Struct gdk4::DisplayManager

source ·
#[repr(transparent)]
pub struct DisplayManager { /* private fields */ }
Expand description

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

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

The GDK library can be built with support for multiple backends. The DisplayManager 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 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:

⚠️ The following code is in c ⚠️

#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");

Implementations§

Gets the default Display.

Returns

a Display

List all currently open displays.

Returns

a newly allocated GSList of Display objects

Opens a display.

name

the name of the display to open

Returns

a Display, or None if the display could not be opened

Sets @display as the default display.

display

a Display

Gets the singleton DisplayManager 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 set_allowed_backends() to limit what backends will be used.

Returns

The global DisplayManager singleton

Emitted when a display is opened.

display

the opened display

Trait Implementations§

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