How to display PDF in Qt?

**patrik08** · 19th May 2008, 06:52

Originally Posted by stelio

Hi!

is there any ways to display PDF in an Qt application?

Thanks!
stelio

QT3 DTP Scribus programm import pdf as image .. need only ghostscript an run on mac,win, linux

this is part of code from QT 4.4 MiniScribus
http://www.qt-apps.org/content/show....?content=80234

Qt Code:

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extern inline QPixmap LoadPDF(QString fn, int Page, int w )
{
	QString tmp, cmd1, cmd2;
	const QString pdfFile = PathConvert(fn);
	const QString tmpFile = PathConvert(QDir::homePath()+"/sctodaytmps.png");
    const QString qttmpFile = QDir::homePath()+"/sctodaytmps.png";
	QPixmap pm;
    tmp.setNum(Page);
	int ret = -1;
	tmp.setNum(Page);
	QStringList args;
    args.append("-sDEVICE=png16m");
    args.append("-r72");
    args.append("-dGraphicsAlphaBits=4");
    args.append("-o");
	args.append(tmpFile);
    args.append("-dFirstPage="+tmp);
	args.append("-dLastPage="+tmp);
	args.append(pdfFile);
	ret = callGS(args);
    ////////qDebug() << "### ret " << ret;
	if (ret == 0)
	{
		QPixmap tmpimage(qttmpFile);
        QPixmap penna = tmpimage.scaledToWidth(w);
        tmpimage.detach(); 
        QFile lastaction(qttmpFile);
        lastaction.remove();
        QPainter p;
		p.begin(&penna);
		p.setBrush(Qt::NoBrush);
		p.setPen(QPen(QBrush(Qt::black),2,Qt::SolidLine));
		p.drawRect(0, 0, penna.width(), penna.height());
		p.end();
        return penna;
	}
	return pm;
}
 
extern inline int callGS( const QStringList args )
{
   const QString startnow = QDir::currentPath();
   const QString GhostScriptPath = getGSDefaultExeName();
   QDir::setCurrent(_GSCACHE_);
   QString  cmd1 =  GhostScriptPath + " ";
   cmd1 += args.join(" ");
   int fax = -1;
   #if defined Q_WS_MAC
   fax = system(cmd1.toLocal8Bit());
   QDir::setCurrent(startnow);
   return fax;
   #endif
   QProcess *process = new QProcess(NULL);
   process->setReadChannelMode(QProcess::MergedChannels);
   process->start( GhostScriptPath ,  args , QIODevice::ReadOnly );
          if (!process->waitForFinished()) {
           fax = -1;
          } else {
            QString ghostcomment = process->readAll().trimmed();
            //////qDebug() << "ghostcomment-> " << ghostcomment; 
            fax = 0;
          }
 
   QDir::setCurrent(startnow);
   return fax;
}

extern inline QPixmap LoadPDF(QString fn, int Page, int w )
{
	QString tmp, cmd1, cmd2;
	const QString pdfFile = PathConvert(fn);
	const QString tmpFile = PathConvert(QDir::homePath()+"/sctodaytmps.png");
    const QString qttmpFile = QDir::homePath()+"/sctodaytmps.png";
	QPixmap pm;
    tmp.setNum(Page);
	int ret = -1;
	tmp.setNum(Page);
	QStringList args;
    args.append("-sDEVICE=png16m");
    args.append("-r72");
    args.append("-dGraphicsAlphaBits=4");
    args.append("-o");
	args.append(tmpFile);
    args.append("-dFirstPage="+tmp);
	args.append("-dLastPage="+tmp);
	args.append(pdfFile);
	ret = callGS(args);
    ////////qDebug() << "### ret " << ret;
	if (ret == 0)
	{
		QPixmap tmpimage(qttmpFile);
        QPixmap penna = tmpimage.scaledToWidth(w);
        tmpimage.detach(); 
        QFile lastaction(qttmpFile);
        lastaction.remove();
        QPainter p;
		p.begin(&penna);
		p.setBrush(Qt::NoBrush);
		p.setPen(QPen(QBrush(Qt::black),2,Qt::SolidLine));
		p.drawRect(0, 0, penna.width(), penna.height());
		p.end();
        return penna;
	}
	return pm;
}

extern inline int callGS( const QStringList args )
{
   const QString startnow = QDir::currentPath();
   const QString GhostScriptPath = getGSDefaultExeName();
   QDir::setCurrent(_GSCACHE_);
   QString  cmd1 =  GhostScriptPath + " ";
   cmd1 += args.join(" ");
   int fax = -1;
   #if defined Q_WS_MAC
   fax = system(cmd1.toLocal8Bit());
   QDir::setCurrent(startnow);
   return fax;
   #endif
   QProcess *process = new QProcess(NULL);
   process->setReadChannelMode(QProcess::MergedChannels);
   process->start( GhostScriptPath ,  args , QIODevice::ReadOnly );
          if (!process->waitForFinished()) {
           fax = -1;
          } else {
            QString ghostcomment = process->readAll().trimmed();
            //////qDebug() << "ghostcomment-> " << ghostcomment; 
            fax = 0;
          }
          
   QDir::setCurrent(startnow);
   return fax;
}

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**stelio** · 19th May 2008, 09:15

Thanks for all those answers!

I will investigate xpdf, mupdf and poppler to better understand.

MiniScribus is very interesting, but as I understand, it convert it to a png. I need to provide graphical zoom feature in the PDF without loosing the vectorial display.

Is converting PDF to SVG an option?

stelio