无法用覆盖Gstreamer视频Gtk覆盖

Question

我有一个使用Python、PyGObject（gtk3）和GStreamer（0.11）的项目

我的应用程序中有视频，所以我使用Gtk覆盖小部件，我可以把其他视觉元素放在视频背景上。（我需要这个，相信我。）（由于widget的数量，以及对这些widget的特定定位和覆盖的需要，我使用一个Gtk.固定集装箱。）

但是，在使用Gtk覆盖对象通过“”添加任何内容overlay.add_覆盖（widget）“，视频不再可见。我还能听到，但我看不见。在

代码如下。在

from gi.repository import Gtk, Gdk, GdkPixbuf, GdkX11
import pango
import pygst
pygst.require('0.10')
import gst
import Trailcrest
import os, sys
import cairo
from math import pi

class Video:

    def __init__(self):

        def on_message(bus, message): 
            if message.type == gst.MESSAGE_EOS: 
                # End of Stream 
                player.seek(1.0, gst.FORMAT_TIME, gst.SEEK_FLAG_FLUSH, gst.SEEK_TYPE_SET, 5000000000, gst.SEEK_TYPE_NONE, 6000000000)
            elif message.type == gst.MESSAGE_ERROR: 
                player.set_state(gst.STATE_NULL) 
                (err, debug) = message.parse_error() 
                print "Error: %s" % err, debug

        def on_sync_message(bus, message):
            if message.structure is None:
                return False
            if message.structure.get_name() == "prepare-xwindow-id":
                Gdk.threads_enter()
                Gdk.Display.get_default().sync()
                win_id = videowidget.get_property('window').get_xid()
                imagesink = message.src
                imagesink.set_property("force-aspect-ratio", True)
                imagesink.set_xwindow_id(win_id)
                Gdk.threads_leave()

        def click_me(event, data=None):
            player.seek(1.0, gst.FORMAT_TIME, gst.SEEK_FLAG_FLUSH, gst.SEEK_TYPE_SET, 5000000000, gst.SEEK_TYPE_NONE, 6000000000)

        win = Gtk.Window()
        win.set_resizable(False)
        win.set_decorated(False)
        win.set_position(Gtk.WindowPosition.CENTER)

        overlay = Gtk.Overlay()
        win.add(overlay)
        overlay.show()

        videowidget = Gtk.DrawingArea()
        overlay.add(videowidget)
        videowidget.set_halign (Gtk.Align.START)
        videowidget.set_valign (Gtk.Align.START)
        videowidget.set_size_request(640, 480)
        videowidget.show()

        fixed = Gtk.Fixed()
        overlay.add_overlay(fixed)
        fixed.show()

        pixbuf = GdkPixbuf.Pixbuf.new_from_file_at_size("IMG/IMG-MPG-LOGO.png", 250, 50)
        imgMPL = Gtk.Image()
        imgMPL.set_from_pixbuf(pixbuf)
        eb_imgMPL = Gtk.EventBox()
        eb_imgMPL.set_visible_window(False)
        eb_imgMPL.add(imgMPL)
        fixed.put(eb_imgMPL, 10, 10)
        imgMPL.show()
        eb_imgMPL.show()

        win.show_all()

        # Setup GStreamer 
        player = gst.element_factory_make("playbin", "MultimediaPlayer")
        bus = player.get_bus() 
        bus.add_signal_watch() 
        bus.enable_sync_message_emission() 
        #used to get messages that GStreamer emits 
        bus.connect("message", on_message) 
        #used for connecting video to your application 
        bus.connect("sync-message::element", on_sync_message)
        player.set_property("uri", "file://" + os.getcwd() + "/VID/BGA-HABT-001.ogv")
        player.set_state(gst.STATE_PLAYING)


if __name__ == "__main__":
    Gdk.threads_enter()
    Video()
    Gtk.main()

我怎么解决这个小问题？在

Answer 1

Answer derived from GNOME Bugzilla Bug 663589, Comments 1-3.

设置通过“添加覆盖”添加的任何对象的valign和halign至关重要。在

因此，修订后的代码Gtk.固定对象如下。在

fixed = Gtk.Fixed()

#The following two lines were added.
fixed.set_halign(Gtk.Align.START)
fixed.set_valign(Gtk.Align.START)

overlay.add_overlay(fixed)
fixed.show()