/* GStreamer Video Overlay interface
* Copyright (C) 2003 Ronald Bultje <rbultje@ronald.bitfreak.net>
* Copyright (C) 2011 Tim-Philipp Müller <tim@centricular.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:gstvideooverlay
* @title: GstVideoOverlay
* @short_description: Interface for setting/getting a window system resource
* on elements supporting it to configure a window into which to render a
* video.
*
* The #GstVideoOverlay interface is used for 2 main purposes :
*
* * To get a grab on the Window where the video sink element is going to render.
* This is achieved by either being informed about the Window identifier that
* the video sink element generated, or by forcing the video sink element to use
* a specific Window identifier for rendering.
* * To force a redrawing of the latest video frame the video sink element
* displayed on the Window. Indeed if the #GstPipeline is in #GST_STATE_PAUSED
* state, moving the Window around will damage its content. Application
* developers will want to handle the Expose events themselves and force the
* video sink element to refresh the Window's content.
*
* 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 #GstMessage 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:
* |[
* static GstBusSyncReply
* create_window (GstBus * bus, GstMessage * message, GstPipeline * pipeline)
* {
* // ignore anything but 'prepare-window-handle' element messages
* if (!gst_is_video_overlay_prepare_window_handle_message (message))
* return GST_BUS_PASS;
*
* win = XCreateSimpleWindow (disp, root, 0, 0, 320, 240, 0, 0, 0);
*
* XSetWindowBackgroundPixmap (disp, win, None);
*
* XMapRaised (disp, win);
*
* XSync (disp, FALSE);
*
* gst_video_overlay_set_window_handle (GST_VIDEO_OVERLAY (GST_MESSAGE_SRC (message)),
* win);
*
* gst_message_unref (message);
*
* return GST_BUS_DROP;
* }
* ...
* int
* main (int argc, char **argv)
* {
* ...
* bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
* gst_bus_set_sync_handler (bus, (GstBusSyncHandler) create_window, pipeline,
NULL);
* ...
* }
* ]|
*
* ## Two basic usage scenarios
*
* There are two basic usage scenarios: in the simplest case, the application
* uses #playbin or #plasink or knows exactly what particular element is used
* for video output, which is usually the case when the application creates
* the videosink to use (e.g. #xvimagesink, #ximagesink, etc.) itself; in this
* case, the application can just create the videosink element, create and
* realize the window to render the video on and then
* call gst_video_overlay_set_window_handle() directly with the XID or native
* window handle, before starting up the pipeline.
* As #playbin and #playsink implement the video overlay interface and proxy
* it transparently to the actual video sink even if it is created later, this
* case also applies when using these elements.
*
* In the other and more common case, the application does not know in advance
* what GStreamer video sink element will be used for video output. This is
* usually the case when an element such as #autovideosink is used.
* In this case, the video sink element itself is created
* asynchronously from a GStreamer streaming thread some time after the
* pipeline has been started up. When that happens, however, the video sink
* will need to know right then whether to render onto an already existing
* application window or whether to create its own window. This is when it
* posts a prepare-window-handle message, and that is also why this message needs
* to be handled in a sync bus handler which will be called from the streaming
* thread directly (because the video sink will need an answer right then).
*
* As response to the prepare-window-handle element message in the bus sync
* handler, the application may use gst_video_overlay_set_window_handle() to tell
* the video sink to render onto an existing window surface. At this point the
* application should already have obtained the window handle / XID, so it
* just needs to set it. It is generally not advisable to call any GUI toolkit
* functions or window system functions from the streaming thread in which the
* prepare-window-handle message is handled, because most GUI toolkits and
* windowing systems are not thread-safe at all and a lot of care would be
* required to co-ordinate the toolkit and window system calls of the
* different threads (Gtk+ users please note: prior to Gtk+ 2.18
* GDK_WINDOW_XID() was just a simple structure access, so generally fine to do
* within the bus sync handler; this macro was changed to a function call in
* Gtk+ 2.18 and later, which is likely to cause problems when called from a
* sync handler; see below for a better approach without GDK_WINDOW_XID()
* used in the callback).
*
* ## GstVideoOverlay and Gtk+
*
* |[
* #include <gst/video/videooverlay.h>
* #include <gtk/gtk.h>
* #ifdef GDK_WINDOWING_X11
* #include <gdk/gdkx.h> // for GDK_WINDOW_XID
* #endif
* #ifdef GDK_WINDOWING_WIN32
* #include <gdk/gdkwin32.h> // for GDK_WINDOW_HWND
* #endif
* ...
* static guintptr video_window_handle = 0;
* ...
* static GstBusSyncReply
* bus_sync_handler (GstBus * bus, GstMessage * message, gpointer user_data)
* {
* // ignore anything but 'prepare-window-handle' element messages
* if (!gst_is_video_overlay_prepare_window_handle_message (message))
* return GST_BUS_PASS;
*
* if (video_window_handle != 0) {
* GstVideoOverlay *overlay;
*
* // GST_MESSAGE_SRC (message) will be the video sink element
* overlay = GST_VIDEO_OVERLAY (GST_MESSAGE_SRC (message));
* gst_video_overlay_set_window_handle (overlay, video_window_handle);
* } else {
* g_warning ("Should have obtained video_window_handle by now!");
* }
*
* gst_message_unref (message);
* return GST_BUS_DROP;
* }
* ...
* static void
* video_widget_realize_cb (GtkWidget * widget, gpointer data)
* {
* #if GTK_CHECK_VERSION(2,18,0)
* // Tell Gtk+/Gdk to create a native window for this widget instead of
* // drawing onto the parent widget.
* // This is here just for pedagogical purposes, GDK_WINDOW_XID will call
* // it as well in newer Gtk versions
* if (!gdk_window_ensure_native (widget->window))
* g_error ("Couldn't create native window needed for GstVideoOverlay!");
* #endif
*
* #ifdef GDK_WINDOWING_X11
* {
* gulong xid = GDK_WINDOW_XID (gtk_widget_get_window (video_window));
* video_window_handle = xid;
* }
* #endif
* #ifdef GDK_WINDOWING_WIN32
* {
* HWND wnd = GDK_WINDOW_HWND (gtk_widget_get_window (video_window));
* video_window_handle = (guintptr) wnd;
* }
* #endif
* }
* ...
* int
* main (int argc, char **argv)
* {
* GtkWidget *video_window;
* GtkWidget *app_window;
* ...
* app_window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
* ...
* video_window = gtk_drawing_area_new ();
* g_signal_connect (video_window, "realize",
* G_CALLBACK (video_widget_realize_cb), NULL);
* gtk_widget_set_double_buffered (video_window, FALSE);
* ...
* // usually the video_window will not be directly embedded into the
* // application window like this, but there will be many other widgets
* // and the video window will be embedded in one of them instead
* gtk_container_add (GTK_CONTAINER (ap_window), video_window);
* ...
* // show the GUI
* gtk_widget_show_all (app_window);
*
* // realize window now so that the video window gets created and we can
* // obtain its XID/HWND before the pipeline is started up and the videosink
* // asks for the XID/HWND of the window to render onto
* gtk_widget_realize (video_window);
*
* // we should have the XID/HWND now
* g_assert (video_window_handle != 0);
* ...
* // set up sync handler for setting the xid once the pipeline is started
* bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline));
* gst_bus_set_sync_handler (bus, (GstBusSyncHandler) bus_sync_handler, NULL,
* NULL);
* gst_object_unref (bus);
* ...
* gst_element_set_state (pipeline, GST_STATE_PLAYING);
* ...
* }
* ]|
*
* ## GstVideoOverlay and Qt
*
* |[
* #include <glib.h>
* #include <gst/gst.h>
* #include <gst/video/videooverlay.h>
*
* #include <QApplication>
* #include <QTimer>
* #include <QWidget>
*
* int main(int argc, char *argv[])
* {
* if (!g_thread_supported ())
* g_thread_init (NULL);
*
* gst_init (&argc, &argv);
* QApplication app(argc, argv);
* app.connect(&app, SIGNAL(lastWindowClosed()), &app, SLOT(quit ()));
*
* // prepare the pipeline
*
* GstElement *pipeline = gst_pipeline_new ("xvoverlay");
* GstElement *src = gst_element_factory_make ("videotestsrc", NULL);
* GstElement *sink = gst_element_factory_make ("xvimagesink", NULL);
* gst_bin_add_many (GST_BIN (pipeline), src, sink, NULL);
* gst_element_link (src, sink);
*
* // prepare the ui
*
* QWidget window;
* window.resize(320, 240);
* window.show();
*
* WId xwinid = window.winId();
* gst_video_overlay_set_window_handle (GST_VIDEO_OVERLAY (sink), xwinid);
*
* // run the pipeline
*
* GstStateChangeReturn sret = gst_element_set_state (pipeline,
* GST_STATE_PLAYING);
* if (sret == GST_STATE_CHANGE_FAILURE) {
* gst_element_set_state (pipeline, GST_STATE_NULL);
* gst_object_unref (pipeline);
* // Exit application
* QTimer::singleShot(0, QApplication::activeWindow(), SLOT(quit()));
* }
*
* int ret = app.exec();
*
* window.hide();
* gst_element_set_state (pipeline, GST_STATE_NULL);
* gst_object_unref (pipeline);
*
* return ret;
* }
* ]|
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "videooverlay.h"
enum
{
PROP_RENDER_RECTANGLE,
};
GST_DEBUG_CATEGORY_STATIC (gst_video_overlay_debug);
#define GST_CAT_DEFAULT gst_video_overlay_debug
GType
gst_video_overlay_get_type (void)
{
static GType gst_video_overlay_type = 0;
if (!gst_video_overlay_type) {
static const GTypeInfo gst_video_overlay_info = {
sizeof (GstVideoOverlayInterface),
NULL,
NULL,
NULL,
NULL,
NULL,
0,
0,
NULL,
};
gst_video_overlay_type = g_type_register_static (G_TYPE_INTERFACE,
"GstVideoOverlay", &gst_video_overlay_info, 0);
GST_DEBUG_CATEGORY_INIT (gst_video_overlay_debug, "videooverlay", 0,
"videooverlay interface");
}
return gst_video_overlay_type;
}
/**
* gst_video_overlay_set_window_handle:
* @overlay: a #GstVideoOverlay to set the window on.
* @handle: a handle referencing the window.
*
* This will call the video overlay's set_window_handle method. You
* should use this method to tell to an overlay to display video output to a
* specific window (e.g. an XWindow on X11). Passing 0 as the @handle will
* tell the overlay to stop using that window and create an internal one.
*/
void
gst_video_overlay_set_window_handle (GstVideoOverlay * overlay, guintptr handle)
{
GstVideoOverlayInterface *iface;
g_return_if_fail (overlay != NULL);
g_return_if_fail (GST_IS_VIDEO_OVERLAY (overlay));
iface = GST_VIDEO_OVERLAY_GET_INTERFACE (overlay);
if (iface->set_window_handle) {
iface->set_window_handle (overlay, handle);
}
}
/**
* gst_video_overlay_got_window_handle:
* @overlay: a #GstVideoOverlay which got a window
* @handle: a platform-specific handle referencing the window
*
* This will post a "have-window-handle" element message on the bus.
*
* This function should only be used by video overlay plugin developers.
*/
void
gst_video_overlay_got_window_handle (GstVideoOverlay * overlay, guintptr handle)
{
GstStructure *s;
GstMessage *msg;
g_return_if_fail (overlay != NULL);
g_return_if_fail (GST_IS_VIDEO_OVERLAY (overlay));
GST_LOG_OBJECT (GST_OBJECT (overlay), "window_handle = %p", (gpointer)
handle);
s = gst_structure_new ("have-window-handle",
"window-handle", G_TYPE_UINT64, (guint64) handle, NULL);
msg = gst_message_new_element (GST_OBJECT (overlay), s);
gst_element_post_message (GST_ELEMENT (overlay), msg);
}
/**
* gst_video_overlay_prepare_window_handle:
* @overlay: a #GstVideoOverlay which does not yet have an Window handle set
*
* This will post a "prepare-window-handle" element message on the bus
* to give applications an opportunity to call
* gst_video_overlay_set_window_handle() before a plugin creates its own
* window.
*
* This function should only be used by video overlay plugin developers.
*/
void
gst_video_overlay_prepare_window_handle (GstVideoOverlay * overlay)
{
GstStructure *s;
GstMessage *msg;
g_return_if_fail (overlay != NULL);
g_return_if_fail (GST_IS_VIDEO_OVERLAY (overlay));
GST_LOG_OBJECT (GST_OBJECT (overlay), "prepare window handle");
s = gst_structure_new_empty ("prepare-window-handle");
msg = gst_message_new_element (GST_OBJECT (overlay), s);
gst_element_post_message (GST_ELEMENT (overlay), msg);
}
/**
* gst_video_overlay_expose:
* @overlay: a #GstVideoOverlay to expose.
*
* Tell an overlay that it has been exposed. This will redraw the current frame
* in the drawable even if the pipeline is PAUSED.
*/
void
gst_video_overlay_expose (GstVideoOverlay * overlay)
{
GstVideoOverlayInterface *iface;
g_return_if_fail (overlay != NULL);
g_return_if_fail (GST_IS_VIDEO_OVERLAY (overlay));
iface = GST_VIDEO_OVERLAY_GET_INTERFACE (overlay);
if (iface->expose) {
iface->expose (overlay);
}
}
/**
* gst_video_overlay_handle_events:
* @overlay: a #GstVideoOverlay to expose.
* @handle_events: a #gboolean indicating if events should be handled or not.
*
* Tell an overlay that it should handle events from the window system. These
* events are forwarded 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 #GstVideoOverlay.
*/
void
gst_video_overlay_handle_events (GstVideoOverlay * overlay,
gboolean handle_events)
{
GstVideoOverlayInterface *iface;
g_return_if_fail (overlay != NULL);
g_return_if_fail (GST_IS_VIDEO_OVERLAY (overlay));
iface = GST_VIDEO_OVERLAY_GET_INTERFACE (overlay);
if (iface->handle_events) {
iface->handle_events (overlay, handle_events);
}
}
/**
* gst_video_overlay_set_render_rectangle:
* @overlay: a #GstVideoOverlay
* @x: the horizontal offset of the render area inside the window
* @y: the vertical offset of the render area inside the window
* @width: the width of the render area inside the window
* @height: the height of the render area inside the window
*
* Configure a subregion as a video target within the window set by
* gst_video_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_video_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.
*
* Returns: %FALSE if not supported by the sink.
*/
gboolean
gst_video_overlay_set_render_rectangle (GstVideoOverlay * overlay,
gint x, gint y, gint width, gint height)
{
GstVideoOverlayInterface *iface;
g_return_val_if_fail (overlay != NULL, FALSE);
g_return_val_if_fail (GST_IS_VIDEO_OVERLAY (overlay), FALSE);
g_return_val_if_fail ((width == -1 && height == -1) ||
(width > 0 && height > 0), FALSE);
iface = GST_VIDEO_OVERLAY_GET_INTERFACE (overlay);
if (iface->set_render_rectangle) {
iface->set_render_rectangle (overlay, x, y, width, height);
return TRUE;
}
return FALSE;
}
/**
* gst_is_video_overlay_prepare_window_handle_message:
* @msg: a #GstMessage
*
* Convenience function to check if the given message is a
* "prepare-window-handle" message from a #GstVideoOverlay.
*
* Returns: whether @msg is a "prepare-window-handle" message
*/
gboolean
gst_is_video_overlay_prepare_window_handle_message (GstMessage * msg)
{
g_return_val_if_fail (msg != NULL, FALSE);
if (GST_MESSAGE_TYPE (msg) != GST_MESSAGE_ELEMENT)
return FALSE;
return gst_message_has_name (msg, "prepare-window-handle");
}
/**
* gst_video_overlay_install_properties:
* @oclass: The class on which the properties will be installed
* @last_prop_id: The first free property ID to use
*
* This helper shall be used by classes implementing the #GstVideoOverlay
* interface that want the render rectangle to be controllable using
* properties. This helper will install "render-rectangle" property into the
* class.
*
* Since 1.14
*/
void
gst_video_overlay_install_properties (GObjectClass * oclass, gint last_prop_id)
{
g_object_class_install_property (oclass, last_prop_id + PROP_RENDER_RECTANGLE,
gst_param_spec_array ("render-rectangle", "Render Rectangle",
"The render rectangle ('<x, y, width, height>')",
g_param_spec_int ("rect-value", "Rectangle Value",
"One of x, y, width or height value.", -1, G_MAXINT, -1,
G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS),
G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
}
/**
* gst_video_overlay_set_property:
* @object: The instance on which the property is set
* @last_prop_id: The highest property ID.
* @property_id: The property ID
* @value: The #GValue to be set
*
* This helper shall be used by classes implementing the #GstVideoOverlay
* interface that want the render rectangle to be controllable using
* properties. This helper will parse and set the render rectangle calling
* gst_video_overlay_set_render_rectangle().
*
* Returns: %TRUE if the @property_id matches the GstVideoOverlay property
*
* Since 1.14
*/
gboolean
gst_video_overlay_set_property (GObject * object, gint last_prop_id,
guint property_id, const GValue * value)
{
gboolean ret = FALSE;
if (property_id == last_prop_id) {
const GValue *v;
gint rect[4], i;
ret = TRUE;
if (gst_value_array_get_size (value) != 4)
goto wrong_format;
for (i = 0; i < 4; i++) {
v = gst_value_array_get_value (value, i);
if (!G_VALUE_HOLDS_INT (v))
goto wrong_format;
rect[i] = g_value_get_int (v);
}
gst_video_overlay_set_render_rectangle (GST_VIDEO_OVERLAY (object),
rect[0], rect[1], rect[2], rect[3]);
}
return ret;
wrong_format:
{
GValue string = G_VALUE_INIT;
g_value_init (&string, G_TYPE_STRING);
g_value_transform (value, &string);
g_critical ("Badly formated rectangle, must contains four gint (got '%s')",
g_value_get_string (&string));
g_value_unset (&string);
return TRUE;
}
}