Event handling in the Gstreamer glimagesink

glsink-input.py

#!/usr/bin/env python3

from gi.repository import Gdk, Gtk, Gst

import signal
signal.signal(signal.SIGINT, signal.SIG_DFL)

class GstOverlaySink(Gtk.DrawingArea):
    def __init__(self, name, w, h):
        Gtk.DrawingArea.__init__(self)
        from gi.repository import GdkX11, GstVideo

        self.sink = Gst.ElementFactory.make(name, None)
        self.set_size_request(w, h)
        
        self.connect("motion-notify-event", self.on_motion)
        self.connect("button-press-event", self.on_press)
        self.connect("button-release-event", self.on_release)
        
        """
        When handle_events is set to True (Default, when nothing is set here)
        Only the press event is captured when setting Gdk events
        The motion event is captured only "on drag", when press is triggered
        The BUTTON_PRESS_MASK needs to be set for the POINTER_MOTION_MASK 
        to work during drag. ALL_EVENTS_MASK also works.
        The motion event does not work without drag.
        Also setting custom cursors does not work.
        """
        # self.sink.handle_events (True)
        # self.add_events(Gdk.EventMask.BUTTON_PRESS_MASK)
        # self.add_events(Gdk.EventMask.POINTER_MOTION_MASK)
        # or
        #self.add_events(Gdk.EventMask.ALL_EVENTS_MASK)
        
        """
        When handle_events is set to False
        The behaviour is the same as in the xvimagesink
        """
        self.sink.handle_events (False)
        self.add_events(Gdk.EventMask.BUTTON_PRESS_MASK)
        self.add_events(Gdk.EventMask.BUTTON_RELEASE_MASK)
        self.add_events(Gdk.EventMask.POINTER_MOTION_MASK)
        
    def on_press(self, sink, event):
        print("press")
        
    def on_release(self, sink, event):
        print("release")
        
    def on_motion(self, sink, event):
        print(event.x, event.y)
        
    def xid(self):
        return self.get_window().get_xid()

    def set_handle(self):
        self.sink.set_window_handle(self.xid())


def quit_app(widget):
    widget.hide()
    Gtk.main_quit()


def window_closed(widget, event):
    quit_app(widget)


def key_pressed(widget, key):
    if key.keyval == Gdk.KEY_Escape:
        quit_app(widget)

Gtk.init([])
Gst.init([])

window = Gtk.Window()
window.connect("delete-event", window_closed)
window.set_default_size(640, 480)
window.set_title("Foo")

pipeline = Gst.Pipeline()
src = Gst.ElementFactory.make("gltestsrc", None)
sink = GstOverlaySink("glimagesink", 640, 480)
#sink = GstOverlaySink("xvimagesink", 640, 480)

pipeline.add(src, sink.sink)
src.link(sink.sink)

window.add(sink)
window.show_all()

sink.set_handle()

if pipeline.set_state(Gst.State.PLAYING) == Gst.StateChangeReturn.FAILURE:
    pipeline.set_state(Gst.State.NULL)
else:
    Gtk.main()