[SOLVED] X error in 2623 when trying to set Qt win as parent

[Czarek]

What if you pass an invalid window handle?

From your first post:

Code: Select all

Window XCreateWindow(
    Display*      /* display */,
    Window      /* parent */,
    int         /* x */,                      // 0
    int         /* y */,                      // 0
    unsigned int   /* width */,               // 800
    unsigned int   /* height */,              // 600


What are the values for Window and Display*?

A bit late, but now we can see the crucial part of your code - how you create the window. I've looked at your C++ Qt example. You are embedding an external process non-qt control (CEF) directly inside the Qt Widget control. Did you ensure with the Qt documentation that you are allowed to do that? From what I know the QX11EmbedContainer control is designed for this.

[Czarek]

Also it looks like you are providing GtkWidget window handle, but CEF expects X11 window handle.

[Czarek]

One more thing. Sometimes bad code happens to work, same as bugs happen In regards to -> "it worked in earlier CEF, but now it stopped working - so it must be a CEF bug".

[romariorios]

What if you pass an invalid window handle?

Nothing happens. The window simply doesn't appear.

From your first post:

Code: Select all

Window XCreateWindow(
    Display*      /* display */,
    Window      /* parent */,
    int         /* x */,                      // 0
    int         /* y */,                      // 0
    unsigned int   /* width */,               // 800
    unsigned int   /* height */,              // 600


What are the values for Window and Display*?

I'd have to debug to it to know for sure. I'll try to verify that later.

A bit late, but now we can see the crucial part of your code - how you create the window. I've looked at your C++ Qt example. You are embedding an external process non-qt control (CEF) directly inside the Qt Widget control. Did you ensure with the Qt documentation that you are allowed to do that? From what I know the QX11EmbedContainer control is designed for this.

I might be wrong, but isn't this what cefclient does, basically? It just sets the Gtk Window as the parent with SetAsChild and doesn't do anything from the Gtk side.

In any case, QWidget::createWindowContainer can create a QWidget from an external window, but I think that's not a requirement for embedding windows inside Qt applications. (EDIT: I'll try to use it anyway, just in case)

Also it looks like you are providing GtkWidget window handle, but CEF expects X11 window handle.

No, I'm providing an X11 window handle. See: https://doc.qt.io/qt-5/qwidget.html#winId

One more thing. Sometimes bad code happens to work, same as bugs happen In regards to -> "it worked in earlier CEF, but now it stopped working - so it must be a CEF bug".

But I only assumed it was a CEF bug after testing the standard 2526 and 2623 builds (as mentioned in my previous post). Before that, I assumed it was some mistake emerging from the customizations I did to CEF and cefsimple.

[Czarek]

Also it looks like you are providing GtkWidget window handle, but CEF expects X11 window handle.

No, I'm providing an X11 window handle. See: https://doc.qt.io/qt-5/qwidget.html#winId

I have twisted that sentence around. It should be - winId() returns X11 window handle, but CEF expects GtkWidget pointer. This was true as of CEF branch 1650. But I recall there were some changes in later CEF versions to allow embedding using x11 handle as well.

Just use QX11EmbedContainer and it should work.

[romariorios]

I have twisted that sentence around. It should be - winId() returns X11 window handle, but CEF expects GtkWidget pointer.

I'm pretty sure this isn't the case anymore. For example, cefclient/browser/browser_window_std_gtk.cc, line 98:

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  CefWindowInfo window_info;
  window_info.SetAsChild(GetXWindowForWidget(parent_handle), rect);


The GetXWindowForWidget() function returns an X11 Window, as you can see from line 23:

Code: Select all

::Window GetXWindowForWidget(GtkWidget* widget) {


Just use QX11EmbedContainer and it should work.

That's a Qt4 class. Qt5's equivalent would probably be QWidget::createWindowContainer() and QWindow::fromWinId(), but I need to get cefsimple's winId first. Any idea on how to do that? (EDIT: actually, nevermind that, I think I got it).

[Czarek]

See http://stackoverflow.com/questions/3270 ... 6#32705686

[romariorios]

See http://stackoverflow.com/questions/3270 ... 6#32705686

Thanks. Based on that, here's what I tried:

Code: Select all

#include <QApplication>

#include <QDebug>

#include <QWidget>
#include <QWindow>

int main(int argc, char *argv[])
{
  QApplication a(argc, argv);

  QWidget w;
  auto wId = w.winId();
  auto subW = QWindow::fromWinId(wId);
  auto container = QWidget::createWindowContainer(subW);

  w.show();

  qDebug() << "WinID:" << container->winId();

  return a.exec();
}


Then I call SetAsChild with that winId from the cefsimple side. It still doesn't work.

By comparison, I made a similar Qt 4 application using QX11EmbedContainer:

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#include <QApplication>

#include <QDebug>

#include <QX11EmbedContainer>

int main(int argc, char *argv[])
{
  QApplication a(argc, argv);

  QX11EmbedContainer container;
  container.resize(800, 600);
  container.show();

  qDebug() << "WinID:" << container.winId();

  return a.exec();
}


Works just fine. But I can't use Qt 4, unfortunately.

Any ideas on how to do that properly with Qt 5?

[Czarek]

Are you using the latest Qt 5.5 stable? Print "wId" for debug info. Call subW.show() and container.show() as well - currently only w.show() is called.

[romariorios]

Are you using the latest Qt 5.5 stable?

Yup

Print "wId" for debug info. Call subW.show() and container.show() as well - currently only w.show() is called.

Okay, here's the modified version:

Code: Select all

#include <QApplication>

#include <QDebug>

#include <QWidget>
#include <QWindow>

int main(int argc, char *argv[])
{
  QApplication a(argc, argv);

  QWidget w;
  auto wId = w.winId();
  auto subW = QWindow::fromWinId(wId);
  auto container = QWidget::createWindowContainer(subW);

  w.show();
  subW->show();
  container->show();

  qDebug() << "Widget WId:" << wId;
  qDebug() << "Sub-win WId:" << subW->winId();
  qDebug() << "Container WId:" << container->winId();

  return a.exec();
}


It prints out:

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Widget WId: 96468996
Sub-win WId: 96468996
Container WId: 96469003


I passed both IDs to SetAsChild with no success, no window is shown -- still works with 2526.