QPrinter & QPainter render() problem

[Mannion]

I have a problem when calling Qwidget::render() on a specific printer connected via a network to a PC running XP. I am quite new to using the Qprinter class so I apologise if I am missing something obvious. I get a repeatable crash when rendering to the printer in question. The only diffreence I can see between the working printers and the crashing one is the printer resolution. I seem to get the problem no matter what I render. The crash always seesm to occur at the render() call.

Here is attached example code:

void MainWindow::menuPrintTest(){
    double xscale;  double yscale;  double scale;
    double printerWidth ;  double printerHeight ;
    double widgetWidth;  double widgetHeight ;
    QFont printFont("courier",  16);
    printFont.setFixedPitch(TRUE);
    QTextEdit *qteTestPrintRequest = new QTextEdit("",w);
    qteTestPrintRequest ->setFont(printFont );
    qteTestPrintRequest ->setFixedHeight(1750);
    qteTestPrintRequest ->setFixedWidth(1050);
    widgetWidth = qteTestPrintRequest ->width();
    widgetHeight = qteTestPrintRequest ->height();
 
    QString qsConcat = "Test Printout For Checking XP Print Request Bug\n";
    for (int i=0; i<30; i++){ qsConcat+= "Test Printout for Checking XP Print Request Bug\n" ; }
    qteTestPrintRequest->append( qsConcat );
 
    QPrinter printer(QPrinter::HighResolution);
    QString docName =   "Test Plot";
    if ( !docName.isEmpty())  {
        docName.replace (QRegExp (QString::fromLatin1 ("\n")), tr (" -- "));
        printer.setDocName (docName);
     }
     QPrintDialog dialog(&printer);
     if ( dialog.exec() )  {
        {
            {
                QPainter painter(&printer);
                printerWidth = printer.pageRect().width();
                printerHeight = printer.pageRect().height();
                xscale = printerWidth/(widgetWidth);
                yscale = printerHeight/(widgetHeight);
                scale = qMin(xscale, yscale);
                painter.scale(scale, scale);
                qteTestPrintRequest ->render(&painter);
            }
        }
    }
}

void MainWindow::menuPrintTest(){
    double xscale;  double yscale;  double scale;
    double printerWidth ;  double printerHeight ;
    double widgetWidth;  double widgetHeight ;
    QFont printFont("courier",  16);
    printFont.setFixedPitch(TRUE);
    QTextEdit *qteTestPrintRequest = new QTextEdit("",w);
    qteTestPrintRequest ->setFont(printFont );
    qteTestPrintRequest ->setFixedHeight(1750);
    qteTestPrintRequest ->setFixedWidth(1050);
    widgetWidth = qteTestPrintRequest ->width();
    widgetHeight = qteTestPrintRequest ->height();

    QString qsConcat = "Test Printout For Checking XP Print Request Bug\n";
    for (int i=0; i<30; i++){ qsConcat+= "Test Printout for Checking XP Print Request Bug\n" ; }
    qteTestPrintRequest->append( qsConcat );
    
    QPrinter printer(QPrinter::HighResolution);
    QString docName =   "Test Plot";
    if ( !docName.isEmpty())  {
        docName.replace (QRegExp (QString::fromLatin1 ("\n")), tr (" -- "));
        printer.setDocName (docName);
     }
     QPrintDialog dialog(&printer);
     if ( dialog.exec() )  {
        {
            {
                QPainter painter(&printer);
                printerWidth = printer.pageRect().width();
                printerHeight = printer.pageRect().height();
                xscale = printerWidth/(widgetWidth);
                yscale = printerHeight/(widgetHeight);
                scale = qMin(xscale, yscale);
                painter.scale(scale, scale);
                qteTestPrintRequest ->render(&painter);
            }
        }
    }
}

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The qDebug() output for the scaling is as follows:

printerWidth = 4908.0
printerHeight = 6408.0
widgetWidth = 1050.0
widgetHeight = 1750.0
xscale = 4.674
yscale = 3.662
scale = 3.662

As a matter of interest the output on one of the working printers is

printerWidth = 4760.0
printerHeight = 6814.0
widgetWidth = 1050.0
widgetHeight = 1750.0
xscale = 4.533
yscale = 3.894
scale = 3.894

[high_flyer]

Try printing something small - does it still crash then?
Also, you have a memory leak - you never delete 'qteTestPrintRequest' (but that should not play a role in the problem you have).

[Mannion]

Thankyou

I will try a print that is well within the pageRect() dimensions.

[Mannion]

I don't want to duplicate effort. My great thanks to all who have helped so far.

I hope that this is helpful to all concerned but this thread is being discussed in more detail on this link.

http://www.qtforum.org/article/37518...tml#post117656

[Mannion]

"I do need to rsolve this ASAP and would be willing to pay for a solution/resolution.":http://www.qtforum.org/article/37518...tml#post117656

The code above seems to work perfectly with all other configurations of Printer & PC tested. The problem seems to be that my simple test printout is generating a huge print document approximately a factor of 4000 times bigger (e.g. 213MB for a single A4 sheet) when sent to the specific printer involved:

Xerox Work Centre 7428 PS

The only potential leads I have are that it may be due to

1. A specific printer driver issue

2. QPrinter printer(QPrinter::HighResolution);
A guess.

3. qteTestPrintRequest->render(&painter);
Using render with a QTextEdit widget instead of using qteTestPrintRequest ->print(&printer);

4. Some other unidentified issue with the code posted above?

[wysota]

Maybe you should bother to answer high_flyer's question from post #2?