QPrinter without QPrintDialog

[jefftee]

Hi, I'm trying to print directly to a QPrinter that I constructed without using QPrintDialog. If I use QPrintDialog, the page prints as expected, however, when I don't use QPrintDialog, the printed page on my Canon PIXMA Pro-100 inkjet printer comes out extremely small. The same code works OK if I print to a different printer, so the problem seems to be specific to my Canon inkjet printer!

Here's the QPrinter initialization code that I'm using:

QPrinter printer_(QPrinter::HighResolution);
printer_.setPrinterName("Canon_PRO_100_series");
printer_.setResolution(300);
printer_.setPageLayout(page_layout);
printer_.setCopyCount(1);
printer_.setDoubleSidedPrinting(false);
printer_.setDuplex(QPrinter::DuplexNone);
printer_.setColorMode(QPrinter::Color);
printer_.setPageSize(QPrinter::Letter);
printer_.setPaperSize(QPrinter::Letter);
printer_.setPaperSource(QPrinter::Auto);
printer_.setCreator("Inkjet Plumber");
printer_.setOrientation(QPrinter::Portrait);
printer_.setPageMargins(.5, .5, .5, .5, QPrinter::Inch);
printer_.setPageLayout(page_layout);
printer_.setDocName("Inkjet Plumber Maintenance Job");
//    printer_.setOutputFileName("/Users/jefft/Downloads/ijp.pdf");
//    printer_.setOutputFormat(QPrinter::PdfFormat);
printer_.setOutputFormat(QPrinter::NativeFormat);
 
if (!printer_.isValid())
    qDebug("Printer is invalid!");

QPrinter printer_(QPrinter::HighResolution);
printer_.setPrinterName("Canon_PRO_100_series");
printer_.setResolution(300);
printer_.setPageLayout(page_layout);
printer_.setCopyCount(1);
printer_.setDoubleSidedPrinting(false);
printer_.setDuplex(QPrinter::DuplexNone);
printer_.setColorMode(QPrinter::Color);
printer_.setPageSize(QPrinter::Letter);
printer_.setPaperSize(QPrinter::Letter);
printer_.setPaperSource(QPrinter::Auto);
printer_.setCreator("Inkjet Plumber");
printer_.setOrientation(QPrinter::Portrait);
printer_.setPageMargins(.5, .5, .5, .5, QPrinter::Inch);
printer_.setPageLayout(page_layout);
printer_.setDocName("Inkjet Plumber Maintenance Job");
//    printer_.setOutputFileName("/Users/jefft/Downloads/ijp.pdf");
//    printer_.setOutputFormat(QPrinter::PdfFormat);
printer_.setOutputFormat(QPrinter::NativeFormat);

if (!printer_.isValid())
    qDebug("Printer is invalid!");

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If I uncomment lines 16-17 and print to PDF, the PDF file looks as expected and prints fine using the Mac Preview app. The code I use to render the page is:

void MainWindow::paint_page(QPrinter *printer)
{
    QPainter painter;
 
    painter.begin(printer);
 
    painter.setRenderHint(QPainter::Antialiasing);
    painter.setPen(Qt::black);
//  Draw page rect to show printable page (excluding margins)
//  painter.drawRect(painter_rect);
    painter.setFont(QFont("Tahoma", 10));
    painter.drawText(0, 0, "Inkjet Plumber maintenance job sent to " + printer_info_.printerName() + ": " + QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss."));
    painter.setPen(QPen(Qt::black));
    print_swatch(painter, 0, 50, Qt::cyan);
    print_swatch(painter, 200, 50, Qt::magenta);
    print_swatch(painter, 400, 50, Qt::yellow);
    print_swatch(painter, 600, 50, Qt::black);
    print_swatch(painter, 800, 50, Qt::gray);
    print_swatch(painter, 1000, 50, Qt::lightGray);
    print_swatch(painter, 1200, 50, Qt::red);
    print_swatch(painter, 1400, 50, Qt::green);
    print_swatch(painter, 1600, 50, Qt::blue);
 
    painter.end();
 
    return;
}

void MainWindow::paint_page(QPrinter *printer)
{
    QPainter painter;
    
    painter.begin(printer);

    painter.setRenderHint(QPainter::Antialiasing);
    painter.setPen(Qt::black);
//  Draw page rect to show printable page (excluding margins)
//  painter.drawRect(painter_rect);
    painter.setFont(QFont("Tahoma", 10));
    painter.drawText(0, 0, "Inkjet Plumber maintenance job sent to " + printer_info_.printerName() + ": " + QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss."));
    painter.setPen(QPen(Qt::black));
    print_swatch(painter, 0, 50, Qt::cyan);
    print_swatch(painter, 200, 50, Qt::magenta);
    print_swatch(painter, 400, 50, Qt::yellow);
    print_swatch(painter, 600, 50, Qt::black);
    print_swatch(painter, 800, 50, Qt::gray);
    print_swatch(painter, 1000, 50, Qt::lightGray);
    print_swatch(painter, 1200, 50, Qt::red);
    print_swatch(painter, 1400, 50, Qt::green);
    print_swatch(painter, 1600, 50, Qt::blue);

    painter.end();

    return;
}

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Here's the print preview code that works fine and prints fine if I print using the QPrintPreviewDialog:

QPrintPreviewDialog preview_dlg(&printer_);
connect(&preview_dlg, &QPrintPreviewDialog::paintRequested, this, &MainWindow::paint_page);
int result = preview_dlg.exec();

QPrintPreviewDialog preview_dlg(&printer_);
connect(&preview_dlg, &QPrintPreviewDialog::paintRequested, this, &MainWindow::paint_page);
int result = preview_dlg.exec();

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and finally the QPrintDialog snippet that works fine as well, but this program is a utility that I need to print w/o user intervention, so the QPrintDialog isn't really an option:

QPrintDialog print_dlg(&printer_);
result = print_dlg.exec();
if (result == true)
    paint_page(&printer_);

QPrintDialog print_dlg(&printer_);
result = print_dlg.exec();
if (result == true)
    paint_page(&printer_);

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Needless to say, this is driving me bonkers! Can anyone see why I might be having an issue printing without using QPrintDialog?

Thanks,

jefftee