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<title>GStreamer Base Plugins 1.0 Library Reference Manual: gstvideooverlay</title>
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<a name="gst-plugins-base-libs-gstvideooverlay"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2><span class="refentrytitle"><a name="gst-plugins-base-libs-gstvideooverlay.top_of_page"></a>gstvideooverlay</span></h2>
<p>gstvideooverlay — Interface for setting/getting a window system resource
on elements supporting it to configure a window into which to render a
video.</p>
</td>
<td class="gallery_image" valign="top" align="right"></td>
</tr></table></div>
<div class="refsect1">
<a name="gst-plugins-base-libs-gstvideooverlay.functions"></a><h2>Functions</h2>
<div class="informaltable"><table width="100%" border="0">
<colgroup>
<col width="150px" class="functions_return">
<col class="functions_name">
</colgroup>
<tbody>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-video-overlay-got-window-handle" title="gst_video_overlay_got_window_handle ()">gst_video_overlay_got_window_handle</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-video-overlay-set-window-handle" title="gst_video_overlay_set_window_handle ()">gst_video_overlay_set_window_handle</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-video-overlay-prepare-window-handle" title="gst_video_overlay_prepare_window_handle ()">gst_video_overlay_prepare_window_handle</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-video-overlay-expose" title="gst_video_overlay_expose ()">gst_video_overlay_expose</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-video-overlay-handle-events" title="gst_video_overlay_handle_events ()">gst_video_overlay_handle_events</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-video-overlay-set-render-rectangle" title="gst_video_overlay_set_render_rectangle ()">gst_video_overlay_set_render_rectangle</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
</td>
<td class="function_name">
<a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-is-video-overlay-prepare-window-handle-message" title="gst_is_video_overlay_prepare_window_handle_message ()">gst_is_video_overlay_prepare_window_handle_message</a> <span class="c_punctuation">()</span>
</td>
</tr>
</tbody>
</table></div>
</div>
<a name="GstVideoOverlay"></a><div class="refsect1">
<a name="gst-plugins-base-libs-gstvideooverlay.other"></a><h2>Types and Values</h2>
<div class="informaltable"><table width="100%" border="0">
<colgroup>
<col width="150px" class="name">
<col class="description">
</colgroup>
<tbody>
<tr>
<td class="datatype_keyword"> </td>
<td class="function_name"><a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay-struct" title="GstVideoOverlay">GstVideoOverlay</a></td>
</tr>
<tr>
<td class="datatype_keyword">struct</td>
<td class="function_name"><a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlayInterface" title="struct GstVideoOverlayInterface">GstVideoOverlayInterface</a></td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="gst-plugins-base-libs-gstvideooverlay.object-hierarchy"></a><h2>Object Hierarchy</h2>
<pre class="screen"> GInterface
<span class="lineart">╰──</span> GstVideoOverlay
</pre>
</div>
<div class="refsect1">
<a name="gst-plugins-base-libs-gstvideooverlay.includes"></a><h2>Includes</h2>
<pre class="synopsis">#include <gst/video/videooverlay.h>
</pre>
</div>
<div class="refsect1">
<a name="gst-plugins-base-libs-gstvideooverlay.description"></a><h2>Description</h2>
<div class="refsect2">
<a name="id-1.2.14.11.8.2"></a><p>
The <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> interface is used for 2 main purposes :
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem"><p>
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.
</p></li>
<li class="listitem"><p>
To force a redrawing of the latest video frame the video sink element
displayed on the Window. Indeed if the <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstPipeline.html"><span class="type">GstPipeline</span></a> is in <span class="type">GST_STATE_PAUSED</span>
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.
</p></li>
</ul></div>
<p>
</p>
<p>
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.
</p>
<p>
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 <a href="/usr/share/gtk-doc/html/gstreamer-1.0/gstreamer-GstMessage.html#GstMessage"><span class="type">GstMessage</span></a> 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:
</p>
<div class="informalexample"><pre class="programlisting">
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);
...
}
</pre></div>
<p>
</p>
</div>
<hr>
<div class="refsect2">
<a name="id-1.2.14.11.8.3"></a><h3>Two basic usage scenarios</h3>
<p>
There are two basic usage scenarios: in the simplest case, the application
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. <span class="type">xvimagesink</span>, <span class="type">ximagesink</span>, 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 <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-video-overlay-set-window-handle" title="gst_video_overlay_set_window_handle ()"><code class="function">gst_video_overlay_set_window_handle()</code></a> directly
with the XID or native window handle, before starting up the pipeline.
</p>
<p>
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 <span class="type">autovideosink</span> or <span class="type">gconfvideosink</span>
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).
</p>
<p>
As response to the prepare-window-handle element message in the bus sync
handler, the application may use <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-video-overlay-set-window-handle" title="gst_video_overlay_set_window_handle ()"><code class="function">gst_video_overlay_set_window_handle()</code></a> 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
<code class="function">GDK_WINDOW_XID()</code> 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 <code class="function">GDK_WINDOW_XID()</code>
used in the callback).
</p>
</div>
<hr>
<div class="refsect2">
<a name="id-1.2.14.11.8.4"></a><h3>GstVideoOverlay and Gtk+</h3>
<p>
</p>
<div class="informalexample"><pre class="programlisting">
#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);
...
}
</pre></div>
<p>
</p>
</div>
<hr>
<div class="refsect2">
<a name="id-1.2.14.11.8.5"></a><h3>GstVideoOverlay and Qt</h3>
<p>
</p>
<div class="informalexample"><pre class="programlisting">
#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;
}
</pre></div>
<p>
</p>
</div>
</div>
<div class="refsect1">
<a name="gst-plugins-base-libs-gstvideooverlay.functions_details"></a><h2>Functions</h2>
<div class="refsect2">
<a name="gst-video-overlay-got-window-handle"></a><h3>gst_video_overlay_got_window_handle ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_video_overlay_got_window_handle (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> *overlay</code></em>,
<em class="parameter"><code><span class="type">guintptr</span> handle</code></em>);</pre>
<p>This will post a "have-window-handle" element message on the bus.</p>
<p>This function should only be used by video overlay plugin developers.</p>
<div class="refsect3">
<a name="id-1.2.14.11.9.2.6"></a><h4>Parameters</h4>
<div class="informaltable"><table width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>overlay</p></td>
<td class="parameter_description"><p>a <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> which got a window</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>handle</p></td>
<td class="parameter_description"><p>a platform-specific handle referencing the window</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-video-overlay-set-window-handle"></a><h3>gst_video_overlay_set_window_handle ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_video_overlay_set_window_handle (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> *overlay</code></em>,
<em class="parameter"><code><span class="type">guintptr</span> handle</code></em>);</pre>
<p>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 <em class="parameter"><code>handle</code></em>
will
tell the overlay to stop using that window and create an internal one.</p>
<div class="refsect3">
<a name="id-1.2.14.11.9.3.5"></a><h4>Parameters</h4>
<div class="informaltable"><table width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>overlay</p></td>
<td class="parameter_description"><p>a <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> to set the window on.</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>handle</p></td>
<td class="parameter_description"><p>a handle referencing the window.</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-video-overlay-prepare-window-handle"></a><h3>gst_video_overlay_prepare_window_handle ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_video_overlay_prepare_window_handle
(<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> *overlay</code></em>);</pre>
<p>This will post a "prepare-window-handle" element message on the bus
to give applications an opportunity to call
<a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-video-overlay-set-window-handle" title="gst_video_overlay_set_window_handle ()"><code class="function">gst_video_overlay_set_window_handle()</code></a> before a plugin creates its own
window.</p>
<p>This function should only be used by video overlay plugin developers.</p>
<div class="refsect3">
<a name="id-1.2.14.11.9.4.6"></a><h4>Parameters</h4>
<div class="informaltable"><table width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>overlay</p></td>
<td class="parameter_description"><p>a <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> which does not yet have an Window handle set</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-video-overlay-expose"></a><h3>gst_video_overlay_expose ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_video_overlay_expose (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> *overlay</code></em>);</pre>
<p>Tell an overlay that it has been exposed. This will redraw the current frame
in the drawable even if the pipeline is PAUSED.</p>
<div class="refsect3">
<a name="id-1.2.14.11.9.5.5"></a><h4>Parameters</h4>
<div class="informaltable"><table width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>overlay</p></td>
<td class="parameter_description"><p>a <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> to expose.</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-video-overlay-handle-events"></a><h3>gst_video_overlay_handle_events ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
gst_video_overlay_handle_events (<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> *overlay</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> handle_events</code></em>);</pre>
<p>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 <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a>.</p>
<div class="refsect3">
<a name="id-1.2.14.11.9.6.5"></a><h4>Parameters</h4>
<div class="informaltable"><table width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>overlay</p></td>
<td class="parameter_description"><p>a <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> to expose.</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>handle_events</p></td>
<td class="parameter_description"><p>a <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="type">gboolean</span></a> indicating if events should be handled or not.</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-video-overlay-set-render-rectangle"></a><h3>gst_video_overlay_set_render_rectangle ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
gst_video_overlay_set_render_rectangle
(<em class="parameter"><code><a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> *overlay</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> x</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> y</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> width</code></em>,
<em class="parameter"><code><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a> height</code></em>);</pre>
<p>Configure a subregion as a video target within the window set by
<a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-video-overlay-set-window-handle" title="gst_video_overlay_set_window_handle ()"><code class="function">gst_video_overlay_set_window_handle()</code></a>. 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
<a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#gst-video-overlay-expose" title="gst_video_overlay_expose ()"><code class="function">gst_video_overlay_expose()</code></a> to force a redraw. To unset the region pass -1 for
the <em class="parameter"><code>width</code></em>
and <em class="parameter"><code>height</code></em>
parameters.</p>
<p>This method is needed for non fullscreen video overlay in UI toolkits that
do not support subwindows.</p>
<div class="refsect3">
<a name="id-1.2.14.11.9.7.6"></a><h4>Parameters</h4>
<div class="informaltable"><table width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>overlay</p></td>
<td class="parameter_description"><p>a <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>x</p></td>
<td class="parameter_description"><p>the horizontal offset of the render area inside the window</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>y</p></td>
<td class="parameter_description"><p>the vertical offset of the render area inside the window</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>width</p></td>
<td class="parameter_description"><p>the width of the render area inside the window</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>height</p></td>
<td class="parameter_description"><p>the height of the render area inside the window</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="id-1.2.14.11.9.7.7"></a><h4>Returns</h4>
<p> <a href="/usr/share/gtk-doc/html/glib/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> if not supported by the sink.</p>
<p></p>
</div>
</div>
<hr>
<div class="refsect2">
<a name="gst-is-video-overlay-prepare-window-handle-message"></a><h3>gst_is_video_overlay_prepare_window_handle_message ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a>
gst_is_video_overlay_prepare_window_handle_message
(<em class="parameter"><code><a href="/usr/share/gtk-doc/html/gstreamer-1.0/gstreamer-GstMessage.html#GstMessage"><span class="type">GstMessage</span></a> *msg</code></em>);</pre>
<p>Convenience function to check if the given message is a
"prepare-window-handle" message from a <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a>.</p>
<div class="refsect3">
<a name="id-1.2.14.11.9.8.5"></a><h4>Parameters</h4>
<div class="informaltable"><table width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>msg</p></td>
<td class="parameter_description"><p>a <a href="/usr/share/gtk-doc/html/gstreamer-1.0/gstreamer-GstMessage.html#GstMessage"><span class="type">GstMessage</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="id-1.2.14.11.9.8.6"></a><h4>Returns</h4>
<p> whether <em class="parameter"><code>msg</code></em>
is a "prepare-window-handle" message</p>
<p></p>
</div>
</div>
</div>
<div class="refsect1">
<a name="gst-plugins-base-libs-gstvideooverlay.other_details"></a><h2>Types and Values</h2>
<div class="refsect2">
<a name="GstVideoOverlay-struct"></a><h3>GstVideoOverlay</h3>
<pre class="programlisting">typedef struct _GstVideoOverlay GstVideoOverlay;</pre>
<p>Opaque <a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> interface structure</p>
</div>
<hr>
<div class="refsect2">
<a name="GstVideoOverlayInterface"></a><h3>struct GstVideoOverlayInterface</h3>
<pre class="programlisting">struct GstVideoOverlayInterface {
GTypeInterface iface;
/* virtual functions */
void (*expose) (GstVideoOverlay *overlay);
void (*handle_events) (GstVideoOverlay *overlay, gboolean handle_events);
void (*set_render_rectangle) (GstVideoOverlay *overlay,
gint x, gint y,
gint width, gint height);
void (*set_window_handle) (GstVideoOverlay *overlay, guintptr handle);
};
</pre>
<p><a class="link" href="gst-plugins-base-libs-gstvideooverlay.html#GstVideoOverlay"><span class="type">GstVideoOverlay</span></a> interface</p>
<div class="refsect3">
<a name="id-1.2.14.11.10.3.5"></a><h4>Members</h4>
<div class="informaltable"><table width="100%" border="0">
<colgroup>
<col width="300px" class="struct_members_name">
<col class="struct_members_description">
<col width="200px" class="struct_members_annotations">
</colgroup>
<tbody>
<tr>
<td class="struct_member_name"><p><a href="/usr/share/gtk-doc/html/gobject/gobject-Type-Information.html#GTypeInterface"><span class="type">GTypeInterface</span></a> <em class="structfield"><code><a name="GstVideoOverlayInterface.iface"></a>iface</code></em>;</p></td>
<td class="struct_member_description"><p>parent interface type.</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstVideoOverlayInterface.expose"></a>expose</code></em> ()</p></td>
<td class="struct_member_description"><p>virtual method to handle expose events</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstVideoOverlayInterface.handle-events"></a>handle_events</code></em> ()</p></td>
<td class="struct_member_description"><p>virtual method to handle events</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstVideoOverlayInterface.set-render-rectangle"></a>set_render_rectangle</code></em> ()</p></td>
<td class="struct_member_description"><p>virtual method to set the render rectangle</p></td>
<td class="struct_member_annotations"> </td>
</tr>
<tr>
<td class="struct_member_name"><p><em class="structfield"><code><a name="GstVideoOverlayInterface.set-window-handle"></a>set_window_handle</code></em> ()</p></td>
<td class="struct_member_description"><p>virtual method to configure the window handle</p></td>
<td class="struct_member_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
</div>
</div>
</div>
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