main.cpp Example File | Qt Widgets 5.12.12

- Qt 5.12
- Qt Widgets
- Image Gestures Example
- main.cpp Example File
- Qt 5.12.12 Reference Documentation

# main.cpp Example File

gestures/imagegestures/main.cpp

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     #include <QtWidgets>

     #include "mainwidget.h"

     static void showHelp(QCommandLineParser &parser, const QString errorMessage = QString())
     {
         QString text;
         QTextStream str(&text);
         str << "<html><head/><body>";
         if (!errorMessage.isEmpty())
             str << "<p>" << errorMessage << "</p>";
         str << "<pre>" << parser.helpText() << "</pre></body></html>";
         QMessageBox box(errorMessage.isEmpty() ? QMessageBox::Information : QMessageBox::Warning,
                         QGuiApplication::applicationDisplayName(), text,
                         QMessageBox::Ok);
         box.setTextInteractionFlags(Qt::TextBrowserInteraction);
         box.exec();
     }

     int main(int argc, char *argv[])
     {
         QApplication app(argc, argv);
         QCoreApplication::setApplicationVersion(QT_VERSION_STR);
         QCoreApplication::setApplicationName(QStringLiteral("imagegestures"));
         QGuiApplication::setApplicationDisplayName(QStringLiteral("Image Gestures Example"));

         QCommandLineParser commandLineParser;
         const QCommandLineOption disablePanOption("no-pan", "Disable pan gesture");
         commandLineParser.addOption(disablePanOption);
         const QCommandLineOption disablePinchOption("no-pinch", "Disable pinch gesture");
         commandLineParser.addOption(disablePinchOption);
         const QCommandLineOption disableSwipeOption("no-swipe", "Disable swipe gesture");
         commandLineParser.addOption(disableSwipeOption);
         const QCommandLineOption helpOption = commandLineParser.addHelpOption();
         commandLineParser.addPositionalArgument(QStringLiteral("Directory"),
                                                 QStringLiteral("Directory to display"));

         const QString description = QGuiApplication::applicationDisplayName()
             + QLatin1String("\n\nEnable \"debug\" on the logging category \"qt.examples.imagegestures\" in order to\n"
                             "in order to obtain verbose information about Qt's gesture event processing,\n"
                             "for example by setting the environment variables QT_LOGGING_RULES to\n"
                             "qt.examples.imagegestures.debug=true\n");
         commandLineParser.setApplicationDescription(description);

         commandLineParser.process(QCoreApplication::arguments());

         QStringList arguments = commandLineParser.positionalArguments();
         if (!arguments.isEmpty() && !QFileInfo(arguments.front()).isDir()) {
             showHelp(commandLineParser,
                      QLatin1Char('"') + QDir::toNativeSeparators(arguments.front())
                      + QStringLiteral("\" is not a directory."));
             return -1;
         }

         QList<Qt::GestureType> gestures;
         if (!commandLineParser.isSet(disablePanOption))
             gestures << Qt::PanGesture;
         if (!commandLineParser.isSet(disablePinchOption))
             gestures << Qt::PinchGesture;
         if (!commandLineParser.isSet(disableSwipeOption))
             gestures << Qt::SwipeGesture;

         MainWidget w;
         w.grabGestures(gestures);
         w.show();

         if (arguments.isEmpty()) {
             const QStringList picturesLocations = QStandardPaths::standardLocations(QStandardPaths::PicturesLocation);
             const QString directory =
                 QFileDialog::getExistingDirectory(&w, "Select image folder",
                                                   picturesLocations.isEmpty() ? QString() : picturesLocations.front());
             if (directory.isEmpty())
                 return 0;
             arguments.append(directory);
         }

         w.openDirectory(arguments.front());

         return app.exec();
     }