C++ (Qt)
#include <QtGui/QApplication>
#include <QtGui/QPrinter>
#include <QtGui/QPainter>
#include <QtGui/QPaintEngine>
#include <QtGui/QTextItem>
#include <QtGui/QFont>
#include <QtGui/QPrinterInfo>
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
 
    QPrinter printer(QPrinter::HighResolution);
    QPainter painter(&printer);
    printer.setPrinterName(QPrinterInfo::defaultPrinter().printerName());
    printer.setResolution(QPrinter::HighResolution);
    printer.setOutputFormat(QPrinter::NativeFormat);
    printer.setOrientation(QPrinter::Portrait);
    printer.setPageSize(QPrinter::A4);
    printer.setPaperSize(QPrinter::A4);
 
    printer.setPaperSize(QSize(210,297),QPrinter::Millimeter);
    qDebug(qPrintable("Page Rect Width "+QString::number(printer.pageRect().width())+
                      " Height "+QString::number(printer.pageRect().height())));
    qDebug(qPrintable("Paper size in mm: Width "+QString::number(printer.paperSize(QPrinter::Millimeter).width())+
                      " Height "+QString::number(printer.paperSize(QPrinter::Millimeter).height())));
    qDebug(qPrintable("Paper Size in device: Width "+QString::number(printer.paperSize(QPrinter::DevicePixel).width())+
                      " Height "+QString::number(printer.paperSize(QPrinter::DevicePixel).height())));
 
    qDebug(qPrintable("Paper Size in 1/72 inhc: Width "+QString::number(printer.paperSize(QPrinter::Point).width())+
                      " Height "+QString::number(printer.paperSize(QPrinter::Point).height())));
    qDebug(qPrintable("Painter size: Width "+QString::number(printer.widthMM())+
                      " Height "+QString::number(printer.widthMM())));
 
    qDebug(qPrintable("Logical Resolution: X "+QString::number(printer.logicalDpiX())+
                      " Y "+QString::number(printer.logicalDpiY())));
    qDebug(qPrintable("Phisical Resolution: X "+QString::number(printer.physicalDpiX())+
                      " Y "+QString::number(printer.physicalDpiY())));
 
     painter.setRenderHint(QPainter::Antialiasing);
 
     QRect paperRect(0,0,printer.paperSize(QPrinter::DevicePixel).width(),printer.paperSize(QPrinter::DevicePixel).height());
     double dpiX = painter.paintEngine()->paintDevice()->logicalDpiX();
     double dpiY = painter.paintEngine()->paintDevice()->logicalDpiY();
     double m = (2.0/2.54)*printer.logicalDpiX();
 
     QFont *font = new QFont("Courier New");
 
     dpiX = printer.logicalDpiX();
     dpiY = printer.logicalDpiY();
 
     font->setPixelSize(dpiY*3/25.4); //24  //30   //38
     font->setFixedPitch(true);
     font->setBold(true);
     font->setKerning(true);
     font->setLetterSpacing(QFont::AbsoluteSpacing, dpiY*4/25.4 /*19.5*/); //17.5  //13.5  //8.5
 
     painter.drawText(QPointF(dpiX*47/25.4, dpiY*21/25.4),"PRINT TEST");
 
     QPen pen;
     pen.setWidth(2);
     painter.setPen(pen);
 
     painter.drawLine(QPointF(dpiX*45/25.4,dpiY*19/25.4),QPointF(dpiX*260/25.4,dpiY*19/25.4));
     painter.drawLine(QPointF(dpiX*45/25.4,dpiY*24/25.4),QPointF(dpiX*260/25.4,dpiY*24/25.4));
 
 
     double d = 45;
     for(int i=0; i<38; ++i){
        painter.drawLine(QPointF(dpiX*(45+d*i)/25.4,dpiY*19/25.4),QPointF(dpiX*(45+d*i)/25.4,dpiY*24/25.4));
     }
 
     painter.drawLine(QPointF(dpiX*45/25.4,dpiY*26/25.4),QPointF(dpiX*260/25.4,dpiY*26/25.4));
     painter.drawLine(QPointF(dpiX*45/25.4,dpiY*31/25.4),QPointF(dpiX*260/25.4,dpiY*31/25.4));
 
     d = 45;
     for(int i=0; i<38; ++i){
        painter.drawLine(QPointF(dpiX*(45+d*i)/25.4,dpiY*19/25.4),QPointF(dpiX*(45+d*i)/25.4,dpiY*24/25.4));
     }
     painter.end();
    return a.exec();
}