Navigation

The Navigation interface is used for creating and injecting navigation related events such as mouse button presses, cursor motion and key presses. The associated library also provides methods for parsing received events, and for sending and receiving navigation related bus events. One main usecase is DVD menu navigation.

The main parts of the API are:

The GstNavigation interface, implemented by elements which provide an application with the ability to create and inject navigation events into the pipeline.
GstNavigation event handling API. GstNavigation events are created in response to calls on a GstNavigation interface implementation, and sent in the pipeline. Upstream elements can use the navigation event API functions to parse the contents of received messages.
GstNavigation message handling API. GstNavigation messages may be sent on the message bus to inform applications of navigation related changes in the pipeline, such as the mouse moving over a clickable region, or the set of available angles changing.

The GstNavigation message functions provide functions for creating and parsing custom bus messages for signaling GstNavigation changes.

interface Navigation {

static bool eventGetCoordinates(gst.event.Event event, double x, double y);

static gstvideo.types.NavigationEventType eventGetType(gst.event.Event event);

static gst.event.Event eventNewCommand(gstvideo.types.NavigationCommand command);

static gst.event.Event eventNewKeyPress(string key, gstvideo.types.NavigationModifierType state);

static gst.event.Event eventNewKeyRelease(string key, gstvideo.types.NavigationModifierType state);

static gst.event.Event eventNewMouseButtonPress(int button, double x, double y, gstvideo.types.NavigationModifierType state);

static gst.event.Event eventNewMouseButtonRelease(int button, double x, double y, gstvideo.types.NavigationModifierType state);

static gst.event.Event eventNewMouseMove(double x, double y, gstvideo.types.NavigationModifierType state);

static gst.event.Event eventNewMouseScroll(double x, double y, double deltaX, double deltaY, gstvideo.types.NavigationModifierType state);

static gst.event.Event eventNewTouchCancel(gstvideo.types.NavigationModifierType state);

static gst.event.Event eventNewTouchDown(uint identifier, double x, double y, double pressure, gstvideo.types.NavigationModifierType state);

static gst.event.Event eventNewTouchFrame(gstvideo.types.NavigationModifierType state);

static gst.event.Event eventNewTouchMotion(uint identifier, double x, double y, double pressure, gstvideo.types.NavigationModifierType state);

static gst.event.Event eventNewTouchUp(uint identifier, double x, double y, gstvideo.types.NavigationModifierType state);

static bool eventParseCommand(gst.event.Event event, gstvideo.types.NavigationCommand command);

static bool eventParseKeyEvent(gst.event.Event event, string key);

static bool eventParseModifierState(gst.event.Event event, gstvideo.types.NavigationModifierType state);

static bool eventParseMouseButtonEvent(gst.event.Event event, int button, double x, double y);

static bool eventParseMouseMoveEvent(gst.event.Event event, double x, double y);

static bool eventParseMouseScrollEvent(gst.event.Event event, double x, double y, double deltaX, double deltaY);

static bool eventParseTouchEvent(gst.event.Event event, uint identifier, double x, double y, double pressure);

static bool eventParseTouchUpEvent(gst.event.Event event, uint identifier, double x, double y);

static bool eventSetCoordinates(gst.event.Event event, double x, double y);

static gstvideo.types.NavigationMessageType messageGetType(gst.message.Message message);

static gst.message.Message messageNewAnglesChanged(gst.object.ObjectGst src, uint curAngle, uint nAngles);

static gst.message.Message messageNewCommandsChanged(gst.object.ObjectGst src);

static gst.message.Message messageNewEvent(gst.object.ObjectGst src, gst.event.Event event);

static gst.message.Message messageNewMouseOver(gst.object.ObjectGst src, bool active);

static bool messageParseAnglesChanged(gst.message.Message message, uint curAngle, uint nAngles);

static bool messageParseEvent(gst.message.Message message, gst.event.Event event);

static bool messageParseMouseOver(gst.message.Message message, bool active);

static gstvideo.types.NavigationQueryType queryGetType(gst.query.Query query);

static gst.query.Query queryNewAngles();

static gst.query.Query queryNewCommands();

static bool queryParseAngles(gst.query.Query query, uint curAngle, uint nAngles);

static bool queryParseCommandsLength(gst.query.Query query, uint nCmds);

static bool queryParseCommandsNth(gst.query.Query query, uint nth, gstvideo.types.NavigationCommand cmd);

static void querySetAngles(gst.query.Query query, uint curAngle, uint nAngles);

static void querySetCommandsv(gst.query.Query query, gstvideo.types.NavigationCommand[] cmds);

void sendCommand(gstvideo.types.NavigationCommand command);

void sendEvent(gst.structure.Structure structure);

void sendEventSimple(gst.event.Event event);

void sendKeyEvent(string event, string key);

void sendMouseEvent(string event, int button, double x, double y);

void sendMouseScrollEvent(double x, double y, double deltaX, double deltaY);

}

Members

Functions

sendCommand void sendCommand(gstvideo.types.NavigationCommand command): Sends the indicated command to the navigation interface.
sendEvent void sendEvent(gst.structure.Structure structure)
sendEventSimple void sendEventSimple(gst.event.Event event): Sends an event to the navigation interface.
sendKeyEvent void sendKeyEvent(string event, string key)
sendMouseEvent void sendMouseEvent(string event, int button, double x, double y): Sends a mouse event to the navigation interface. Mouse event coordinates are sent relative to the display space of the related output area. This is usually the size in pixels of the window associated with the element implementing the #GstNavigation interface.
sendMouseScrollEvent void sendMouseScrollEvent(double x, double y, double deltaX, double deltaY): Sends a mouse scroll event to the navigation interface. Mouse event coordinates are sent relative to the display space of the related output area. This is usually the size in pixels of the window associated with the element implementing the #GstNavigation interface.

Static functions

eventGetCoordinates bool eventGetCoordinates(gst.event.Event event, double x, double y): Try to retrieve x and y coordinates of a #GstNavigation event.
eventGetType gstvideo.types.NavigationEventType eventGetType(gst.event.Event event): Inspect a #GstEvent and return the #GstNavigationEventType of the event, or #GST_NAVIGATION_EVENT_INVALID if the event is not a #GstNavigation event.
eventNewCommand gst.event.Event eventNewCommand(gstvideo.types.NavigationCommand command): Create a new navigation event given navigation command..
eventNewKeyPress gst.event.Event eventNewKeyPress(string key, gstvideo.types.NavigationModifierType state): Create a new navigation event for the given key press.
eventNewKeyRelease gst.event.Event eventNewKeyRelease(string key, gstvideo.types.NavigationModifierType state): Create a new navigation event for the given key release.
eventNewMouseButtonPress gst.event.Event eventNewMouseButtonPress(int button, double x, double y, gstvideo.types.NavigationModifierType state): Create a new navigation event for the given key mouse button press.
eventNewMouseButtonRelease gst.event.Event eventNewMouseButtonRelease(int button, double x, double y, gstvideo.types.NavigationModifierType state): Create a new navigation event for the given key mouse button release.
eventNewMouseMove gst.event.Event eventNewMouseMove(double x, double y, gstvideo.types.NavigationModifierType state): Create a new navigation event for the new mouse location.
eventNewMouseScroll gst.event.Event eventNewMouseScroll(double x, double y, double deltaX, double deltaY, gstvideo.types.NavigationModifierType state): Create a new navigation event for the mouse scroll.
eventNewTouchCancel gst.event.Event eventNewTouchCancel(gstvideo.types.NavigationModifierType state): Create a new navigation event signalling that all currently active touch points are cancelled and should be discarded. For example, under Wayland this event might be sent when a swipe passes the threshold to be recognized as a gesture by the compositor.
eventNewTouchDown gst.event.Event eventNewTouchDown(uint identifier, double x, double y, double pressure, gstvideo.types.NavigationModifierType state): Create a new navigation event for an added touch point.
eventNewTouchFrame gst.event.Event eventNewTouchFrame(gstvideo.types.NavigationModifierType state): Create a new navigation event signalling the end of a touch frame. Touch frames signal that all previous down, motion and up events not followed by another touch frame event already should be considered simultaneous.
eventNewTouchMotion gst.event.Event eventNewTouchMotion(uint identifier, double x, double y, double pressure, gstvideo.types.NavigationModifierType state): Create a new navigation event for a moved touch point.
eventNewTouchUp gst.event.Event eventNewTouchUp(uint identifier, double x, double y, gstvideo.types.NavigationModifierType state): Create a new navigation event for a removed touch point.
eventParseCommand bool eventParseCommand(gst.event.Event event, gstvideo.types.NavigationCommand command): Inspect a #GstNavigation command event and retrieve the enum value of the associated command.
eventParseKeyEvent bool eventParseKeyEvent(gst.event.Event event, string key): Note: Modifier keys (as defined in #GstNavigationModifierType) press and release events are generated even if those states are present on all other related events
eventParseModifierState bool eventParseModifierState(gst.event.Event event, gstvideo.types.NavigationModifierType state)
eventParseMouseButtonEvent bool eventParseMouseButtonEvent(gst.event.Event event, int button, double x, double y): Retrieve the details of either a #GstNavigation mouse button press event or a mouse button release event. Determine which type the event is using gstvideo.navigation.Navigation.eventGetType to retrieve the #GstNavigationEventType.
eventParseMouseMoveEvent bool eventParseMouseMoveEvent(gst.event.Event event, double x, double y): Inspect a #GstNavigation mouse movement event and extract the coordinates of the event.
eventParseMouseScrollEvent bool eventParseMouseScrollEvent(gst.event.Event event, double x, double y, double deltaX, double deltaY): Inspect a #GstNavigation mouse scroll event and extract the coordinates of the event.
eventParseTouchEvent bool eventParseTouchEvent(gst.event.Event event, uint identifier, double x, double y, double pressure): Retrieve the details of a #GstNavigation touch-down or touch-motion event. Determine which type the event is using gstvideo.navigation.Navigation.eventGetType to retrieve the #GstNavigationEventType.
eventParseTouchUpEvent bool eventParseTouchUpEvent(gst.event.Event event, uint identifier, double x, double y): Retrieve the details of a #GstNavigation touch-up event.
eventSetCoordinates bool eventSetCoordinates(gst.event.Event event, double x, double y): Try to set x and y coordinates on a #GstNavigation event. The event must be writable.
messageGetType gstvideo.types.NavigationMessageType messageGetType(gst.message.Message message): Check a bus message to see if it is a #GstNavigation event, and return the #GstNavigationMessageType identifying the type of the message if so.
messageNewAnglesChanged gst.message.Message messageNewAnglesChanged(gst.object.ObjectGst src, uint curAngle, uint nAngles): Creates a new #GstNavigation message with type #GST_NAVIGATION_MESSAGE_ANGLES_CHANGED for notifying an application that the current angle, or current number of angles available in a multiangle video has changed.
messageNewCommandsChanged gst.message.Message messageNewCommandsChanged(gst.object.ObjectGst src): Creates a new #GstNavigation message with type #GST_NAVIGATION_MESSAGE_COMMANDS_CHANGED
messageNewEvent gst.message.Message messageNewEvent(gst.object.ObjectGst src, gst.event.Event event): Creates a new #GstNavigation message with type #GST_NAVIGATION_MESSAGE_EVENT.
messageNewMouseOver gst.message.Message messageNewMouseOver(gst.object.ObjectGst src, bool active): Creates a new #GstNavigation message with type #GST_NAVIGATION_MESSAGE_MOUSE_OVER.
messageParseAnglesChanged bool messageParseAnglesChanged(gst.message.Message message, uint curAngle, uint nAngles): Parse a #GstNavigation message of type GST_NAVIGATION_MESSAGE_ANGLES_CHANGED and extract the cur_angle and n_angles parameters.
messageParseEvent bool messageParseEvent(gst.message.Message message, gst.event.Event event): Parse a #GstNavigation message of type #GST_NAVIGATION_MESSAGE_EVENT and extract contained #GstEvent. The caller must unref the event when done with it.
messageParseMouseOver bool messageParseMouseOver(gst.message.Message message, bool active): Parse a #GstNavigation message of type #GST_NAVIGATION_MESSAGE_MOUSE_OVER and extract the active/inactive flag. If the mouse over event is marked active, it indicates that the mouse is over a clickable area.
queryGetType gstvideo.types.NavigationQueryType queryGetType(gst.query.Query query): Inspect a #GstQuery and return the #GstNavigationQueryType associated with it if it is a #GstNavigation query.
queryNewAngles gst.query.Query queryNewAngles(): Create a new #GstNavigation angles query. When executed, it will query the pipeline for the set of currently available angles, which may be greater than one in a multiangle video.
queryNewCommands gst.query.Query queryNewCommands(): Create a new #GstNavigation commands query. When executed, it will query the pipeline for the set of currently available commands.
queryParseAngles bool queryParseAngles(gst.query.Query query, uint curAngle, uint nAngles): Parse the current angle number in the #GstNavigation angles query into the #guint pointed to by the cur_angle variable, and the number of available angles into the #guint pointed to by the n_angles variable.
queryParseCommandsLength bool queryParseCommandsLength(gst.query.Query query, uint nCmds): Parse the number of commands in the #GstNavigation commands query.
queryParseCommandsNth bool queryParseCommandsNth(gst.query.Query query, uint nth, gstvideo.types.NavigationCommand cmd): Parse the #GstNavigation command query and retrieve the nth command from it into cmd. If the list contains less elements than nth, cmd will be set to #GST_NAVIGATION_COMMAND_INVALID.
querySetAngles void querySetAngles(gst.query.Query query, uint curAngle, uint nAngles): Set the #GstNavigation angles query result field in query.
querySetCommandsv void querySetCommandsv(gst.query.Query query, gstvideo.types.NavigationCommand[] cmds): Set the #GstNavigation command query result fields in query. The number of commands passed must be equal to n_commands.

gstvideo navigation interfaces

Navigation