Qt 5.11 | Qt Widgets | Image Gestures Example | main.cpp Example File

Qt 5.11.3 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();
      }