Skip to content
  • Categories
  • Recent
  • Tags
  • Popular
  • Users
  • Groups
  • Search
  • Get Qt Extensions
  • Unsolved
Collapse
Brand Logo
  1. Home
  2. Qt Development
  3. General and Desktop
  4. Qt+Cef integration on Linux
Forum Updated to NodeBB v4.3 + New Features

Qt+Cef integration on Linux

Scheduled Pinned Locked Moved Solved General and Desktop
21 Posts 5 Posters 11.1k Views 3 Watching
  • Oldest to Newest
  • Newest to Oldest
  • Most Votes
Reply
  • Reply as topic
Log in to reply
This topic has been deleted. Only users with topic management privileges can see it.
  • A antofik

    I'm trying to create Qt application with Cef browser working on Linux (Debian Wheezy)
    Versions: Qt 5.5, Cef 1547
    Basically, I have QWidget with following browser initialization code:

    CefwindowInfo info;
    QWindow* win = new QWindow();
    this->layout()->addWidget(QWidget::createWindowContainer(win));
    info.SetAsChild((CefWindowHandle)win->winId());
    CefBrowserHost::CreateBrowser(info, ...);
    

    This code causes Segmentation fault exception with following callstack

    0> g_type_check_instance_cast
    1> CefBrowserHostImpl::PlatformCreateWindow()
    2> ??
    

    If I comment out the line with info.SetAsChild(..) , everything works as expected save that Cef is launched in separate window, while I need it to be integrated in my Qt application.

    Any ideas what am I doing wrong?

    kshegunovK Offline
    kshegunovK Offline
    kshegunov
    Moderators
    wrote on last edited by
    #2

    Hi,
    You're probably passing a nullptr to the SetAsChild method. You should check that as a first step. Secondly, if you're dealing with widgets then the widget may not have a window handle at all (if it's a child to another widget) as Qt optimizes the number of handles used and only root-level widgets get a X window, although a handle should be created when the call is made. And lastly, depending on where you call this code (the snippet) Qt may have not yet created the handle (if at all).

    Kind regards.

    Read and abide by the Qt Code of Conduct

    1 Reply Last reply
    0
    • A Offline
      A Offline
      antofik
      wrote on last edited by
      #3

      Thank you, kshegunov, for you replies.
      SetAsChild receives valid handle. QWindow in Qt was designed specifically to be the point of integration between different windows. I'm running the code in debug mode, so no optimizations are applied. The above code itself is executed without exceptions. The problem happens somewhere inside CefDoMessageLoopWork() later.

      kshegunovK 1 Reply Last reply
      0
      • mrjjM Offline
        mrjjM Offline
        mrjj
        Lifetime Qt Champion
        wrote on last edited by
        #4

        Hi
        Just to be sure.
        Its not CefwindowInfo info;
        running out of scope?

        1 Reply Last reply
        0
        • A Offline
          A Offline
          antofik
          wrote on last edited by
          #5

          No, mrjj, it is not "out-of-scope" issue. The problem is in some kind of validation of QWindow->winId() handle by gnome g_type_check_instance_cast. As if QWindow->winId() returns not the type of object expected by Cef. Should it be GtkWindow*?

          mrjjM 1 Reply Last reply
          0
          • A antofik

            No, mrjj, it is not "out-of-scope" issue. The problem is in some kind of validation of QWindow->winId() handle by gnome g_type_check_instance_cast. As if QWindow->winId() returns not the type of object expected by Cef. Should it be GtkWindow*?

            mrjjM Offline
            mrjjM Offline
            mrjj
            Lifetime Qt Champion
            wrote on last edited by mrjj
            #6

            @antofik
            That could be as
            http://magpcss.org/ceforum/apidocs3/projects/(default)/CefWindowInfo.html#SetAsChild(cef_window_handle_t,RECT)
            Seems to want a cef_window_handle_t and not the Wld (even u cast it)
            Its unclear if it wants one of its own windows or can accept platform "ID"

            A 1 Reply Last reply
            0
            • mrjjM mrjj

              @antofik
              That could be as
              http://magpcss.org/ceforum/apidocs3/projects/(default)/CefWindowInfo.html#SetAsChild(cef_window_handle_t,RECT)
              Seems to want a cef_window_handle_t and not the Wld (even u cast it)
              Its unclear if it wants one of its own windows or can accept platform "ID"

              A Offline
              A Offline
              antofik
              wrote on last edited by
              #7

              @mrjj, you've hit the point. The problem is to pass to SetAsChild() something it will be happy with... But what it is?

              mrjjM 1 Reply Last reply
              0
              • A antofik

                @mrjj, you've hit the point. The problem is to pass to SetAsChild() something it will be happy with... But what it is?

                mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by
                #8

                @antofik
                Well is it make for linux?
                http://magpcss.org/ceforum/apidocs3/projects/(default)/_cef_window_info_t.html
                Really seems windows-ish for me using HWND and DWORD
                Also on the download page
                https://code.google.com/archive/p/chromiumembedded/downloads
                I see no linux?
                Of Course it works on linux too but if u check out the
                cef_window_handle_t ( right click and go to definition)
                is that also using DWORD and HWND or what is the internals in your version?

                A 1 Reply Last reply
                0
                • mrjjM mrjj

                  @antofik
                  Well is it make for linux?
                  http://magpcss.org/ceforum/apidocs3/projects/(default)/_cef_window_info_t.html
                  Really seems windows-ish for me using HWND and DWORD
                  Also on the download page
                  https://code.google.com/archive/p/chromiumembedded/downloads
                  I see no linux?
                  Of Course it works on linux too but if u check out the
                  cef_window_handle_t ( right click and go to definition)
                  is that also using DWORD and HWND or what is the internals in your version?

                  A Offline
                  A Offline
                  antofik
                  wrote on last edited by
                  #9

                  @mrjj
                  Yes, it fully supports Linux. Moreover, it is even embeddable into Qt. But unfortunately there are no open examples.
                  Here https://bitbucket.org/chromiumembedded/cef/src/master/tests/cefclient/cefclient_gtk.cc?at=master&fileviewer=file-view-default you could find an example how to do it with Gtk+. Now, I need to somehow connect Qt and Cef with or without Gtk+ intermediate layer.

                  1 Reply Last reply
                  0
                  • mrjjM Offline
                    mrjjM Offline
                    mrjj
                    Lifetime Qt Champion
                    wrote on last edited by
                    #10

                    Ok, but since you are using the
                    win->winId()
                    That will give you the native handle for a window for the display/deskop manager you are using. ( AFAIK)
                    So if NOT gtk as your desktop, will it then work with Cef ?
                    Are you on KDE or what linux ?

                    1 Reply Last reply
                    0
                    • A antofik

                      Thank you, kshegunov, for you replies.
                      SetAsChild receives valid handle. QWindow in Qt was designed specifically to be the point of integration between different windows. I'm running the code in debug mode, so no optimizations are applied. The above code itself is executed without exceptions. The problem happens somewhere inside CefDoMessageLoopWork() later.

                      kshegunovK Offline
                      kshegunovK Offline
                      kshegunov
                      Moderators
                      wrote on last edited by kshegunov
                      #11

                      @antofik said in Qt+Cef integration on Linux:

                      The problem happens somewhere inside CefDoMessageLoopWork() later.

                      Pull a trace out of that. And also bear in mind Qt very much dislikes sharing the (system) event loop with other things, so I'm still not convinced that integration is possible between these two libraries.

                      Read and abide by the Qt Code of Conduct

                      1 Reply Last reply
                      0
                      • A Offline
                        A Offline
                        antofik
                        wrote on last edited by
                        #12

                        Actually, I've managed to make it work.
                        Just in case, if someone will need it in future:

                          GtkWidget* gtkWin = gtk_window_new(GTK_WINDOW_TOPLEVEL);
                          GtkWidget* parentView = gtk_vbox_new(FALSE, 0);
                          GtkContainer* container = (GTK_CONTAINER(gtkWin));
                          gtk_container_add(container, parentView);
                          gtk_window_set_position(GTK_WINDOW(gtkWin), GTK_WIN_POS_CENTER);
                          gtk_widget_show_all(GTK_WIDGET(gtkWin));
                        
                          GdkWindow* w = gtk_widget_get_window(parentView);
                          XID t = gdk_x11_drawable_get_xid(w);
                        
                          WId wid = (WId) t;
                          QWindow* win = QWindow::fromWinId(wid);
                          setLayout(new QGridLayout());
                          QWidget* widget = QWidget::createWindowContainer(win);
                          this->layout()->addWidget(widget);
                        
                          info.SetAsChild(parentView);
                        

                        Basically, I've created my own GTK window, passed the reference on this window to CEF, and placed it into Qt widget using QWindow::fromWinId().

                        T 1 Reply Last reply
                        1
                        • mrjjM Offline
                          mrjjM Offline
                          mrjj
                          Lifetime Qt Champion
                          wrote on last edited by
                          #13

                          So would it be fair to conclude that it really
                          wants a gtk windows handle and not what ever comes out of
                          winId() ?

                          A 1 Reply Last reply
                          0
                          • mrjjM mrjj

                            So would it be fair to conclude that it really
                            wants a gtk windows handle and not what ever comes out of
                            winId() ?

                            A Offline
                            A Offline
                            antofik
                            wrote on last edited by
                            #14

                            Yes @mrjj, Cef is built on Gtk2, so it requires gtk handle, not the winId().

                            Anyhow, it is possible to integrate Cef with Qt on linux, and that is what matters :-)

                            1 Reply Last reply
                            0
                            • G Offline
                              G Offline
                              gepgep
                              wrote on last edited by
                              #15

                              is there somewhere a more complete example of mixing qt/gtk/cef?

                              mrjjM 1 Reply Last reply
                              0
                              • G gepgep

                                is there somewhere a more complete example of mixing qt/gtk/cef?

                                mrjjM Offline
                                mrjjM Offline
                                mrjj
                                Lifetime Qt Champion
                                wrote on last edited by
                                #16

                                @gepgep
                                Not that i have stumbled upon.
                                Have you asked on the forum ?
                                http://magpcss.org/ceforum/

                                You cannot use http://doc.qt.io/qt-5/qtwebengine-index.html
                                or webkit ?

                                G 1 Reply Last reply
                                0
                                • mrjjM mrjj

                                  @gepgep
                                  Not that i have stumbled upon.
                                  Have you asked on the forum ?
                                  http://magpcss.org/ceforum/

                                  You cannot use http://doc.qt.io/qt-5/qtwebengine-index.html
                                  or webkit ?

                                  G Offline
                                  G Offline
                                  gepgep
                                  wrote on last edited by
                                  #17

                                  @mrjj i am wondering if it can be done with cef due to (my) project restrictions ..
                                  I have found several git repos with qt+cef, but only for windows. Also i managed to combine gtk with cef successfully, but i cant find anything about qt+cef@linux (maybe because qt+gtk is not a happy combination?). The code snippet from @antofik does not build (gtkwidget with qwidget is it even possible) or i am missing something?

                                  mrjjM 1 Reply Last reply
                                  0
                                  • G gepgep

                                    @mrjj i am wondering if it can be done with cef due to (my) project restrictions ..
                                    I have found several git repos with qt+cef, but only for windows. Also i managed to combine gtk with cef successfully, but i cant find anything about qt+cef@linux (maybe because qt+gtk is not a happy combination?). The code snippet from @antofik does not build (gtkwidget with qwidget is it even possible) or i am missing something?

                                    mrjjM Offline
                                    mrjjM Offline
                                    mrjj
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #18

                                    @gepgep
                                    Well mixing Gtk and Qt is pretty rare use case as far as I know. Both being Widgets libraries.
                                    And there is always the issue of the event loop.
                                    So as far as integration it will not be funny.

                                    @antofik sample wraps a gtk window using native Gtk calls +Qt and is apparently supported by
                                    createWindowContainer so in this case it works.

                                    I have not seen much info about this. sorry.

                                    G 1 Reply Last reply
                                    1
                                    • mrjjM mrjj

                                      @gepgep
                                      Well mixing Gtk and Qt is pretty rare use case as far as I know. Both being Widgets libraries.
                                      And there is always the issue of the event loop.
                                      So as far as integration it will not be funny.

                                      @antofik sample wraps a gtk window using native Gtk calls +Qt and is apparently supported by
                                      createWindowContainer so in this case it works.

                                      I have not seen much info about this. sorry.

                                      G Offline
                                      G Offline
                                      gepgep
                                      wrote on last edited by
                                      #19

                                      @mrjj thanks for your time+replies

                                      mrjjM 1 Reply Last reply
                                      0
                                      • G gepgep

                                        @mrjj thanks for your time+replies

                                        mrjjM Offline
                                        mrjjM Offline
                                        mrjj
                                        Lifetime Qt Champion
                                        wrote on last edited by
                                        #20

                                        @gepgep
                                        Hi
                                        Just as a note.
                                        Webkit been revived
                                        https://forum.qt.io/topic/76739/webkit-status-2017

                                        So you might be able to use that?

                                        1 Reply Last reply
                                        1
                                        • A antofik

                                          Actually, I've managed to make it work.
                                          Just in case, if someone will need it in future:

                                            GtkWidget* gtkWin = gtk_window_new(GTK_WINDOW_TOPLEVEL);
                                            GtkWidget* parentView = gtk_vbox_new(FALSE, 0);
                                            GtkContainer* container = (GTK_CONTAINER(gtkWin));
                                            gtk_container_add(container, parentView);
                                            gtk_window_set_position(GTK_WINDOW(gtkWin), GTK_WIN_POS_CENTER);
                                            gtk_widget_show_all(GTK_WIDGET(gtkWin));
                                          
                                            GdkWindow* w = gtk_widget_get_window(parentView);
                                            XID t = gdk_x11_drawable_get_xid(w);
                                          
                                            WId wid = (WId) t;
                                            QWindow* win = QWindow::fromWinId(wid);
                                            setLayout(new QGridLayout());
                                            QWidget* widget = QWidget::createWindowContainer(win);
                                            this->layout()->addWidget(widget);
                                          
                                            info.SetAsChild(parentView);
                                          

                                          Basically, I've created my own GTK window, passed the reference on this window to CEF, and placed it into Qt widget using QWindow::fromWinId().

                                          T Offline
                                          T Offline
                                          Tomato Page
                                          wrote on last edited by
                                          #21

                                          @antofik
                                          Dear antofix,
                                          Could you send me a complete example. I'm try the method but still not working with qt 5.5

                                          thanks

                                          1 Reply Last reply
                                          0

                                          • Login

                                          • Login or register to search.
                                          • First post
                                            Last post
                                          0
                                          • Categories
                                          • Recent
                                          • Tags
                                          • Popular
                                          • Users
                                          • Groups
                                          • Search
                                          • Get Qt Extensions
                                          • Unsolved