int main(int argc, char *argv[])
{ 
  QApplication a(argc, argv); 
  QWidget* mw = new QWidget(); 
  mw->setFixedSize(800, 600); 
  QWidget* canvas = new QWidget(mw); 
  canvas->setGeometry(0, 0, 800, 600); 
  canvas->setStyleSheet("background-color:red"); 
  NSView* remote = [[NSView alloc] initWithFrame:CGRectMake(0, 0, 1, 1)]; 
  [remote setWantsLayer:true]; remote.layer.backgroundColor = [NSColor yellowColor].CGColor; 
  NSView* cv = reinterpret_cast<NSView*>(canvas->winId()); 
  [cv addSubview:remote]; 
  [remote setTranslatesAutoresizingMaskIntoConstraints:NO];       
  [remote.bottomAnchor constraintEqualToAnchor:cv.bottomAnchor constant:0.0f].active = YES; 
  [remote.leadingAnchor constraintEqualToAnchor:cv.leadingAnchor constant:50.0f].active = YES; 
  [remote.widthAnchor constraintEqualToAnchor:cv.widthAnchor multiplier:1.0f constant:0.0f].active = YES; 
  [remote.heightAnchor constraintEqualToAnchor:cv.heightAnchor multiplier:1.0f constant:0.0f].active = YES; 
  QWidget* tool = new QWidget(mw); 
  tool->setGeometry(0, 400, 800, 600); 
  tool->setStyleSheet("background-color:green"); mw->show(); 
  return a.exec(); 
}