[QT] Print widget && Save widget to image file

1.Print QWidget

 QPrinter printer(QPrinter::ScreenResolution);
 QPrintDialog *dialog = new QPrintDialog(&printer, this);
 dialog->setWindowTitle(tr("Print Document"));
 
 if (dialog->exec() != QDialog::Accepted)
  return;

 QPainter painter;
 QPixmap pix = QPixmap::grabWidget(ui.tabWidget->currentWidget());
 painter.begin(&printer);
 painter.drawPixmap(0,0,pix);
 painter.end();

2.Save QWidget to image file

QPixmap pix;
pix = QPixmap::grabWidget(ui.tabWidget->currentWidget());

 QString fileName = QFileDialog::getSaveFileName(this, tr("Save File"),"",tr("Images(*.jpg)"));

 if(!fileName.isEmpty()) {  
  if(!pix.save(fileName,"JPG",100)) {
   QMessageBox::warning(this,tr("Error"),tr("Can not save image file!"));
  }else {
   QMessageBox::information(this,tr("Info"),tr("Save OK."));
  }
 }