mainwindow.cpp Example File | Qt Widgets 5.12.9

- Qt 5.12
- Qt Widgets
- Character Map Example
- mainwindow.cpp Example File
- Qt 5.12.9 Reference Documentation

# mainwindow.cpp Example File

widgets/charactermap/mainwindow.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2016 The Qt Company Ltd.
     ** Contact: https://www.qt.io/licensing/
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** Commercial License Usage
     ** Licensees holding valid commercial Qt licenses may use this file in
     ** accordance with the commercial license agreement provided with the
     ** Software or, alternatively, in accordance with the terms contained in
     ** a written agreement between you and The Qt Company. For licensing terms
     ** and conditions see https://www.qt.io/terms-conditions. For further
     ** information use the contact form at https://www.qt.io/contact-us.
     **
     ** BSD License Usage
     ** Alternatively, you may use this file under the terms of the BSD license
     ** as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * Redistributions in binary form must reproduce the above copyright
     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
     **   * Neither the name of The Qt Company Ltd nor the names of its
     **     contributors may be used to endorse or promote products derived
     **     from this software without specific prior written permission.
     **
     **
     ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
     **
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #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();
     }