WebEngine Widgets Html2Pdf Example▲
Html2Pdf demonstrates how to use Qt WebEngine to implement a command-line application for converting web pages into PDF documents.
Running the Example▲
To run the example from http://, open the Welcome mode and select the example from Examples. For more information, visit http://.
The Conversion Process▲
In order to convert a web page into a PDF document we need to:
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Create a https://.
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Tell the https:// to begin loading the target URL and wait for it to finish.
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Tell the https:// to begin converting the loaded page into a PDF file and again wait for it to finish.
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Once the conversion is finished, exit the program.
This process is encapsulated in the Html2PdfConverter class:
#include <QApplication>
#include <QCommandLineParser>
#include <QFile>
#include <QTextStream>
#include <QWebEnginePage>
#include <functional>
using namespace std;
using namespace std::placeholders;
class Html2PdfConverter : public QObject
{
Q_OBJECT
public:
explicit Html2PdfConverter(QString inputPath, QString outputPath);
int run();
private slots:
void loadFinished(bool ok);
void pdfPrintingFinished(const QString &filePath, bool success);
private:
QString m_inputPath;
QString m_outputPath;
QScopedPointer<QWebEnginePage> m_page;
};In the constructor we create the https:// and connect to its https:// and https:// signals:
Html2PdfConverter::Html2PdfConverter(QString inputPath, QString outputPath)
: m_inputPath(move(inputPath))
, m_outputPath(move(outputPath))
, m_page(new QWebEnginePage)
{
connect(m_page.data(), &QWebEnginePage::loadFinished,
this, &Html2PdfConverter::loadFinished);
connect(m_page.data(), &QWebEnginePage::pdfPrintingFinished,
this, &Html2PdfConverter::pdfPrintingFinished);
}The run() method will trigger the conversion process by asking https:// to start loading the target URL. We then enter the main event loop:
int Html2PdfConverter::run()
{
m_page->load(QUrl::fromUserInput(m_inputPath));
return QApplication::exec();
}After the loading is finished we begin PDF generation. We ask the https:// method to write the output directly to disk:
void Html2PdfConverter::loadFinished(bool ok)
{
if (!ok) {
QTextStream(stderr)
<< tr("failed to load URL '%1'").arg(m_inputPath) << "\n";
QCoreApplication::exit(1);
return;
}
m_page->printToPdf(m_outputPath);
}Once we receive the signal that the PDF conversion has finished, all that remains is to report potential errors and exit the program:
void Html2PdfConverter::pdfPrintingFinished(const QString &filePath, bool success)
{
if (!success) {
QTextStream(stderr)
<< tr("failed to print to output file '%1'").arg(filePath) << "\n";
QCoreApplication::exit(1);
} else {
QCoreApplication::quit();
}
}The Main Function▲
Our main function is responsible for setting up a https:// and parsing command line arguments:
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QCoreApplication::setOrganizationName("QtExamples");
QCoreApplication::setApplicationName("html2pdf");
QCoreApplication::setApplicationVersion(QT_VERSION_STR);
QCommandLineParser parser;
parser.setApplicationDescription(
QCoreApplication::translate("main", "Converts the web page INPUT into the PDF file OUTPUT."));
parser.addHelpOption();
parser.addVersionOption();
parser.addPositionalArgument(
QCoreApplication::translate("main", "INPUT"),
QCoreApplication::translate("main", "Input URL for PDF conversion."));
parser.addPositionalArgument(
QCoreApplication::translate("main", "OUTPUT"),
QCoreApplication::translate("main", "Output file name for PDF conversion."));
parser.process(QCoreApplication::arguments());
const QStringList requiredArguments = parser.positionalArguments();
if (requiredArguments.size() != 2)
parser.showHelp(1);
Html2PdfConverter converter(requiredArguments.at(0), requiredArguments.at(1));
return converter.run();
}Note that to use Qt WebEngine Widgets we need to create a https:// and not a https://, even though this is a command line application.