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ClutterBackend

ClutterBackend — Backend abstraction

Synopsis

                    ClutterBackend;
ClutterBackend *    clutter_get_default_backend         (void);
void                clutter_backend_set_resolution      (ClutterBackend *backend,
                                                         gdouble dpi);
gdouble             clutter_backend_get_resolution      (ClutterBackend *backend);
void                clutter_backend_set_double_click_time
                                                        (ClutterBackend *backend,
                                                         guint msec);
guint               clutter_backend_get_double_click_time
                                                        (ClutterBackend *backend);
void                clutter_backend_set_double_click_distance
                                                        (ClutterBackend *backend,
                                                         guint distance);
guint               clutter_backend_get_double_click_distance
                                                        (ClutterBackend *backend);
void                clutter_backend_set_font_options    (ClutterBackend *backend,
                                                         const cairo_font_options_t *options);
const cairo_font_options_t * clutter_backend_get_font_options
                                                        (ClutterBackend *backend);
void                clutter_backend_set_font_name       (ClutterBackend *backend,
                                                         const gchar *font_name);
const gchar *       clutter_backend_get_font_name       (ClutterBackend *backend);
CoglContext *       clutter_backend_get_cogl_context    (ClutterBackend *backend);

gboolean            clutter_check_windowing_backend     (const char *backend_type);

Object Hierarchy

  GObject
   +----ClutterBackend

Signals

  "font-changed"                                   : Run First
  "resolution-changed"                             : Run First
  "settings-changed"                               : Run First

Description

Clutter can be compiled against different backends. Each backend has to implement a set of functions, in order to be used by Clutter.

ClutterBackend is the base class abstracting the various implementation; it provides a basic API to query the backend for generic information and settings.

ClutterBackend is available since Clutter 0.4

Details

ClutterBackend

typedef struct _ClutterBackend ClutterBackend;

ClutterBackend is an opaque structure whose members cannot be directly accessed.

Since 0.4

clutter_get_default_backend ()

ClutterBackend *    clutter_get_default_backend         (void);

Retrieves the default ClutterBackend used by Clutter. The ClutterBackend holds backend-specific configuration options.

Returns :

 the default backend. You should not ref or unref the returned object. Applications should rarely need to use this. [transfer none]

Since 0.4

clutter_backend_set_resolution ()

void                clutter_backend_set_resolution      (ClutterBackend *backend,
                                                         gdouble dpi);

Warning

clutter_backend_set_resolution has been deprecated since version 1.4 and should not be used in newly-written code. Use "font-dpi" instead

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).

Applications should never need to call this function.

backend :

 a ClutterBackend

dpi :

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

Since 0.4

clutter_backend_get_resolution ()

gdouble             clutter_backend_get_resolution      (ClutterBackend *backend);

Gets the resolution for font handling on the screen.

The resolution is a scale factor between points specified in a PangoFontDescription and cairo units. The default value is 96.0, meaning that a 10 point font will be 13 units high (10 * 96. / 72. = 13.3).

Clutter will set the resolution using the current backend when initializing; the resolution is also stored in the "font-dpi" property.

backend :

 a ClutterBackend

Returns :

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

Since 0.4

clutter_backend_set_double_click_time ()

void                clutter_backend_set_double_click_time
                                                        (ClutterBackend *backend,
                                                         guint msec);

Warning

clutter_backend_set_double_click_time has been deprecated since version 1.4 and should not be used in newly-written code. Use "double-click-time" instead

Sets the maximum time between two button press events, used to verify whether it's a double click event or not.

backend :

 a ClutterBackend

msec :

 milliseconds between two button press events

Since 0.4

clutter_backend_get_double_click_time ()

guint               clutter_backend_get_double_click_time
                                                        (ClutterBackend *backend);

Warning

clutter_backend_get_double_click_time has been deprecated since version 1.4 and should not be used in newly-written code. Use "double-click-time" instead

Gets the maximum time between two button press events, as set by clutter_backend_set_double_click_time().

backend :

 a ClutterBackend

Returns :

 a time in milliseconds

Since 0.4

clutter_backend_set_double_click_distance ()

void                clutter_backend_set_double_click_distance
                                                        (ClutterBackend *backend,
                                                         guint distance);

Warning

clutter_backend_set_double_click_distance has been deprecated since version 1.4 and should not be used in newly-written code. Use "double-click-distance" instead

Sets the maximum distance used to verify a double click event.

backend :

 a ClutterBackend

distance :

 a distance, in pixels

Since 0.4

clutter_backend_get_double_click_distance ()

guint               clutter_backend_get_double_click_distance
                                                        (ClutterBackend *backend);

Warning

clutter_backend_get_double_click_distance has been deprecated since version 1.4 and should not be used in newly-written code. Use "double-click-distance" instead

Retrieves the distance used to verify a double click event

backend :

 a ClutterBackend

Returns :

 a distance, in pixels.

Since 0.4

clutter_backend_set_font_options ()

void                clutter_backend_set_font_options    (ClutterBackend *backend,
                                                         const cairo_font_options_t *options);

Sets the new font options for backend. The ClutterBackend will copy the cairo_font_options_t.

If options is NULL, the first following call to clutter_backend_get_font_options() will return the default font options for backend.

This function is intended for actors creating a Pango layout using the PangoCairo API.

backend :

 a ClutterBackend

options :

 Cairo font options for the backend, or NULL

Since 0.8

clutter_backend_get_font_options ()

const cairo_font_options_t * clutter_backend_get_font_options
                                                        (ClutterBackend *backend);

Retrieves the font options for backend.

backend :

 a ClutterBackend

Returns :

 the font options of the ClutterBackend. The returned cairo_font_options_t is owned by the backend and should not be modified or freed. [transfer none]

Since 0.8

clutter_backend_set_font_name ()

void                clutter_backend_set_font_name       (ClutterBackend *backend,
                                                         const gchar *font_name);

Warning

clutter_backend_set_font_name has been deprecated since version 1.4 and should not be used in newly-written code. Use "font-name" instead

Sets the default font to be used by Clutter. The font_name string must either be NULL, which means that the font name from the default ClutterBackend will be used; or be something that can be parsed by the pango_font_description_from_string() function.

backend :

 a ClutterBackend

font_name :

 the name of the font

Since 1.0

clutter_backend_get_font_name ()

const gchar *       clutter_backend_get_font_name       (ClutterBackend *backend);

Warning

clutter_backend_get_font_name has been deprecated since version 1.4 and should not be used in newly-written code. Use "font-name" instead

Retrieves the default font name as set by clutter_backend_set_font_name().

backend :

 a ClutterBackend

Returns :

 the font name for the backend. The returned string is owned by the ClutterBackend and should never be modified or freed

Since 1.0

clutter_backend_get_cogl_context ()

CoglContext *       clutter_backend_get_cogl_context    (ClutterBackend *backend);

Retrieves the CoglContext associated with the given clutter backend. A CoglContext is required when using some of the experimental 2.0 Cogl API.

Note

Since CoglContext is itself experimental API this API should be considered experimental too.

Note

This API is not yet supported on OSX because OSX still uses the stub Cogl winsys and the Clutter backend doesn't explicitly create a CoglContext.

backend :

 a ClutterBackend

Returns :

 The CoglContext associated with backend.

Since 1.8

Stability Level: Unstable

clutter_check_windowing_backend ()

gboolean            clutter_check_windowing_backend     (const char *backend_type);

Checks the run-time name of the Clutter windowing system backend, using the symbolic macros like CLUTTER_WINDOWING_WIN32 or CLUTTER_WINDOWING_X11.

This function should be used in conjuction with the compile-time macros inside applications and libraries that are using the platform-specific windowing system API, to ensure that they are running on the correct windowing system; for instance: 

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#ifdef CLUTTER_WINDOWING_X11
  if (clutter_check_windowing_backend (CLUTTER_WINDOWING_X11))
    {
      /* it is safe to use the clutter_x11_* API */
    }
  else
#endif
#ifdef CLUTTER_WINDOWING_WIN32
  if (clutter_check_windowing_backend (CLUTTER_WINDOWING_WIN32))
    {
      /* it is safe to use the clutter_win32_* API */
    }
  else
#endif
    g_error ("Unknown Clutter backend.");

backend_type :

 the name of the backend to check

Returns :

 TRUE if the current Clutter windowing system backend is the one checked, and FALSE otherwise

Since 1.10

Signal Details

The "font-changed" signal

void                user_function                      (ClutterBackend *backend,
                                                        gpointer        user_data)      : Run First

The ::font-changed signal is emitted each time the font options have been changed through ClutterSettings.

backend :

 the ClutterBackend that emitted the signal

user_data :

 user data set when the signal handler was connected.

Since 1.0

The "resolution-changed" signal

void                user_function                      (ClutterBackend *backend,
                                                        gpointer        user_data)      : Run First

The ::resolution-changed signal is emitted each time the font resolutions has been changed through ClutterSettings.

backend :

 the ClutterBackend that emitted the signal

user_data :

 user data set when the signal handler was connected.

Since 1.0

The "settings-changed" signal

void                user_function                      (ClutterBackend *backend,
                                                        gpointer        user_data)      : Run First

The ::settings-changed signal is emitted each time the ClutterSettings properties have been changed.

backend :

 the ClutterBackend that emitted the signal

user_data :

 user data set when the signal handler was connected.

Since 1.4

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