Qt 5.11 | Qt Widgets | Main Window | main.cpp Example File

Qt 5.11.3 Reference Documentation

# main.cpp Example File

mainwindows/mainwindow/main.cpp

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      #include "mainwindow.h"

      #include <QApplication>
      #include <QPainterPath>
      #include <QPainter>
      #include <QMap>
      #include <QDebug>

      void render_qt_text(QPainter *painter, int w, int h, const QColor &color)
      {
          QPainterPath path;
          path.moveTo(-0.083695, 0.283849);
          path.cubicTo(-0.049581, 0.349613, -0.012720, 0.397969, 0.026886, 0.428917);
          path.cubicTo(0.066493, 0.459865, 0.111593, 0.477595, 0.162186, 0.482108);
          path.lineTo(0.162186, 0.500000);
          path.cubicTo(0.115929, 0.498066, 0.066565, 0.487669, 0.014094, 0.468810);
          path.cubicTo(-0.038378, 0.449952, -0.088103, 0.423839, -0.135082, 0.390474);
          path.cubicTo(-0.182061, 0.357108, -0.222608, 0.321567, -0.256722, 0.283849);
          path.cubicTo(-0.304712, 0.262250, -0.342874, 0.239362, -0.371206, 0.215184);
          path.cubicTo(-0.411969, 0.179078, -0.443625, 0.134671, -0.466175, 0.081963);
          path.cubicTo(-0.488725, 0.029255, -0.500000, -0.033043, -0.500000, -0.104932);
          path.cubicTo(-0.500000, -0.218407, -0.467042, -0.312621, -0.401127, -0.387573);
          path.cubicTo(-0.335212, -0.462524, -0.255421, -0.500000, -0.161752, -0.500000);
          path.cubicTo(-0.072998, -0.500000, 0.003903, -0.462444, 0.068951, -0.387331);
          path.cubicTo(0.133998, -0.312218, 0.166522, -0.217440, 0.166522, -0.102998);
          path.cubicTo(0.166522, -0.010155, 0.143394, 0.071325, 0.097138, 0.141441);
          path.cubicTo(0.050882, 0.211557, -0.009396, 0.259026, -0.083695, 0.283849);
          path.moveTo(-0.167823, -0.456963);
          path.cubicTo(-0.228823, -0.456963, -0.277826, -0.432624, -0.314831, -0.383946);
          path.cubicTo(-0.361665, -0.323340, -0.385082, -0.230335, -0.385082, -0.104932);
          path.cubicTo(-0.385082, 0.017569, -0.361376, 0.112025, -0.313964, 0.178433);
          path.cubicTo(-0.277248, 0.229368, -0.228534, 0.254836, -0.167823, 0.254836);
          path.cubicTo(-0.105088, 0.254836, -0.054496, 0.229368, -0.016045, 0.178433);
          path.cubicTo(0.029055, 0.117827, 0.051605, 0.028691, 0.051605, -0.088975);
          path.cubicTo(0.051605, -0.179562, 0.039318, -0.255803, 0.014744, -0.317698);
          path.cubicTo(-0.004337, -0.365409, -0.029705, -0.400548, -0.061362, -0.423114);
          path.cubicTo(-0.093018, -0.445680, -0.128505, -0.456963, -0.167823, -0.456963);
          path.moveTo(0.379011, -0.404739);
          path.lineTo(0.379011, -0.236460);
          path.lineTo(0.486123, -0.236460);
          path.lineTo(0.486123, -0.197292);
          path.lineTo(0.379011, -0.197292);
          path.lineTo(0.379011, 0.134913);
          path.cubicTo(0.379011, 0.168117, 0.383276, 0.190442, 0.391804, 0.201886);
          path.cubicTo(0.400332, 0.213330, 0.411246, 0.219052, 0.424545, 0.219052);
          path.cubicTo(0.435531, 0.219052, 0.446227, 0.215264, 0.456635, 0.207689);
          path.cubicTo(0.467042, 0.200113, 0.474993, 0.188910, 0.480486, 0.174081);
          path.lineTo(0.500000, 0.174081);
          path.cubicTo(0.488436, 0.210509, 0.471957, 0.237911, 0.450564, 0.256286);
          path.cubicTo(0.429170, 0.274662, 0.407054, 0.283849, 0.384215, 0.283849);
          path.cubicTo(0.368893, 0.283849, 0.353859, 0.279094, 0.339115, 0.269584);
          path.cubicTo(0.324371, 0.260074, 0.313530, 0.246534, 0.306592, 0.228965);
          path.cubicTo(0.299653, 0.211396, 0.296184, 0.184075, 0.296184, 0.147002);
          path.lineTo(0.296184, -0.197292);
          path.lineTo(0.223330, -0.197292);
          path.lineTo(0.223330, -0.215667);
          path.cubicTo(0.241833, -0.224049, 0.260697, -0.237992, 0.279922, -0.257495);
          path.cubicTo(0.299147, -0.276999, 0.316276, -0.300129, 0.331310, -0.326886);
          path.cubicTo(0.338826, -0.341070, 0.349523, -0.367021, 0.363400, -0.404739);
          path.lineTo(0.379011, -0.404739);
          path.moveTo(-0.535993, 0.275629);

          painter->translate(w / 2, h / 2);
          double scale = qMin(w, h) * 8 / 10.0;
          painter->scale(scale, scale);

          painter->setRenderHint(QPainter::Antialiasing);

          painter->save();
          painter->translate(.1, .1);
          painter->fillPath(path, QColor(0, 0, 0, 63));
          painter->restore();

          painter->setBrush(color);
          painter->setPen(QPen(Qt::black, 0.02, Qt::SolidLine, Qt::FlatCap, Qt::RoundJoin));
          painter->drawPath(path);
      }

      static void usage()
      {
          qWarning() << "Usage: mainwindow [-SizeHint<color> <width>x<height>] ...";
          exit(1);
      }

      enum ParseCommandLineArgumentsResult {
          CommandLineArgumentsOk,
          CommandLineArgumentsError,
          HelpRequested
      };

      static ParseCommandLineArgumentsResult
          parseCustomSizeHints(const QStringList &arguments, MainWindow::CustomSizeHintMap *result)
      {
          result->clear();
          const int argumentCount = arguments.size();
          for (int i = 1; i < argumentCount; ++i) {
              const QString &arg = arguments.at(i);
              if (arg.startsWith(QLatin1String("-SizeHint"))) {
                  const QString name = arg.mid(9);
                  if (name.isEmpty())
                      return CommandLineArgumentsError;
                  if (++i == argumentCount)
                      return CommandLineArgumentsError;
                  const QString sizeStr = arguments.at(i);
                  const int idx = sizeStr.indexOf(QLatin1Char('x'));
                  if (idx == -1)
                      return CommandLineArgumentsError;
                  bool ok;
                  const int w = sizeStr.leftRef(idx).toInt(&ok);
                  if (!ok)
                      return CommandLineArgumentsError;
                  const int h = sizeStr.midRef(idx + 1).toInt(&ok);
                  if (!ok)
                      return CommandLineArgumentsError;
                  result->insert(name, QSize(w, h));
              } else if (arg == QLatin1String("-h") || arg == QLatin1String("--help")) {
                  return HelpRequested;
              } else {
                  return CommandLineArgumentsError;
              }
          }

          return CommandLineArgumentsOk;
      }

      int main(int argc, char **argv)
      {
          QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
          QApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
          QApplication app(argc, argv);
          MainWindow::CustomSizeHintMap customSizeHints;
          switch (parseCustomSizeHints(QCoreApplication::arguments(), &customSizeHints)) {
          case CommandLineArgumentsOk:
              break;
          case CommandLineArgumentsError:
              usage();
              return -1;
          case HelpRequested:
              usage();
              return 0;
          }
          MainWindow mainWin(customSizeHints);
          mainWin.resize(800, 600);
          mainWin.show();
          return app.exec();
      }