GI.Gst.Interfaces.ChildProxy

This interface abstracts handling of property sets for elements with children. Imagine elements such as mixers or polyphonic generators. They all have multiple Pad or some kind of voice objects. Another use case are container elements like Bin. 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 ChildProxy interface.

Exported types

newtype ChildProxy

Constructors

ChildProxy (ManagedPtr ChildProxy)

Instances

GObject ChildProxy

Methods

gobjectType :: ChildProxy -> IO GType

IsObject ChildProxy

IsChildProxy ChildProxy

noChildProxy :: Maybe ChildProxy

class GObject o => IsChildProxy o

Instances

(GObject a, UnknownAncestorError Constraint ChildProxy a) => IsChildProxy a

IsChildProxy Bin

IsChildProxy ChildProxy

IsChildProxy Pipeline

toChildProxy :: (MonadIO m, IsChildProxy o) => o -> m ChildProxy

Methods

childAdded

childProxyChildAdded

Arguments

:: (HasCallStack, MonadIO m, IsChildProxy a, IsObject b)

=> a

parent: the parent object

-> b

child: the newly added child

-> Text

name: the name of the new child

-> m ()

Emits the "child-added" signal.

childRemoved

childProxyChildRemoved

Arguments

:: (HasCallStack, MonadIO m, IsChildProxy a, IsObject b)

=> a

parent: the parent object

-> b

child: the removed child

-> Text

name: the name of the old child

-> m ()

Emits the "child-removed" signal.

getChildByIndex

childProxyGetChildByIndex

Arguments

:: (HasCallStack, MonadIO m, IsChildProxy a)

=> a

parent: the parent object to get the child from

-> Word32

index: the child's position in the child list

-> m (Maybe Object)

Returns: the child object or Nothing if not found (index too high). Unref after usage.

MT safe.

Fetches a child by its number.

getChildByName

childProxyGetChildByName

Arguments

:: (HasCallStack, MonadIO m, IsChildProxy a)

=> a

parent: the parent object to get the child from

-> Text

name: the child's name

-> m (Maybe Object)

Returns: the child object or Nothing if not found. Unref after usage.

MT safe.

Looks up a child element by the given name.

This virtual method has a default implementation that uses Object together with objectGetName. If the interface is to be used with GObjects, this methods needs to be overridden.

getChildrenCount

childProxyGetChildrenCount

Arguments

:: (HasCallStack, MonadIO m, IsChildProxy a)

=> a

parent: the parent object

-> m Word32

Returns: the number of child objects

MT safe.

Gets the number of child objects this parent contains.

getProperty

childProxyGetProperty

Arguments

:: (HasCallStack, MonadIO m, IsChildProxy a)

=> a

object: object to query

-> Text

name: name of the property

-> m GValue

Gets a single property using the GstChildProxy mechanism. You are responsible for freeing it by calling valueUnset

lookup

childProxyLookup

Arguments

:: (HasCallStack, MonadIO m, IsChildProxy a)

=> a

object: child proxy object to lookup the property in

-> Text

name: name of the property to look up

-> m (Bool, Object, GParamSpec)

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. For plain GObjects target is the same as object.

Looks up which object and ParamSpec would be effected by the given name.

MT safe.

setProperty

childProxySetProperty

Arguments

:: (HasCallStack, MonadIO m, IsChildProxy a)

=> a

object: the parent object

-> Text

name: name of the property to set

-> GValue

value: new Value for the property

-> m ()

Sets a single property using the GstChildProxy mechanism.

Signals

childAdded

type C_ChildProxyChildAddedCallback = Ptr () -> Ptr Object -> CString -> Ptr () -> IO ()

type ChildProxyChildAddedCallback = Object -> Text -> IO ()

afterChildProxyChildAdded :: (IsChildProxy a, MonadIO m) => a -> ChildProxyChildAddedCallback -> m SignalHandlerId

genClosure_ChildProxyChildAdded :: ChildProxyChildAddedCallback -> IO Closure

mk_ChildProxyChildAddedCallback :: C_ChildProxyChildAddedCallback -> IO (FunPtr C_ChildProxyChildAddedCallback)

noChildProxyChildAddedCallback :: Maybe ChildProxyChildAddedCallback

onChildProxyChildAdded :: (IsChildProxy a, MonadIO m) => a -> ChildProxyChildAddedCallback -> m SignalHandlerId

wrap_ChildProxyChildAddedCallback :: ChildProxyChildAddedCallback -> Ptr () -> Ptr Object -> CString -> Ptr () -> IO ()

childRemoved

type C_ChildProxyChildRemovedCallback = Ptr () -> Ptr Object -> CString -> Ptr () -> IO ()

type ChildProxyChildRemovedCallback = Object -> Text -> IO ()

afterChildProxyChildRemoved :: (IsChildProxy a, MonadIO m) => a -> ChildProxyChildRemovedCallback -> m SignalHandlerId

genClosure_ChildProxyChildRemoved :: ChildProxyChildRemovedCallback -> IO Closure

mk_ChildProxyChildRemovedCallback :: C_ChildProxyChildRemovedCallback -> IO (FunPtr C_ChildProxyChildRemovedCallback)

noChildProxyChildRemovedCallback :: Maybe ChildProxyChildRemovedCallback

onChildProxyChildRemoved :: (IsChildProxy a, MonadIO m) => a -> ChildProxyChildRemovedCallback -> m SignalHandlerId

wrap_ChildProxyChildRemovedCallback :: ChildProxyChildRemovedCallback -> Ptr () -> Ptr Object -> CString -> Ptr () -> IO ()