/
gint
gdk_screen_height (void)
{
  return gdk_screen_get_height (gdk_screen_get_default ());
}

/**
 * gdk_screen_width_mm:
 * 
 * Returns the width of the default screen in millimeters.
 * Note that on many X servers this value will not be correct.
 * 
 * Return value: the width of the default screen in millimeters,
 * though it is not always correct.
 **/
gint
gdk_screen_width_mm (void)
{
  return gdk_screen_get_width_mm (gdk_screen_get_default ());
}

/**
 * gdk_screen_height_mm:
 * 
 * Returns the height of the default screen in millimeters.
 * Note that on many X servers this value will not be correct.
 * 
 * Return value: the height of the default screen in millimeters,
 * though it is not always correct.
 **/
gint
gdk_screen_height_mm (void)
{
  return gdk_screen_get_height_mm (gdk_screen_get_default ());
}

/**
 * gdk_screen_set_font_options:
 * @screen: a #GdkScreen
 * @options: (allow-none): a #cairo_font_options_t, or %NULL to unset any
 *   previously set default font 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.
 *
 * Since: 2.10
 **/
void
gdk_screen_set_font_options (GdkScreen                  *screen,
			     const cairo_font_options_t *options)
{
  g_return_if_fail (GDK_IS_SCREEN (screen));

  if (screen->font_options != options)
    {
      if (screen->font_options)
        cairo_font_options_destroy (screen->font_options);

      if (options)
        screen->font_options = cairo_font_options_copy (options);
      else
        screen->font_options = NULL;

      g_object_notify (G_OBJECT (screen), "font-options");
    }
}

/**
 * gdk_screen_get_font_options:
 * @screen: a #GdkScreen
 * 
 * Gets any options previously set with gdk_screen_set_font_options().
 * 
 * Return value: the current font options, or %NULL if no default
 *  font options have been set.
 *
 * Since: 2.10
 **/
const cairo_font_options_t *
gdk_screen_get_font_options (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), NULL);

  return screen->font_options;
}

/**
 * gdk_screen_set_resolution:
 * @screen: a #GdkScreen
 * @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 #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).
 *
 * Since: 2.10
 **/
void
gdk_screen_set_resolution (GdkScreen *screen,
			   gdouble    dpi)
{
  g_return_if_fail (GDK_IS_SCREEN (screen));

  if (dpi < 0)
    dpi = -1.0;

  if (screen->resolution != dpi)
    {
      screen->resolution = dpi;

      g_object_notify (G_OBJECT (screen), "resolution");
    }
}

/**
 * gdk_screen_get_resolution:
 * @screen: a #GdkScreen
 * 
 * Gets the resolution for font handling on the screen; see
 * gdk_screen_set_resolution() for full details.
 * 
 * Return value: the current resolution, or -1 if no resolution
 * has been set.
 *
 * Since: 2.10
 **/
gdouble
gdk_screen_get_resolution (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), -1.0);

  return screen->resolution;
}

static void
gdk_screen_get_property (GObject      *object,
			 guint         prop_id,
			 GValue       *value,
			 GParamSpec   *pspec)
{
  GdkScreen *screen = GDK_SCREEN (object);

  switch (prop_id)
    {
    case PROP_FONT_OPTIONS:
      g_value_set_pointer (value, (gpointer) gdk_screen_get_font_options (screen));
      break;
    case PROP_RESOLUTION:
      g_value_set_double (value, gdk_screen_get_resolution (screen));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

static void
gdk_screen_set_property (GObject      *object,
			 guint         prop_id,
			 const GValue *value,
			 GParamSpec   *pspec)
{
  GdkScreen *screen = GDK_SCREEN (object);

  switch (prop_id)
    {
    case PROP_FONT_OPTIONS:
      gdk_screen_set_font_options (screen, g_value_get_pointer (value));
      break;
    case PROP_RESOLUTION:
      gdk_screen_set_resolution (screen, g_value_get_double (value));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
    }
}

/**
 * gdk_screen_get_display:
 * @screen: a #GdkScreen
 *
 * Gets the display to which the @screen belongs.
 *
 * Returns: (transfer none): the display to which @screen belongs
 *
 * Since: 2.2
 **/
GdkDisplay *
gdk_screen_get_display (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), NULL);

  return GDK_SCREEN_GET_CLASS (screen)->get_display (screen);
}


/**
 * gdk_screen_get_width:
 * @screen: a #GdkScreen
 *
 * Gets the width of @screen in pixels
 *
 * Returns: the width of @screen in pixels.
 *
 * Since: 2.2
 **/
gint
gdk_screen_get_width (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), 0);

  return GDK_SCREEN_GET_CLASS (screen)->get_width (screen);
}

/**
 * gdk_screen_get_height:
 * @screen: a #GdkScreen
 *
 * Gets the height of @screen in pixels
 *
 * Returns: the height of @screen in pixels.
 *
 * Since: 2.2
 **/
gint
gdk_screen_get_height (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), 0);

  return GDK_SCREEN_GET_CLASS (screen)->get_height (screen);
}

/**
 * gdk_screen_get_width_mm:
 * @screen: a #GdkScreen
 *
 * 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: 2.2
 **/
gint
gdk_screen_get_width_mm (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), 0);

  return GDK_SCREEN_GET_CLASS (screen)->get_width_mm (screen);
}

/**
 * gdk_screen_get_height_mm:
 * @screen: a #GdkScreen
 *
 * Returns the height of @screen in millimeters.
 * Note that on some X servers this value will not be correct.
 *
 * Returns: the heigth of @screen in millimeters.
 *
 * Since: 2.2
 **/
gint
gdk_screen_get_height_mm (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), 0);

  return GDK_SCREEN_GET_CLASS (screen)->get_height_mm (screen);
}

/**
 * gdk_screen_get_number:
 * @screen: a #GdkScreen
 *
 * Gets the index of @screen among the screens in the display
 * to which it belongs. (See gdk_screen_get_display())
 *
 * Returns: the index
 *
 * Since: 2.2
 **/
gint
gdk_screen_get_number (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), 0);

  return GDK_SCREEN_GET_CLASS (screen)->get_number (screen);
}

/**
 * gdk_screen_get_root_window:
 * @screen: a #GdkScreen
 *
 * Gets the root window of @screen.
 *
 * Returns: (transfer none): the root window
 *
 * Since: 2.2
 **/
GdkWindow *
gdk_screen_get_root_window (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), NULL);

  return GDK_SCREEN_GET_CLASS (screen)->get_root_window (screen);
}

/**
 * gdk_screen_get_n_monitors:
 * @screen: a #GdkScreen
 *
 * Returns the number of monitors which @screen consists of.
 *
 * Returns: number of monitors which @screen consists of
 *
 * Since: 2.2
 */
gint
gdk_screen_get_n_monitors (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), 0);

  return GDK_SCREEN_GET_CLASS (screen)->get_n_monitors (screen);
}

/**
 * gdk_screen_get_primary_monitor:
 * @screen: a #GdkScreen.
 *
 * Gets the primary monitor for @screen.  The primary monitor
 * is considered the monitor where the 'main desktop' lives.
 * While normal application windows typically allow the window
 * manager to place the windows, specialized desktop applications
 * such as panels should place themselves on the primary monitor.
 *
 * If no primary monitor is configured by the user, the return value
 * will be 0, defaulting to the first monitor.
 *
 * Returns: An integer index for the primary monitor, or 0 if none is configured.
 *
 * Since: 2.20
 */
gint
gdk_screen_get_primary_monitor (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), 0);

  return GDK_SCREEN_GET_CLASS (screen)->get_primary_monitor (screen);
}

/**
 * gdk_screen_get_monitor_width_mm:
 * @screen: a #GdkScreen
 * @monitor_num: number of the monitor, between 0 and gdk_screen_get_n_monitors (screen)
 *
 * Gets the width in millimeters of the specified monitor, if available.
 *
 * Returns: the width of the monitor, or -1 if not available
 *
 * Since: 2.14
 */
gint
gdk_screen_get_monitor_width_mm	(GdkScreen *screen,
				 gint       monitor_num)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), -1);
  g_return_val_if_fail (monitor_num >= 0, -1);
  g_return_val_if_fail (monitor_num < gdk_screen_get_n_monitors (screen), -1);

  return GDK_SCREEN_GET_CLASS (screen)->get_monitor_width_mm (screen, monitor_num);
}

/**
 * gdk_screen_get_monitor_height_mm:
 * @screen: a #GdkScreen
 * @monitor_num: number of the monitor, between 0 and gdk_screen_get_n_monitors (screen)
 *
 * Gets the height in millimeters of the specified monitor.
 *
 * Returns: the height of the monitor, or -1 if not available
 *
 * Since: 2.14
 */
gint
gdk_screen_get_monitor_height_mm (GdkScreen *screen,
                                  gint       monitor_num)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), -1);
  g_return_val_if_fail (monitor_num >= 0, -1);
  g_return_val_if_fail (monitor_num < gdk_screen_get_n_monitors (screen), -1);

  return GDK_SCREEN_GET_CLASS (screen)->get_monitor_height_mm (screen, monitor_num);
}

/**
 * gdk_screen_get_monitor_plug_name:
 * @screen: a #GdkScreen
 * @monitor_num: number of the monitor, between 0 and gdk_screen_get_n_monitors (screen)
 *
 * Returns the output name of the specified monitor.
 * Usually something like VGA, DVI, or TV, not the actual
 * product name of the display device.
 *
 * Returns: a newly-allocated string containing the name of the monitor,
 *   or %NULL if the name cannot be determined
 *
 * Since: 2.14
 */
gchar *
gdk_screen_get_monitor_plug_name (GdkScreen *screen,
				  gint       monitor_num)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), NULL);
  g_return_val_if_fail (monitor_num >= 0, NULL);
  g_return_val_if_fail (monitor_num < gdk_screen_get_n_monitors (screen), NULL);

  return GDK_SCREEN_GET_CLASS (screen)->get_monitor_plug_name (screen, monitor_num);
}

/**
 * gdk_screen_get_monitor_geometry:
 * @screen: a #GdkScreen
 * @monitor_num: the monitor number
 * @dest: (out) (allow-none): a #GdkRectangle to be filled with
 *     the monitor geometry
 *
 * Retrieves the #GdkRectangle representing the size and position of
 * the individual monitor within the entire screen area.
 *
 * Monitor numbers start at 0. To obtain the number of monitors of
 * @screen, use gdk_screen_get_n_monitors().
 *
 * Note that the size of the entire screen area can be retrieved via
 * gdk_screen_get_width() and gdk_screen_get_height().
 *
 * Since: 2.2
 */
void
gdk_screen_get_monitor_geometry (GdkScreen    *screen,
				 gint          monitor_num,
				 GdkRectangle *dest)
{
  g_return_if_fail (GDK_IS_SCREEN (screen));
  g_return_if_fail (monitor_num >= 0);
  g_return_if_fail (monitor_num < gdk_screen_get_n_monitors (screen));

  GDK_SCREEN_GET_CLASS(screen)->get_monitor_geometry (screen, monitor_num, dest);
}

/**
 * gdk_screen_get_monitor_workarea:
 * @screen: a #GdkScreen
 * @monitor_num: the monitor number
 * @dest: (out) (allow-none): a #GdkRectangle to be filled with
 *     the monitor workarea
 *
 * Retrieves the #GdkRectangle representing the size and position of
 * the "work area" on a monitor within the entire screen area.
 *
 * The work area should be considered when positioning menus and
 * similar popups, to avoid placing them below panels, docks or other
 * desktop components.
 *
 * Monitor numbers start at 0. To obtain the number of monitors of
 * @screen, use gdk_screen_get_n_monitors().
 *
 * Since: 3.4
 */
void
gdk_screen_get_monitor_workarea (GdkScreen    *screen,
                                 gint          monitor_num,
                                 GdkRectangle *dest)
{
  g_return_if_fail (GDK_IS_SCREEN (screen));
  g_return_if_fail (monitor_num >= 0);
  g_return_if_fail (monitor_num < gdk_screen_get_n_monitors (screen));

  GDK_SCREEN_GET_CLASS (screen)->get_monitor_workarea (screen, monitor_num, dest);
}

/**
 * gdk_screen_list_visuals:
 * @screen: the relevant #GdkScreen.
 *
 * 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.
 *
 * Return value: (transfer container) (element-type GdkVisual):
 *     a list of visuals; the list must be freed, but not its contents
 *
 * Since: 2.2
 **/
GList *
gdk_screen_list_visuals (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), NULL);

  return GDK_SCREEN_GET_CLASS (screen)->list_visuals (screen);
}

/**
 * gdk_screen_get_system_visual:
 * @screen: a #GdkScreen.
 *
 * 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.
 *
 * Return value: (transfer none): the system visual
 *
 * Since: 2.2
 **/
GdkVisual *
gdk_screen_get_system_visual (GdkScreen * screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), NULL);

  return GDK_SCREEN_GET_CLASS (screen)->get_system_visual (screen);
}

/**
 * gdk_screen_get_rgba_visual:
 * @screen: a #GdkScreen
 *
 * Gets a visual to use for creating windows 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().
 *
 * Return value: (transfer none): a visual to use for windows with an
 *     alpha channel or %NULL if the capability is not available.
 *
 * Since: 2.8
 **/
GdkVisual *
gdk_screen_get_rgba_visual (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), NULL);

  return GDK_SCREEN_GET_CLASS (screen)->get_rgba_visual (screen);
}

/**
 * gdk_screen_is_composited:
 * @screen: a #GdkScreen
 *
 * 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.
 *
 * Return value: Whether windows with RGBA visuals can reasonably be
 * expected to have their alpha channels drawn correctly on the screen.
 *
 * Since: 2.10
 **/
gboolean
gdk_screen_is_composited (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), FALSE);

  return GDK_SCREEN_GET_CLASS (screen)->is_composited (screen);
}

/**
 * gdk_screen_make_display_name:
 * @screen: a #GdkScreen
 *
 * Determines the name to pass to gdk_display_open() to get
 * a #GdkDisplay with this screen as the default screen.
 *
 * Return value: a newly allocated string, free with g_free()
 *
 * Since: 2.2
 **/
gchar *
gdk_screen_make_display_name (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), NULL);

  return GDK_SCREEN_GET_CLASS (screen)->make_display_name (screen);
}

/**
 * gdk_screen_get_active_window:
 * @screen: a #GdkScreen
 *
 * 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 <ulink
 * url="http://www.freedesktop.org/Standards/wm-spec">Extended Window
 * Manager Hints</ulink>. 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.
 *
 * Return value: (transfer full): the currently active window, or %NULL.
 *
 * Since: 2.10
 **/
GdkWindow *
gdk_screen_get_active_window (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), NULL);

  return GDK_SCREEN_GET_CLASS (screen)->get_active_window (screen);
}

/**
 * gdk_screen_get_window_stack:
 * @screen: a #GdkScreen
 *
 * Returns a #GList of #GdkWindow<!-- -->s 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 <ulink
 * url="http://www.freedesktop.org/Standards/wm-spec">Extended Window
 * Manager Hints</ulink>. 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.
 *
 * Return value: (transfer full) (element-type GdkWindow):
 *     a list of #GdkWindow<!-- -->s for the current window stack,
 *               or %NULL.
 *
 * Since: 2.10
 **/
GList *
gdk_screen_get_window_stack (GdkScreen *screen)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), NULL);

  return GDK_SCREEN_GET_CLASS (screen)->get_window_stack (screen);
}

/**
 * gdk_screen_get_setting:
 * @screen: the #GdkScreen where the setting is located
 * @name: the name of the setting
 * @value: location to store the value of the setting
 *
 * 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.
 *
 * Returns: %TRUE if the setting existed and a value was stored
 *   in @value, %FALSE otherwise.
 *
 * Since: 2.2
 **/
gboolean
gdk_screen_get_setting (GdkScreen   *screen,
			const gchar *name,
			GValue      *value)
{
  g_return_val_if_fail (GDK_IS_SCREEN (screen), FALSE);
  g_return_val_if_fail (name != NULL, FALSE);
  g_return_val_if_fail (value != NULL, FALSE);

  return GDK_SCREEN_GET_CLASS (screen)->get_setting (screen, name, value);
}

/**
 * gdk_screen_get_monitor_scale_factor:
 * @screen: screen to get scale factor for
 * @monitor_num: number of the monitor, between 0 and gdk_screen_get_n_monitors (screen)
 *
 * Returns the internal scale factor that maps from monitor coordiantes
 * to the actual device pixels. On traditional systems this is 1, but
 * on very high density outputs this can be a higher value (often 2).
 *
 * This can be used if you want to create pixel based data for a
 * particula monitor, but most of the time you're drawing to a window
 * where it is better to use gdk_window_get_scale_factor() instead.
 *
 * Since: 3.10
 * Return value: the scale factor
 */
gint
gdk_screen_get_monitor_scale_factor (GdkScreen *screen,
                                     gint       monitor_num)
{
  GdkScreenClass *screen_class;

  g_return_val_if_fail (GDK_IS_SCREEN (screen), 1);
  g_return_val_if_fail (monitor_num >= 0, 1);
  g_return_val_if_fail (monitor_num < gdk_screen_get_n_monitors (screen), 1);

  screen_class = GDK_SCREEN_GET_CLASS (screen);

  if (screen_class->get_monitor_scale_factor)
    return screen_class->get_monitor_scale_factor (screen, monitor_num);

  return 1;
}