- Qt 5.5
- Qt Widgets
- Character Map Example
- mainwindow.cpp Example File
- Qt 5.5.1 Reference Documentation

# mainwindow.cpp Example File

widgets/charactermap/mainwindow.cpp

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
    ** 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
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    **   * Redistributions of source code must retain the above copyright
    **     notice, this list of conditions and the following disclaimer.
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    **     contributors may be used to endorse or promote products derived
    **     from this software without specific prior written permission.
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    #include <QtWidgets>

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

    MainWindow::MainWindow()
    {
        QWidget *centralWidget = new QWidget;

        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;
    #ifndef QT_NO_CLIPBOARD
        QPushButton *clipboardButton = new QPushButton(tr("&To clipboard"));

        clipboard = QApplication::clipboard();
    #endif

        connect(fontCombo, SIGNAL(currentFontChanged(QFont)),
                this, SLOT(findStyles(QFont)));
        connect(fontCombo, SIGNAL(currentFontChanged(QFont)),
                this, SLOT(findSizes(QFont)));
        connect(fontCombo, SIGNAL(currentFontChanged(QFont)),
                characterWidget, SLOT(updateFont(QFont)));
        connect(sizeCombo, SIGNAL(currentIndexChanged(QString)),
                characterWidget, SLOT(updateSize(QString)));
        connect(styleCombo, SIGNAL(currentIndexChanged(QString)),
                characterWidget, SLOT(updateStyle(QString)));
        connect(characterWidget, SIGNAL(characterSelected(QString)),
                this, SLOT(insertCharacter(QString)));

    #ifndef QT_NO_CLIPBOARD
        connect(clipboardButton, SIGNAL(clicked()), this, SLOT(updateClipboard()));
    #endif
        connect(fontMerging, SIGNAL(toggled(bool)), characterWidget, SLOT(updateFontMerging(bool)));

        QHBoxLayout *controlsLayout = new QHBoxLayout;
        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::findSizes(const QFont &font)
    {
        QFontDatabase fontDatabase;
        QString currentSize = sizeCombo->currentText();
        sizeCombo->blockSignals(true);
        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);
            }
        }

        sizeCombo->blockSignals(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()
    {
        clipboard->setText(lineEdit->text(), QClipboard::Clipboard);
        clipboard->setText(lineEdit->text(), QClipboard::Selection);
    }
    #endif