gstreamermm 0.10.10.1
Public Member Functions | Static Public Member Functions | Related Functions
Gst::XOverlay Class Reference

An interface for setting/getting a Window on elements supporting it. More...

Inheritance diagram for Gst::XOverlay:
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Collaboration diagram for Gst::XOverlay:
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List of all members.

Public Member Functions

virtual ~XOverlay ()
GstXOverlay* gobj ()
 Provides access to the underlying C GObject.
const GstXOverlay* gobj () const
 Provides access to the underlying C GObject.
void set_xwindow_id (gulong xwindow_id)
 This will call the video overlay's set_xwindow_id method.
void got_xwindow_id (gulong xwindow_id)
 This will post a "have-xwindow-id" element message on the bus.
void got_window_handle (guintptr xwindow_id)
 This will post a "have-xwindow-id" element message on the bus.
void set_window_handle (guintptr xwindow_handle)
 This will call the video overlay's set_window_handle method.
void prepare_xwindow_id ()
 This will post a "prepare-xwindow-id" element message on the bus to give applications an opportunity to call gst_x_overlay_set_xwindow_id() before a plugin creates its own window.
void expose ()
 Tell an overlay that it has been exposed.
void handle_events (bool handle_events)
 Tell an overlay that it should handle events from the window system.
bool set_render_rectangle (int x, int y, int width, int height)
 Configure a subregion as a video target within the window set by gst_x_overlay_set_window_handle().
virtual void set_xwindow_id_vfunc (gulong xwindow_id)
 Virtual method to configure the XWindow id.
virtual void expose_vfunc ()
 Virtual method to handle expose events.
virtual void handle_events_vfunc (bool handle_events)
 Virtual method to handle events.

Static Public Member Functions

static void add_interface (GType gtype_implementer)

Related Functions

(Note that these are not member functions.)

Glib::RefPtr< Gst::XOverlaywrap (GstXOverlay* object, bool take_copy=false)
 A Glib::wrap() method for this object.

Detailed Description

An interface for setting/getting a Window on elements supporting it.

The XOverlay interface is used for 2 main purposes :

Using the Window created by the video sink is probably the simplest scenario, in some cases, though, it might not be flexible enough for application developers if they need to catch events such as mouse moves and button clicks.

Setting a specific Window identifier on the video sink element is the most flexible solution but it has some issues. Indeed the application needs to set its Window identifier at the right time to avoid internal Window creation from the video sink element. To solve this issue a Message is posted on the bus to inform the application that it should set the Window identifier immediately. Here is an example on how to do that correctly:

 #include <gdk/gdkx.h>
 ...
 void PlayerWindow::on_bus_message_sync(
     const Glib::RefPtr<Gst::Message>& message)
 {
   // ignore anything but 'prepare-xwindow-id' element messages
   if(message->get_message_type() != Gst::MESSAGE_ELEMENT)
    return;

   if(!message->get_structure().has_name("prepare-xwindow-id"))
      return;

   Glib::RefPtr<Gst::Element> element =
       Glib::RefPtr<Gst::Element>::cast_dynamic(message->get_source());

   Glib::RefPtr< Gst::ElementInterfaced<Gst::XOverlay> > xoverlay =
       Gst::Interface::cast <Gst::XOverlay>(element);

   if(xoverlay)
   {
     const gulong xWindowId =
     GDK_WINDOW_XID(widget->get_window()->gobj());
     xoverlay->set_xwindow_id(xWindowId);
   }
 }
 ...
 int main (int argc, char *argv[])
 {
   ...
   // Get the bus from the pipeline:
   Glib::RefPtr<Gst::Bus> bus = pipeline->get_bus();
 
  // Enable synchronous message emission:
  bus->enable_sync_message_emission();

  // Connect to bus's synchronous message signal:
  bus->signal_sync_message().connect(
    sigc::mem_fun(*this, &PlayerWindow::on_bus_message_sync));
   ...
 }

Constructor & Destructor Documentation

virtual Gst::XOverlay::~XOverlay ( ) [virtual]

Member Function Documentation

static void Gst::XOverlay::add_interface ( GType  gtype_implementer) [static]
void Gst::XOverlay::expose ( )

Tell an overlay that it has been exposed.

This will redraw the current frame in the drawable even if the pipeline is PAUSED.

virtual void Gst::XOverlay::expose_vfunc ( ) [virtual]

Virtual method to handle expose events.

GstXOverlay* Gst::XOverlay::gobj ( ) [inline]

Provides access to the underlying C GObject.

Reimplemented from Glib::Interface.

Reimplemented in Gst::XImageSink, and Gst::XvImageSink.

const GstXOverlay* Gst::XOverlay::gobj ( ) const [inline]

Provides access to the underlying C GObject.

Reimplemented from Glib::Interface.

Reimplemented in Gst::XImageSink, and Gst::XvImageSink.

void Gst::XOverlay::got_window_handle ( guintptr  xwindow_id)

This will post a "have-xwindow-id" element message on the bus.

This function should only be used by video overlay plugin developers.

Parameters:
handleA platform-specific handle referencing the window.
void Gst::XOverlay::got_xwindow_id ( gulong  xwindow_id)

This will post a "have-xwindow-id" element message on the bus.

This function should only be used by video overlay plugin developers.

Deprecated: Use gst_x_overlay_got_window_handle() instead.

Parameters:
xwindow_idA X::ID referencing the XWindow.
void Gst::XOverlay::handle_events ( bool  handle_events)

Tell an overlay that it should handle events from the window system.

These events are forwared upstream as navigation events. In some window system, events are not propagated in the window hierarchy if a client is listening for them. This method allows you to disable events handling completely from the XOverlay.

Parameters:
handle_eventsA bool indicating if events should be handled or not.
virtual void Gst::XOverlay::handle_events_vfunc ( bool  handle_events) [virtual]

Virtual method to handle events.

void Gst::XOverlay::prepare_xwindow_id ( )

This will post a "prepare-xwindow-id" element message on the bus to give applications an opportunity to call gst_x_overlay_set_xwindow_id() before a plugin creates its own window.

This function should only be used by video overlay plugin developers.

bool Gst::XOverlay::set_render_rectangle ( int  x,
int  y,
int  width,
int  height 
)

Configure a subregion as a video target within the window set by gst_x_overlay_set_window_handle().

If this is not used or not supported the video will fill the area of the window set as the overlay to 100%. By specifying the rectangle, the video can be overlayed to a specific region of that window only. After setting the new rectangle one should call gst_x_overlay_expose() to force a redraw. To unset the region pass -1 for the width and height parameters.

This method is needed for non fullscreen video overlay in UI toolkits that do not support subwindows.

Parameters:
xThe horizontal offset of the render area inside the window.
yThe vertical offset of the render area inside the window.
widthThe width of the render area inside the window.
heightThe height of the render area inside the window.
Returns:
false if not supported by the sink.
void Gst::XOverlay::set_window_handle ( guintptr  xwindow_handle)

This will call the video overlay's set_window_handle method.

You should use this method to tell to a XOverlay to display video output to a specific XWindow. Passing 0 as the xwindow_id will tell the overlay to stop using that window and create an internal one.

Parameters:
xwindow_idA X::ID referencing the XWindow.
void Gst::XOverlay::set_xwindow_id ( gulong  xwindow_id)

This will call the video overlay's set_xwindow_id method.

You should use this method to tell to a XOverlay to display video output to a specific XWindow. Passing 0 as the xwindow_id will tell the overlay to stop using that window and create an internal one.

Deprecated: Use gst_x_overlay_set_window_handle() instead.

Parameters:
xwindow_idA X::ID referencing the XWindow.
virtual void Gst::XOverlay::set_xwindow_id_vfunc ( gulong  xwindow_id) [virtual]

Virtual method to configure the XWindow id.


Friends And Related Function Documentation

Glib::RefPtr< Gst::XOverlay > wrap ( GstXOverlay *  object,
bool  take_copy = false 
) [related]

A Glib::wrap() method for this object.

Parameters:
objectThe C instance.
take_copyFalse if the result should take ownership of the C instance. True if it should take a new copy or ref.
Returns:
A C++ instance that wraps this C instance.

The documentation for this class was generated from the following file: