|
|
|
GStreamer 0.10 Core Reference Manual | |
|---|---|---|---|---|
#include <gst/gst.h>
GstChildProxy;
GstChildProxyInterface;
guint gst_child_proxy_get_children_count (GstChildProxy *parent);
GstObject* gst_child_proxy_get_child_by_name (GstChildProxy *parent,
const gchar *name);
GstObject* gst_child_proxy_get_child_by_index (GstChildProxy *parent,
guint index);
gboolean gst_child_proxy_lookup (GstObject *object,
const gchar *name,
GstObject **target,
GParamSpec **pspec);
void gst_child_proxy_get_property (GstObject *object,
const gchar *name,
GValue *value);
void gst_child_proxy_get_valist (GstObject *object,
const gchar *first_property_name,
va_list var_args);
void gst_child_proxy_get (GstObject *object,
const gchar *first_property_name,
...);
void gst_child_proxy_set_property (GstObject *object,
const gchar *name,
const GValue *value);
void gst_child_proxy_set_valist (GstObject *object,
const gchar *first_property_name,
va_list var_args);
void gst_child_proxy_set (GstObject *object,
const gchar *first_property_name,
...);
void gst_child_proxy_child_added (GstObject *object,
GstObject *child);
void gst_child_proxy_child_removed (GstObject *object,
GstObject *child);
This interface abstracts handling of property sets for elements with children. Imagine elements such as mixers or polyphonic generators. They all have multiple GstPad or some kind of voice objects. Another use case are container elements like GstBin. The element implementing the interface acts as a parent for those child objects.
By implementing this interface the child properties can be accessed from the
parent element by using gst_child_proxy_get() and gst_child_proxy_set().
Property names are written as "child-name::property-name". The whole naming scheme is recursive. Thus "child1::child2::property" is valid too, if "child1" and "child2" implement the GstChildProxy interface.
typedef struct {
GTypeInterface parent;
/* methods */
GstObject *(*get_child_by_index) (GstChildProxy * parent, guint index);
guint (*get_children_count) (GstChildProxy * parent);
} GstChildProxyInterface;
GstChildProxy interface.
GTypeInterface parent; |
parent interface type. |
get_child_by_index () |
virtual method to fetch the child |
get_children_count () |
virtual method to get the children count |
guint gst_child_proxy_get_children_count (GstChildProxy *parent);
Gets the number of child objects this parent contains.
parent : |
the parent object |
| Returns : | the number of child objects MT safe. |
GstObject* gst_child_proxy_get_child_by_name (GstChildProxy *parent, const gchar *name);
Looks up a child element by the given name.
Implementors can use GstObject together with gst_object_get_name()
parent : |
the parent object to get the child from |
name : |
the childs name |
| Returns : | the child object or NULL if not found. Unref after usage.
MT safe.
|
GstObject* gst_child_proxy_get_child_by_index (GstChildProxy *parent, guint index);
Fetches a child by its number.
parent : |
the parent object to get the child from |
index : |
the childs position in the child list |
| Returns : | the child object or NULL if not found (index too high). Unref
after usage.
MT safe.
|
gboolean gst_child_proxy_lookup (GstObject *object, const gchar *name, GstObject **target, GParamSpec **pspec);
Looks up which object and GParamSpec would be effected by the given name.
object : |
object to lookup the property in |
name : |
name of the property to look up |
target : |
pointer to a GstObject that takes the real object to set property on |
pspec : |
pointer to take the GParamSpec describing the property |
| Returns : | TRUE if target and pspec could be found. FALSE otherwise. In that
case the values for pspec and target are not modified. Unref target after
usage.
MT safe.
|
void gst_child_proxy_get_property (GstObject *object, const gchar *name, GValue *value);
Gets a single property using the GstChildProxy mechanism.
You are responsible for for freeing it by calling g_value_unset()
object : |
object to query |
name : |
name of the property |
value : |
a GValue that should take the result. |
void gst_child_proxy_get_valist (GstObject *object, const gchar *first_property_name, va_list var_args);
Gets properties of the parent object and its children.
object : |
the object to query |
first_property_name : |
name of the first property to get |
var_args : |
return location for the first property, followed optionally by more name/return location pairs, followed by NULL |
void gst_child_proxy_get (GstObject *object, const gchar *first_property_name, ...);
Gets properties of the parent object and its children.
object : |
the parent object |
first_property_name : |
name of the first property to get |
... : |
return location for the first property, followed optionally by more name/return location pairs, followed by NULL |
void gst_child_proxy_set_property (GstObject *object, const gchar *name, const GValue *value);
Sets a single property using the GstChildProxy mechanism.
object : |
the parent object |
name : |
name of the property to set |
value : |
new GValue for the property |
void gst_child_proxy_set_valist (GstObject *object, const gchar *first_property_name, va_list var_args);
Sets properties of the parent object and its children.
object : |
the parent object |
first_property_name : |
name of the first property to set |
var_args : |
value for the first property, followed optionally by more name/value pairs, followed by NULL |
void gst_child_proxy_set (GstObject *object, const gchar *first_property_name, ...);
Sets properties of the parent object and its children.
object : |
the parent object |
first_property_name : |
name of the first property to set |
... : |
value for the first property, followed optionally by more name/value pairs, followed by NULL |
void gst_child_proxy_child_added (GstObject *object, GstObject *child);
Emits the "child-added" signal.
object : |
the parent object |
child : |
the newly added child |
"child-added" signalvoid user_function (GstChildProxy *child_proxy, GObject *object, gpointer user_data) : Run First
Will be emitted after the object was added to the child_proxy.
child_proxy : |
the GstChildProxy |
object : |
the GObject that was added |
user_data : |
user data set when the signal handler was connected. |
"child-removed" signalvoid user_function (GstChildProxy *child_proxy, GObject *object, gpointer user_data) : Run First
Will be emitted after the object was removed from the child_proxy.
child_proxy : |
the GstChildProxy |
object : |
the GObject that was removed |
user_data : |
user data set when the signal handler was connected. |