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<div class=Section1>
<p class=MsoNormal>Hi everybody,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I am writing an application where the user should be able to
draw (with the mouse) a rectangle on a playing video window (for now it is an
ximagesink).<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I try the following but I see nothing drawing on the screen…<o:p></o:p></p>
<p class=MsoNormal>### CONFIGURE PIPELINE TO CATCH SYNC MESSAGES<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:.5in'>bus = self.Pipeline.get_bus()<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:.5in'>bus.add_signal_watch()<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:.5in'>bus.enable_sync_message_emission()<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:.5in'>bus.connect('message',
self.on_message)<o:p></o:p></p>
<p class=MsoPlainText style='margin-left:.5in'>bus.connect('sync-message::element',
self.on_sync_message)<o:p></o:p></p>
<p class=MsoNormal style='text-indent:.5in'><o:p> </o:p></p>
<p class=MsoNormal style='text-indent:.5in'><o:p> </o:p></p>
<p class=MsoNormal style='text-indent:.5in'>#############<o:p></o:p></p>
<p class=MsoNormal style='text-indent:.5in'>## Tell ximagesink to draw into the
draw area that I give it, not in it’s own …<o:p></o:p></p>
<p class=MsoPlainText> def on_sync_message(self, bus,
message):<o:p></o:p></p>
<p class=MsoPlainText> if message.structure is None:<o:p></o:p></p>
<p class=MsoPlainText> return<o:p></o:p></p>
<p class=MsoPlainText> message_name =
message.structure.get_name()<o:p></o:p></p>
<p class=MsoPlainText> if message_name ==
"prepare-xwindow-id":<o:p></o:p></p>
<p class=MsoPlainText> imagesink
= message.src<o:p></o:p></p>
<p class=MsoPlainText> imagesink.set_property("force-aspect-ratio",
True)<o:p></o:p></p>
<p class=MsoPlainText> imagesink.set_xwindow_id(self.DrawingArea.window.xid)<o:p></o:p></p>
<p class=MsoNormal style='text-indent:.5in'><o:p> </o:p></p>
<p class=MsoNormal style='text-indent:.5in'>#############<o:p></o:p></p>
<p class=MsoNormal style='text-indent:.5in'>## Now, on the expose event of the
drawing area, paint the rectangle according to user input (mouse)<o:p></o:p></p>
<p class=MsoNormal style='text-indent:.5in'>#############<o:p></o:p></p>
<p class=MsoPlainText> def
on_DrawingAreaCamera_expose_event(self,widget,event):<o:p></o:p></p>
<p class=MsoPlainText> #if
self.area_selection_now is True:<o:p></o:p></p>
<p class=MsoPlainText> context =
widget.window.cairo_create()<o:p></o:p></p>
<p class=MsoPlainText>
#widget.window.draw(context)<o:p></o:p></p>
<p class=MsoPlainText>
context.rectangle(self.area_selection)<o:p></o:p></p>
<p class=MsoPlainText>
context.set_source_rgb(1,0,0)<o:p></o:p></p>
<p class=MsoPlainText>
context.stroke()<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>What is the right way to interact with ximagesink, so I can
also draw things on it’s drawable??<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Regards<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
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