mainwindow.cpp Example File

widgets/charactermap/mainwindow.cpp 
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 #include <QtWidgets>

 #include "characterwidget.h"
 #include "mainwindow.h"


 Q_DECLARE_METATYPE(QFontComboBox::FontFilter)

 MainWindow::MainWindow()
 {
     QMenu *fileMenu = menuBar()->addMenu(tr("File"));
     fileMenu->addAction(tr("Quit"), this, &QWidget::close);
     QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
     helpMenu->addAction(tr("Show Font Info"), this, &MainWindow::showInfo);
     helpMenu->addAction(tr("About &Qt"), qApp, &QApplication::aboutQt);

     QWidget *centralWidget = new QWidget;

     QLabel *filterLabel = new QLabel(tr("Filter:"));
     filterCombo = new QComboBox;
     filterCombo->addItem(tr("All"), QVariant::fromValue(QFontComboBox::AllFonts));
     filterCombo->addItem(tr("Scalable"), QVariant::fromValue(QFontComboBox::ScalableFonts));
     filterCombo->addItem(tr("Monospaced"), QVariant::fromValue(QFontComboBox::MonospacedFonts));
     filterCombo->addItem(tr("Proportional"), QVariant::fromValue(QFontComboBox::ProportionalFonts));
     filterCombo->setCurrentIndex(0);
     connect(filterCombo, QOverload<int>::of(&QComboBox::currentIndexChanged),
             this, &MainWindow::filterChanged);

     QLabel *fontLabel = new QLabel(tr("Font:"));
     fontCombo = new QFontComboBox;
     QLabel *sizeLabel = new QLabel(tr("Size:"));
     sizeCombo = new QComboBox;
     QLabel *styleLabel = new QLabel(tr("Style:"));
     styleCombo = new QComboBox;
     QLabel *fontMergingLabel = new QLabel(tr("Automatic Font Merging:"));
     fontMerging = new QCheckBox;
     fontMerging->setChecked(true);

     scrollArea = new QScrollArea;
     characterWidget = new CharacterWidget;
     scrollArea->setWidget(characterWidget);

     findStyles(fontCombo->currentFont());
     findSizes(fontCombo->currentFont());

     lineEdit = new QLineEdit;
     lineEdit->setClearButtonEnabled(true);
 #ifndef QT_NO_CLIPBOARD
     QPushButton *clipboardButton = new QPushButton(tr("&To clipboard"));

 #endif

     connect(fontCombo, &QFontComboBox::currentFontChanged,
             this, &MainWindow::findStyles);
     connect(fontCombo, &QFontComboBox::currentFontChanged,
             this, &MainWindow::findSizes);
     connect(fontCombo, &QFontComboBox::currentFontChanged,
             characterWidget, &CharacterWidget::updateFont);
     connect(sizeCombo, QOverload<const QString &>::of(&QComboBox::currentIndexChanged),
             characterWidget, &CharacterWidget::updateSize);
     connect(styleCombo, QOverload<const QString &>::of(&QComboBox::currentIndexChanged),
             characterWidget, &CharacterWidget::updateStyle);
     connect(characterWidget, &CharacterWidget::characterSelected,
             this, &MainWindow::insertCharacter);

 #ifndef QT_NO_CLIPBOARD
     connect(clipboardButton, &QAbstractButton::clicked, this, &MainWindow::updateClipboard);
 #endif
     connect(fontMerging, &QAbstractButton::toggled, characterWidget, &CharacterWidget::updateFontMerging);

     QHBoxLayout *controlsLayout = new QHBoxLayout;
     controlsLayout->addWidget(filterLabel);
     controlsLayout->addWidget(filterCombo, 1);
     controlsLayout->addWidget(fontLabel);
     controlsLayout->addWidget(fontCombo, 1);
     controlsLayout->addWidget(sizeLabel);
     controlsLayout->addWidget(sizeCombo, 1);
     controlsLayout->addWidget(styleLabel);
     controlsLayout->addWidget(styleCombo, 1);
     controlsLayout->addWidget(fontMergingLabel);
     controlsLayout->addWidget(fontMerging, 1);
     controlsLayout->addStretch(1);

     QHBoxLayout *lineLayout = new QHBoxLayout;
     lineLayout->addWidget(lineEdit, 1);
     lineLayout->addSpacing(12);
 #ifndef QT_NO_CLIPBOARD
     lineLayout->addWidget(clipboardButton);
 #endif

     QVBoxLayout *centralLayout = new QVBoxLayout;
     centralLayout->addLayout(controlsLayout);
     centralLayout->addWidget(scrollArea, 1);
     centralLayout->addSpacing(4);
     centralLayout->addLayout(lineLayout);
     centralWidget->setLayout(centralLayout);

     setCentralWidget(centralWidget);
     setWindowTitle(tr("Character Map"));
 }

 void MainWindow::findStyles(const QFont &font)
 {
     QFontDatabase fontDatabase;
     QString currentItem = styleCombo->currentText();
     styleCombo->clear();

     QString style;
     foreach (style, fontDatabase.styles(font.family()))
         styleCombo->addItem(style);

     int styleIndex = styleCombo->findText(currentItem);

     if (styleIndex == -1)
         styleCombo->setCurrentIndex(0);
     else
         styleCombo->setCurrentIndex(styleIndex);
 }

 void MainWindow::filterChanged(int f)
 {
     const QFontComboBox::FontFilter filter =
         filterCombo->itemData(f).value<QFontComboBox::FontFilter>();
     fontCombo->setFontFilters(filter);
     statusBar()->showMessage(tr("%n font(s) found", 0, fontCombo->count()));
 }

 void MainWindow::findSizes(const QFont &font)
 {
     QFontDatabase fontDatabase;
     QString currentSize = sizeCombo->currentText();

     {
         const QSignalBlocker blocker(sizeCombo);
         // sizeCombo signals are now blocked until end of scope
         sizeCombo->clear();

         int size;
         if (fontDatabase.isSmoothlyScalable(font.family(), fontDatabase.styleString(font))) {
             foreach (size, QFontDatabase::standardSizes()) {
                 sizeCombo->addItem(QVariant(size).toString());
                 sizeCombo->setEditable(true);
             }

         } else {
             foreach (size, fontDatabase.smoothSizes(font.family(), fontDatabase.styleString(font))) {
                 sizeCombo->addItem(QVariant(size).toString());
                 sizeCombo->setEditable(false);
             }
         }
     }

     int sizeIndex = sizeCombo->findText(currentSize);

     if(sizeIndex == -1)
         sizeCombo->setCurrentIndex(qMax(0, sizeCombo->count() / 3));
     else
         sizeCombo->setCurrentIndex(sizeIndex);
 }

 void MainWindow::insertCharacter(const QString &character)
 {
     lineEdit->insert(character);
 }

 #ifndef QT_NO_CLIPBOARD
 void MainWindow::updateClipboard()
 {
     QGuiApplication::clipboard()->setText(lineEdit->text(), QClipboard::Clipboard);
     QGuiApplication::clipboard()->setText(lineEdit->text(), QClipboard::Selection);
 }
 #endif

 class FontInfoDialog : public QDialog
 {
 public:
     explicit FontInfoDialog(QWidget *parent = nullptr);

 private:
     QString text() const;
 };

 FontInfoDialog::FontInfoDialog(QWidget *parent) : QDialog(parent)
 {
     setWindowFlags(windowFlags() & ~Qt::WindowContextHelpButtonHint);
     QVBoxLayout *mainLayout = new QVBoxLayout(this);
     QPlainTextEdit *textEdit = new QPlainTextEdit(text(), this);
     textEdit->setReadOnly(true);
     textEdit->setFont(QFontDatabase::systemFont(QFontDatabase::FixedFont));
     mainLayout->addWidget(textEdit);
     QDialogButtonBox *buttonBox = new QDialogButtonBox(QDialogButtonBox::Close, this);
     connect(buttonBox, &QDialogButtonBox::rejected, this, &QDialog::reject);
     mainLayout->addWidget(buttonBox);
 }

 QString FontInfoDialog::text() const
 {
     QString text;
     QTextStream str(&text);
     const QFont defaultFont = QFontDatabase::systemFont(QFontDatabase::GeneralFont);
     const QFont fixedFont = QFontDatabase::systemFont(QFontDatabase::FixedFont);
     const QFont titleFont = QFontDatabase::systemFont(QFontDatabase::TitleFont);
     const QFont smallestReadableFont = QFontDatabase::systemFont(QFontDatabase::SmallestReadableFont);

     str << "Qt " << QT_VERSION_STR << " on " << QGuiApplication::platformName()
         << ", " << logicalDpiX() << "DPI";
     if (!qFuzzyCompare(devicePixelRatioF(), qreal(1)))
         str  << ", device pixel ratio: " << devicePixelRatioF();
     str << "\n\nDefault font : " << defaultFont.family() << ", " << defaultFont.pointSizeF() << "pt\n"
         << "Fixed font   : " << fixedFont.family() << ", " << fixedFont.pointSizeF() << "pt\n"
         << "Title font   : " << titleFont.family() << ", " << titleFont.pointSizeF() << "pt\n"
         << "Smallest font: " << smallestReadableFont.family() << ", " << smallestReadableFont.pointSizeF() << "pt\n";

     return text;
 }

 void MainWindow::showInfo()
 {
     const QRect screenGeometry = QApplication::desktop()->screenGeometry(this);
     FontInfoDialog *dialog = new FontInfoDialog(this);
     dialog->setWindowTitle(tr("Fonts"));
     dialog->setAttribute(Qt::WA_DeleteOnClose);
     dialog->resize(screenGeometry.width() / 4, screenGeometry.height() / 4);
     dialog->show();
 }

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