Class: Gdk::DisplayManager

Inherits:
Object
  • Object
show all
Defined in:
(unknown)

Overview

A singleton object that offers notification when displays appear or disappear.

You can use [funcGdk.DisplayManager.get] to obtain the GdkDisplayManager singleton, but that should be rarely necessary. Typically, initializing GTK opens a display that you can work with without ever accessing the GdkDisplayManager.

The GDK library can be built with support for multiple backends. The GdkDisplayManager object determines which backend is used at runtime.

In the rare case that you need to influence which of the backends is being used, you can use [funcGdk.set_allowed_backends]. Note that you need to call this function before initializing GTK.

Backend-specific code

When writing backend-specific code that is supposed to work with multiple GDK backends, you have to consider both compile time and runtime. At compile time, use the GDK_WINDOWING_X11, GDK_WINDOWING_WIN32 macros, etc. to find out which backends are present in the GDK library you are building your application against. At runtime, use type-check macros like GDK_IS_X11_DISPLAY() to find out which backend is in use:

#ifdef GDK_WINDOWING_X11
  if (GDK_IS_X11_DISPLAY (display))
    {
      // make X11-specific calls here
    }
  else
#endif
#ifdef GDK_WINDOWING_MACOS
  if (GDK_IS_MACOS_DISPLAY (display))
    {
      // make Quartz-specific calls here
    }
  else
#endif
  g_error ("Unsupported GDK backend");

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.get ⇒ Gdk::DisplayManager

Gets the singleton GdkDisplayManager object.

When called for the first time, this function consults the GDK_BACKEND environment variable to find out which of the supported GDK backends to use (in case GDK has been compiled with multiple backends).

Applications can use [funcset_allowed_backends] to limit what backends will be used.

Returns:

Instance Method Details

#default_display ⇒ Gdk::Display

The default display.

Returns:

#default_display=(default_display) ⇒ Gdk::Display

The default display.

Parameters:

Returns:

#list_displays ⇒ GLib::SList<Gdk::Display>

List all currently open displays.

Returns:

  • (GLib::SList<Gdk::Display>) —

    a newly allocated GSList of GdkDisplay objects

#open_display(name) ⇒ Gdk::Display

Opens a display.

Parameters:

  • name (String) —

    the name of the display to open

Returns:

  • (Gdk::Display) —

    a GdkDisplay, or nil if the display could not be opened