CEF3 on win32 + gtk

[PolesApart]

Hi,

I'm currently integrating cef3 in an existing application written in gtk3 on win32 (yes, I know ...).
It's actually working pretty well, except for quite a high cpu usage on idle, because gtk runs on the main thread and I had to add a g_idle_add() call to a function that periodically calls CefDoMessageLoopWork().

I tried using CefRunMessageLoop approach but couldn't figure out a way to integrate gtk to it's message system.

I also tried leaving the gtk event loop on main thread and setting settings.multi_threaded_message_loop = 1 before CefInitialize, but cef won't render then.

The multithread approach IMHO would be better as this app may run on battery powered devices, I'd rather have threads sleeping when nothing is being done than have a polling of some sort.

Any thoughts?

[magreenblatt]

What CEF3 version? Are you using windowed or off-screen rendering?

[PolesApart]

I made multithreaded message loop work. I started my coding using an example that used CreateBrowserSync instead of CreateBrowser (btw I couldn't figure out the difference between then). I've just changed to the latter, removed the g_idle_add hook that called CefDoMessageLoopWork, and it's working as a breeze now.
I'm using 3.2171.1949 on windows32, with windowed rendering.

The code I've used to hook a GtkDrawingArea to cef was this, if anyone else is crazy enough to run a gtk app on windows:

Code: Select all

static void setAsChild(GtkWidget *widget, CefWindowInfo &info) {
  gtk_widget_realize(widget);
  GdkWindow *gdk_window = gtk_widget_get_window(GTK_WIDGET(widget));
  if (!gdk_window_ensure_native(gdk_window)) {
    g_error("gdk_window_ensure_native failed...");
  }
  HWND hWnd = gdk_win32_window_get_impl_hwnd(gdk_window);
  RECT rect;
  printf("rect: %ld %ld %ld %ld\n", rect.bottom, rect.left, rect.right, rect.top);
  GetClientRect(hWnd, &rect);
  info.SetAsChild(hWnd, rect);
}

This is the callback to inform cef's window that the widget was resized:

Code: Select all

extern "C" {

  void __declspec(dllexport) on_area_size_allocate(GtkWidget *widget,
          GdkRectangle *allocation,
          gpointer user_data) {
    CefRefPtr<CefBrowser> browser = NULL;
    if (g_handler) {
      browser = g_handler->GetBrowser();
    }
    if (browser) {
      HWND hWnd = browser->GetHost()->GetWindowHandle();
      HDWP hdwp = BeginDeferWindowPos(1);
      hdwp = DeferWindowPos(hdwp, hWnd, NULL, 0, 0,
              allocation->width, allocation->height, SWP_NOZORDER);
      EndDeferWindowPos(hdwp);
    } else {
      // At least the first time gtk generates this event, there's no native window realized.
      // It'll call it again with a realized window and we catch that then.
      //printf("Had no window to hook to.\n");
    }
  }
}


[magreenblatt]

If you're moving only a single window you can just use SetWindowPos instead of the defer functions.

[PolesApart]

If you're moving only a single window you can just use SetWindowPos instead of the defer functions.

Thanks!