Copyright	Will Thompson, Iñaki García Etxebarria and Jonas Platte
License	LGPL-2.1
Maintainer	Iñaki García Etxebarria (garetxe@gmail.com)
Safe Haskell	None
Language	Haskell2010

GI.Gst.Structs.Context

Contents

Exported types
Methods

Description

#GstContext is a container object used to store contexts like a device context, a display server connection and similar concepts that should be shared between multiple elements.

Applications can set a context on a complete pipeline by using gst_element_set_context(), which will then be propagated to all child elements. Elements can handle these in #GstElementClass.set_context() and merge them with the context information they already have.

When an element needs a context it will do the following actions in this order until one step succeeds: 1. Check if the element already has a context 2. Query downstream with GST_QUERY_CONTEXT for the context 3. Query upstream with GST_QUERY_CONTEXT for the context 4. Post a GST_MESSAGE_NEED_CONTEXT message on the bus with the required context types and afterwards check if a usable context was set now 5. Create a context by itself and post a GST_MESSAGE_HAVE_CONTEXT message on the bus.

Bins will catch GST_MESSAGE_NEED_CONTEXT messages and will set any previously known context on the element that asks for it if possible. Otherwise the application should provide one if it can.

Synopsis

Exported types

newtype Context Source

Constructors

Context (ForeignPtr Context)

Instances

BoxedObject Context Source
Methods boxedType :: Context -> IO GType
((~) * info (ResolveContextMethod t Context), MethodInfo * info Context p) => IsLabel t (Context -> p) Source
Methods fromLabel :: Proxy# Symbol t -> Context -> p
((~) * info (ResolveContextMethod t Context), MethodInfo * info Context p) => IsLabelProxy t (Context -> p) Source
Methods fromLabelProxy :: Proxy Symbol t -> Context -> p
((~) (TYPE Lifted) signature (m Structure), MonadIO m) => MethodInfo (TYPE Lifted) ContextWritableStructureMethodInfo Context signature Source
Methods overloadedMethod :: MethodProxy ContextWritableStructureMethodInfo Context -> signature -> s
((~) (TYPE Lifted) signature (m Bool), MonadIO m) => MethodInfo (TYPE Lifted) ContextIsPersistentMethodInfo Context signature Source
Methods overloadedMethod :: MethodProxy ContextIsPersistentMethodInfo Context -> signature -> s
((~) (TYPE Lifted) signature (Text -> m Bool), MonadIO m) => MethodInfo (TYPE Lifted) ContextHasContextTypeMethodInfo Context signature Source
Methods overloadedMethod :: MethodProxy ContextHasContextTypeMethodInfo Context -> signature -> s
((~) (TYPE Lifted) signature (m Structure), MonadIO m) => MethodInfo (TYPE Lifted) ContextGetStructureMethodInfo Context signature Source
Methods overloadedMethod :: MethodProxy ContextGetStructureMethodInfo Context -> signature -> s
((~) (TYPE Lifted) signature (m Text), MonadIO m) => MethodInfo (TYPE Lifted) ContextGetContextTypeMethodInfo Context signature Source
Methods overloadedMethod :: MethodProxy ContextGetContextTypeMethodInfo Context -> signature -> s

noContext :: Maybe Context Source

Methods

contextGetContextType

data ContextGetContextTypeMethodInfo Source

Instances

((~) (TYPE Lifted) signature (m Text), MonadIO m) => MethodInfo (TYPE Lifted) ContextGetContextTypeMethodInfo Context signature Source
Methods overloadedMethod :: MethodProxy ContextGetContextTypeMethodInfo Context -> signature -> s

contextGetContextType :: MonadIO m => Context -> m Text Source

contextGetStructure

data ContextGetStructureMethodInfo Source

Instances

((~) (TYPE Lifted) signature (m Structure), MonadIO m) => MethodInfo (TYPE Lifted) ContextGetStructureMethodInfo Context signature Source
Methods overloadedMethod :: MethodProxy ContextGetStructureMethodInfo Context -> signature -> s

contextGetStructure :: MonadIO m => Context -> m Structure Source

contextHasContextType

data ContextHasContextTypeMethodInfo Source

Instances

((~) (TYPE Lifted) signature (Text -> m Bool), MonadIO m) => MethodInfo (TYPE Lifted) ContextHasContextTypeMethodInfo Context signature Source
Methods overloadedMethod :: MethodProxy ContextHasContextTypeMethodInfo Context -> signature -> s

contextHasContextType :: MonadIO m => Context -> Text -> m Bool Source

contextIsPersistent

data ContextIsPersistentMethodInfo Source

Instances

((~) (TYPE Lifted) signature (m Bool), MonadIO m) => MethodInfo (TYPE Lifted) ContextIsPersistentMethodInfo Context signature Source
Methods overloadedMethod :: MethodProxy ContextIsPersistentMethodInfo Context -> signature -> s

contextIsPersistent :: MonadIO m => Context -> m Bool Source

contextNew

contextNew :: MonadIO m => Text -> Bool -> m Context Source

contextWritableStructure

data ContextWritableStructureMethodInfo Source

Instances

((~) (TYPE Lifted) signature (m Structure), MonadIO m) => MethodInfo (TYPE Lifted) ContextWritableStructureMethodInfo Context signature Source
Methods overloadedMethod :: MethodProxy ContextWritableStructureMethodInfo Context -> signature -> s

contextWritableStructure :: MonadIO m => Context -> m Structure Source