The GUI is hang

[wysota]

Show your main() please.

[ugiwgh]

The following is my main code.

int main(int argc,char **argv)
{
  qDebug()<<"Main Begin";
  QApplication app(argc,argv);
 
  MCanvas *canvas=new MCanvas;
  MRender *render=new MRender;
  MZoom *zoom=new MZoom;
  //if(NULL==zoom)qDebug()<<"zomm is null";
  //QObject::connect(render,SIGNAL(rendered(const QImage &)),canvas,SLOT(updateImage(const QImage &)));
  QObject::connect(render,SIGNAL(rendered(const QImage &)),canvas,SLOT(updateImage(const QImage &)),Qt::DirectConnection);  // This is the hang line
  render->start();
  zoom->start();
 
  QWidget *widget=new QWidget;
  widget->resize(800,600);
  QGridLayout *layout=new QGridLayout(widget);
  layout->addWidget(canvas);
  layout->setContentsMargins(0,0,0,0);
  widget->setLayout(layout);
  widget->show();
 
  app.exec();
  delete render;
  delete widget;
  qDebug()<<"Main End";
 
  return 0;
}

int main(int argc,char **argv)
{
  qDebug()<<"Main Begin";
  QApplication app(argc,argv);

  MCanvas *canvas=new MCanvas;
  MRender *render=new MRender;
  MZoom *zoom=new MZoom;
  //if(NULL==zoom)qDebug()<<"zomm is null";
  //QObject::connect(render,SIGNAL(rendered(const QImage &)),canvas,SLOT(updateImage(const QImage &)));
  QObject::connect(render,SIGNAL(rendered(const QImage &)),canvas,SLOT(updateImage(const QImage &)),Qt::DirectConnection);  // This is the hang line
  render->start();
  zoom->start();

  QWidget *widget=new QWidget;
  widget->resize(800,600);
  QGridLayout *layout=new QGridLayout(widget);
  layout->addWidget(canvas);
  layout->setContentsMargins(0,0,0,0);
  widget->setLayout(layout);
  widget->show();

  app.exec();
  delete render;
  delete widget;
  qDebug()<<"Main End";

  return 0;
}

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[anda_skoa]

As wysota already told you in the other thread (btw, thanks for duplicating the topic), you cannot create a QPixmap in any other thread then the one running the QApplication event loop (here the main thread).

Cheers,
_

[ugiwgh]

As wysota already told you in the other thread (btw, thanks for duplicating the topic), you cannot create a QPixmap in any other thread then the one running the QApplication event loop (here the main thread).

Thanks for your attention.
This is the different with that thread.
My code has been improved for many times. And some problems are resolved, some new problems come in.
I had removed QPixmap from any other thread.

[wysota]

Please prepare a minimal compilable example reproducing the problem.

[ugiwgh]

Sorry, it worksforme.
It happend when I add "zoomMessage_="Who am I?";" to class MZoom constructor.
And I don't have enough information to reproduce it now too.
I ask redhat in the following link https://bugzilla.redhat.com/show_bug.cgi?id=1160557.