QPainter :: begin：绘制设备返回的引擎== 0，键入：2

Question

我正在尝试打印Qtablewidget，但它只打印空白页，并且显示应用程序输出

QPrinter::metric: Invalid metric command
QPainter::begin: Paint device returned engine == 0, type: 2
QWidget::render: Cannot render with an inactive painter

打印功能

void MainWindow::on_btPrint_clicked(){
  QPrinter printer(QPrinter::HighResolution);
  QPrintDialog printer_dialog(&printer, this);
  if (printer_dialog.exec() == QDialog::Rejected) return;
  QPainter painter(&printer);
  ui->table_log->render(&painter);
}

Answer 1

由设置的painter.scale固定

double xscale = printer.pageRect().width()/double(ui->table_log->width());
double yscale = printer.pageRect().height()/double(ui->table_log->height());
double scale = qMin(xscale, yscale);
painter.scale(scale, scale);

打印小部件