Utilities

Utilities — Misc utility functions.

Synopsis

int                 clutter_util_next_p2                (int a);

ClutterTimeoutPool* clutter_timeout_pool_new            (gint priority);
guint               clutter_timeout_pool_add            (ClutterTimeoutPool *pool,
                                                         guint interval,
                                                         GSourceFunc func,
                                                         gpointer data,
                                                         GDestroyNotify notify);
void                clutter_timeout_pool_remove         (ClutterTimeoutPool *pool,
                                                         guint id);

guint               clutter_frame_source_add            (guint interval,
                                                         GSourceFunc func,
                                                         gpointer data);
guint               clutter_frame_source_add_full       (gint priority,
                                                         guint interval,
                                                         GSourceFunc func,
                                                         gpointer data,
                                                         GDestroyNotify notify);

Description

Various misc utilility functions.

Details

clutter_util_next_p2 ()

int                 clutter_util_next_p2                (int a);

Calculates the nearest power of two, greater than or equal to a.

a :

Value to get the next power

Returns :

The nearest power of two, greater or equal to a.

clutter_timeout_pool_new ()

ClutterTimeoutPool* clutter_timeout_pool_new            (gint priority);

Creates a new timeout pool source. A timeout pool should be used when multiple timeout functions, running at the same priority, are needed and the g_timeout_add() API might lead to starvation of the time slice of the main loop. A timeout pool allocates a single time slice of the main loop and runs every timeout function inside it. The timeout pool is always sorted, so that the extraction of the next timeout function is a constant time operation.

Inside Clutter, every ClutterTimeline share the same timeout pool, unless the CLUTTER_TIMELINE=no-pool environment variable is set.

ClutterTimeoutPool is part of the ClutterTimeline implementation and should not be used by application developers.

priority :

the priority of the timeout pool. Typically this will be G_PRIORITY_DEFAULT

Returns :

the newly created ClutterTimeoutPool. The created pool is owned by the GLib default context and will be automatically destroyed when the context is destroyed. It is possible to force the destruction of the timeout pool using g_source_destroy()

Since 0.4


clutter_timeout_pool_add ()

guint               clutter_timeout_pool_add            (ClutterTimeoutPool *pool,
                                                         guint interval,
                                                         GSourceFunc func,
                                                         gpointer data,
                                                         GDestroyNotify notify);

Sets a function to be called at regular intervals, and puts it inside the pool. The function is repeatedly called until it returns FALSE, at which point the timeout is automatically destroyed and the function won't be called again. If notify is not NULL, the notify function will be called. The first call to func will be at the end of interval.

Since version 0.8 this will try to compensate for delays. For example, if func takes half the interval time to execute then the function will be called again half the interval time after it finished. Before version 0.8 it would not fire until a full interval after the function completes so the delay between calls would be interval * 1.5. This function does not however try to invoke the function multiple times to catch up missing frames if func takes more than interval ms to execute.

pool :

a ClutterTimeoutPool

interval :

the time between calls to the function, in milliseconds

func :

function to call

data :

data to pass to the function, or NULL

notify :

function to call when the timeout is removed, or NULL

Returns :

the ID (greater than 0) of the timeout inside the pool. Use clutter_timeout_pool_remove() to stop the timeout.

Since 0.4


clutter_timeout_pool_remove ()

void                clutter_timeout_pool_remove         (ClutterTimeoutPool *pool,
                                                         guint id);

Removes a timeout function with id from the timeout pool. The id is the same returned when adding a function to the timeout pool with clutter_timeout_pool_add().

pool :

a ClutterTimeoutPool

id :

the id of the timeout to remove

Since 0.4


clutter_frame_source_add ()

guint               clutter_frame_source_add            (guint interval,
                                                         GSourceFunc func,
                                                         gpointer data);

Simple wrapper around clutter_frame_source_add_full().

interval :

the time between calls to the function, in milliseconds

func :

function to call

data :

data to pass to the function

Returns :

the ID (greater than 0) of the event source.

Since 0.8


clutter_frame_source_add_full ()

guint               clutter_frame_source_add_full       (gint priority,
                                                         guint interval,
                                                         GSourceFunc func,
                                                         gpointer data,
                                                         GDestroyNotify notify);

Sets a function to be called at regular intervals with the given priority. The function is called repeatedly until it returns FALSE, at which point the timeout is automatically destroyed and the function will not be called again. The notify function is called when the timeout is destroyed. The first call to the function will be at the end of the first interval.

This function is similar to g_timeout_add_full() except that it will try to compensate for delays. For example, if func takes half the interval time to execute then the function will be called again half the interval time after it finished. In contrast g_timeout_add_full() would not fire until a full interval after the function completes so the delay between calls would be interval * 1.5. This function does not however try to invoke the function multiple times to catch up missing frames if func takes more than interval ms to execute.

priority :

the priority of the frame source. Typically this will be in the range between G_PRIORITY_DEFAULT and G_PRIORITY_HIGH.

interval :

the time between calls to the function, in milliseconds

func :

function to call

data :

data to pass to the function

notify :

function to call when the timeout source is removed

Returns :

the ID (greater than 0) of the event source.

Since 0.8