qfontcombobox.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qfontcombobox.h"
 
#include <qabstractitemdelegate.h>
#include <qaccessible.h>
#include <qstringlistmodel.h>
#include <qlistview.h>
#include <qpainter.h>
#include <qevent.h>
#include <qapplication.h>
#include <private/qcombobox_p.h>
#include <qdebug.h>
 
#include <array>
 
QT_BEGIN_NAMESPACE
 
using namespace Qt::StringLiterals;
 
static QFontDatabase::WritingSystem writingSystemFromScript(QLocale::Script script)
{
    switch (script) {
    case QLocale::ArabicScript:
        return QFontDatabase::Arabic;
    case QLocale::CyrillicScript:
        return QFontDatabase::Cyrillic;
    case QLocale::GurmukhiScript:
        return QFontDatabase::Gurmukhi;
    case QLocale::SimplifiedHanScript:
        return QFontDatabase::SimplifiedChinese;
    case QLocale::TraditionalHanScript:
        return QFontDatabase::TraditionalChinese;
    case QLocale::LatinScript:
        return QFontDatabase::Latin;
    case QLocale::ArmenianScript:
        return QFontDatabase::Armenian;
    case QLocale::BengaliScript:
        return QFontDatabase::Bengali;
    case QLocale::DevanagariScript:
        return QFontDatabase::Devanagari;
    case QLocale::GeorgianScript:
        return QFontDatabase::Georgian;
    case QLocale::GreekScript:
        return QFontDatabase::Greek;
    case QLocale::GujaratiScript:
        return QFontDatabase::Gujarati;
    case QLocale::HebrewScript:
        return QFontDatabase::Hebrew;
    case QLocale::JapaneseScript:
        return QFontDatabase::Japanese;
    case QLocale::KhmerScript:
        return QFontDatabase::Khmer;
    case QLocale::KannadaScript:
        return QFontDatabase::Kannada;
    case QLocale::KoreanScript:
        return QFontDatabase::Korean;
    case QLocale::LaoScript:
        return QFontDatabase::Lao;
    case QLocale::MalayalamScript:
        return QFontDatabase::Malayalam;
    case QLocale::MyanmarScript:
        return QFontDatabase::Myanmar;
    case QLocale::TamilScript:
        return QFontDatabase::Tamil;
    case QLocale::TeluguScript:
        return QFontDatabase::Telugu;
    case QLocale::ThaanaScript:
        return QFontDatabase::Thaana;
    case QLocale::ThaiScript:
        return QFontDatabase::Thai;
    case QLocale::TibetanScript:
        return QFontDatabase::Tibetan;
    case QLocale::SinhalaScript:
        return QFontDatabase::Sinhala;
    case QLocale::SyriacScript:
        return QFontDatabase::Syriac;
    case QLocale::OriyaScript:
        return QFontDatabase::Oriya;
    case QLocale::OghamScript:
        return QFontDatabase::Ogham;
    case QLocale::RunicScript:
        return QFontDatabase::Runic;
    case QLocale::NkoScript:
        return QFontDatabase::Nko;
    default:
        return QFontDatabase::Any;
    }
}
 
static QFontDatabase::WritingSystem writingSystemFromLocale()
{
    QStringList uiLanguages = QLocale::system().uiLanguages();
    QLocale::Script script;
    if (!uiLanguages.isEmpty())
        script = QLocale(uiLanguages.at(0)).script();
    else
        script = QLocale::system().script();
 
    return writingSystemFromScript(script);
}
 
static QFontDatabase::WritingSystem writingSystemForFont(const QFont &font, bool *hasLatin)
{
    QList<QFontDatabase::WritingSystem> writingSystems = QFontDatabase::writingSystems(font.families().constFirst());
//     qDebug() << font.families().first() << writingSystems;
 
    // this just confuses the algorithm below. Vietnamese is Latin with lots of special chars
    writingSystems.removeOne(QFontDatabase::Vietnamese);
    *hasLatin = writingSystems.removeOne(QFontDatabase::Latin);
 
    if (writingSystems.isEmpty())
        return QFontDatabase::Any;
 
    QFontDatabase::WritingSystem system = writingSystemFromLocale();
 
    if (writingSystems.contains(system))
        return system;
 
    if (system == QFontDatabase::TraditionalChinese
            && writingSystems.contains(QFontDatabase::SimplifiedChinese)) {
        return QFontDatabase::SimplifiedChinese;
    }
 
    if (system == QFontDatabase::SimplifiedChinese
            && writingSystems.contains(QFontDatabase::TraditionalChinese)) {
        return QFontDatabase::TraditionalChinese;
    }
 
    system = writingSystems.constLast();
 
    if (!*hasLatin) {
        // we need to show something
        return system;
    }
 
    if (writingSystems.size() == 1 && system > QFontDatabase::Cyrillic)
        return system;
 
    if (writingSystems.size() <= 2 && system > QFontDatabase::Armenian && system < QFontDatabase::Vietnamese)
        return system;
 
    if (writingSystems.size() <= 5 && system >= QFontDatabase::SimplifiedChinese && system <= QFontDatabase::Korean)
        return system;
 
    return QFontDatabase::Any;
}
 
class QFontComboBoxPrivate : public QComboBoxPrivate
{
public:
    QFontComboBox::FontFilters filters = QFontComboBox::AllFonts;
    QFont currentFont;
    QHash<QFontDatabase::WritingSystem, QString> sampleTextForWritingSystem;
    QHash<QString, QString> sampleTextForFontFamily;
    QHash<QString, QFont> displayFontForFontFamily;
    std::array<QMetaObject::Connection, 2> connections;
 
    void updateModel();
    void currentChanged(const QString &);
 
    Q_DECLARE_PUBLIC(QFontComboBox)
};
 
class QFontFamilyDelegate : public QAbstractItemDelegate
{
    Q_OBJECT
public:
    explicit QFontFamilyDelegate(QObject *parent, QFontComboBoxPrivate *comboP);
 
    // painting
    void paint(QPainter *painter,
               const QStyleOptionViewItem &option,
               const QModelIndex &index) const override;
 
    QSize sizeHint(const QStyleOptionViewItem &option,
                   const QModelIndex &index) const override;
 
    const QIcon truetype;
    const QIcon bitmap;
    QFontDatabase::WritingSystem writingSystem;
    QFontComboBoxPrivate *comboPrivate;
};
 
QFontFamilyDelegate::QFontFamilyDelegate(QObject *parent, QFontComboBoxPrivate *comboP)
    : QAbstractItemDelegate(parent),
      truetype(QStringLiteral(":/qt-project.org/styles/commonstyle/images/fonttruetype-16.png")),
      bitmap(QStringLiteral(":/qt-project.org/styles/commonstyle/images/fontbitmap-16.png")),
      writingSystem(QFontDatabase::Any),
      comboPrivate(comboP)
{
}
 
void QFontFamilyDelegate::paint(QPainter *painter,
                                const QStyleOptionViewItem &option,
                                const QModelIndex &index) const
{
    QString text = index.data(Qt::DisplayRole).toString();
    QFont font(option.font);
    font.setPointSize(QFontInfo(font).pointSize() * 3 / 2);
    QFont font2 = font;
    font2.setFamilies(QStringList{text});
 
    bool hasLatin;
    QFontDatabase::WritingSystem system = writingSystemForFont(font2, &hasLatin);
    if (hasLatin)
        font = font2;
 
    font = comboPrivate->displayFontForFontFamily.value(text, font);
 
    QRect r = option.rect;
 
    if (option.state & QStyle::State_Selected) {
        painter->save();
        painter->setBrush(option.palette.highlight());
        painter->setPen(Qt::NoPen);
        painter->drawRect(option.rect);
        painter->setPen(QPen(option.palette.highlightedText(), 0));
    }
 
    const QIcon *icon = &bitmap;
    if (QFontDatabase::isSmoothlyScalable(text)) {
        icon = &truetype;
    }
    const QSize actualSize = icon->actualSize(r.size());
    const QRect iconRect = QStyle::alignedRect(option.direction, option.displayAlignment,
                                               actualSize, r);
    icon->paint(painter, iconRect, Qt::AlignLeft|Qt::AlignVCenter);
    if (option.direction == Qt::RightToLeft)
        r.setRight(r.right() - actualSize.width() - 4);
    else
        r.setLeft(r.left() + actualSize.width() + 4);
 
    QFont old = painter->font();
    painter->setFont(font);
 
    const Qt::Alignment textAlign = QStyle::visualAlignment(option.direction, option.displayAlignment);
    // If the ascent of the font is larger than the height of the rect,
    // we will clip the text, so it's better to align the tight bounding rect in this case
    // This is specifically for fonts where the ascent is very large compared to
    // the descent, like certain of the Stix family.
    QFontMetricsF fontMetrics(font);
    if (fontMetrics.ascent() > r.height()) {
        QRectF tbr = fontMetrics.tightBoundingRect(text);
        QRect textRect(r);
        textRect.setHeight(textRect.height() + (r.height() - tbr.height()));
        painter->drawText(textRect, Qt::AlignBottom|Qt::TextSingleLine|textAlign, text);
    } else {
        painter->drawText(r, Qt::AlignVCenter|Qt::TextSingleLine|textAlign, text);
    }
 
    if (writingSystem != QFontDatabase::Any)
        system = writingSystem;
 
    const QString sampleText = comboPrivate->sampleTextForFontFamily.value(text, comboPrivate->sampleTextForWritingSystem.value(system));
    if (system != QFontDatabase::Any || !sampleText.isEmpty()) {
        int w = painter->fontMetrics().horizontalAdvance(text + "  "_L1);
        painter->setFont(font2);
        const QString sample = !sampleText.isEmpty() ? sampleText : QFontDatabase::writingSystemSample(system);
        if (option.direction == Qt::RightToLeft)
            r.setRight(r.right() - w);
        else
            r.setLeft(r.left() + w);
        painter->drawText(r, Qt::AlignVCenter|Qt::TextSingleLine|textAlign, sample);
    }
    painter->setFont(old);
 
    if (option.state & QStyle::State_Selected)
        painter->restore();
 
}
 
QSize QFontFamilyDelegate::sizeHint(const QStyleOptionViewItem &option,
                                    const QModelIndex &index) const
{
    QString text = index.data(Qt::DisplayRole).toString();
    QFont font(option.font);
//     font.setFamilies(QStringList{text});
    font.setPointSize(QFontInfo(font).pointSize() * 3/2);
    QFontMetrics fontMetrics(font);
    return QSize(fontMetrics.horizontalAdvance(text), fontMetrics.height());
}
 
 
void QFontComboBoxPrivate::updateModel()
{
    Q_Q(QFontComboBox);
 
    if (QCoreApplication::closingDown())
        return;
 
    const int scalableMask = (QFontComboBox::ScalableFonts | QFontComboBox::NonScalableFonts);
    const int spacingMask = (QFontComboBox::ProportionalFonts | QFontComboBox::MonospacedFonts);
 
    QStringListModel *m = qobject_cast<QStringListModel *>(q->model());
    if (!m)
        return;
    QFontFamilyDelegate *delegate = qobject_cast<QFontFamilyDelegate *>(q->view()->itemDelegate());
    QFontDatabase::WritingSystem system = delegate ? delegate->writingSystem : QFontDatabase::Any;
 
    const QStringList list = QFontDatabase::families(system);
    QStringList result;
 
    int offset = 0;
    QFontInfo fi(currentFont);
 
    for (const auto &family : list) {
        if (QFontDatabase::isPrivateFamily(family))
            continue;
 
        if ((filters & scalableMask) && (filters & scalableMask) != scalableMask) {
            if (bool(filters & QFontComboBox::ScalableFonts) != QFontDatabase::isSmoothlyScalable(family))
                continue;
        }
        if ((filters & spacingMask) && (filters & spacingMask) != spacingMask) {
            if (bool(filters & QFontComboBox::MonospacedFonts) != QFontDatabase::isFixedPitch(family))
                continue;
        }
        result += family;
        if (family == fi.family() || family.startsWith(fi.family() + " ["_L1))
            offset = result.size() - 1;
    }
 
    //we need to block the signals so that the model doesn't emit reset
    //this prevents the current index from changing
    //it will be updated just after this
    {
        const QSignalBlocker blocker(m);
        m->setStringList(result);
        // Since the modelReset signal is blocked the view will not emit an accessibility event
    #if QT_CONFIG(accessibility)
        if (QAccessible::isActive()) {
            QAccessibleTableModelChangeEvent accessibleEvent(q->view(), QAccessibleTableModelChangeEvent::ModelReset);
            QAccessible::updateAccessibility(&accessibleEvent);
        }
    #endif
    }
 
    if (result.isEmpty()) {
        if (currentFont != QFont()) {
            currentFont = QFont();
            emit q->currentFontChanged(currentFont);
        }
    } else {
        q->setCurrentIndex(offset);
    }
}
 
 
void QFontComboBoxPrivate::currentChanged(const QString &text)
{
    Q_Q(QFontComboBox);
    const QStringList families = currentFont.families();
    if (families.isEmpty() || families.first() != text) {
        currentFont.setFamilies(QStringList{text});
        emit q->currentFontChanged(currentFont);
    }
}
 
QFontComboBox::QFontComboBox(QWidget *parent)
    : QComboBox(*new QFontComboBoxPrivate, parent)
{
    Q_D(QFontComboBox);
    d->currentFont = font();
    setEditable(true);
 
    QStringListModel *m = new QStringListModel(this);
    setModel(m);
    setItemDelegate(new QFontFamilyDelegate(this, d));
    QListView *lview = qobject_cast<QListView*>(view());
    if (lview)
        lview->setUniformItemSizes(true);
    setWritingSystem(QFontDatabase::Any);
 
    d->connections = {
        QObjectPrivate::connect(this, &QFontComboBox::currentTextChanged,
                                d, &QFontComboBoxPrivate::currentChanged),
        QObjectPrivate::connect(qApp, &QGuiApplication::fontDatabaseChanged,
                                d, &QFontComboBoxPrivate::updateModel),
    };
}
 
 
QFontComboBox::~QFontComboBox()
{
    Q_D(const QFontComboBox);
    for (const QMetaObject::Connection &connection : d->connections)
        QObject::disconnect(connection);
}
 
void QFontComboBox::setWritingSystem(QFontDatabase::WritingSystem script)
{
    Q_D(QFontComboBox);
    QFontFamilyDelegate *delegate = qobject_cast<QFontFamilyDelegate *>(view()->itemDelegate());
    if (delegate)
        delegate->writingSystem = script;
    d->updateModel();
}
 
QFontDatabase::WritingSystem QFontComboBox::writingSystem() const
{
    QFontFamilyDelegate *delegate = qobject_cast<QFontFamilyDelegate *>(view()->itemDelegate());
    if (delegate)
        return delegate->writingSystem;
    return QFontDatabase::Any;
}
 
 
void QFontComboBox::setFontFilters(FontFilters filters)
{
    Q_D(QFontComboBox);
    d->filters = filters;
    d->updateModel();
}
 
QFontComboBox::FontFilters QFontComboBox::fontFilters() const
{
    Q_D(const QFontComboBox);
    return d->filters;
}
 
QFont QFontComboBox::currentFont() const
{
    Q_D(const QFontComboBox);
    return d->currentFont;
}
 
void QFontComboBox::setCurrentFont(const QFont &font)
{
    Q_D(QFontComboBox);
    if (font != d->currentFont) {
        d->currentFont = font;
        d->updateModel();
        if (d->currentFont == font) { //else the signal has already be emitted by updateModel
            emit currentFontChanged(d->currentFont);
        }
    }
}
 
bool QFontComboBox::event(QEvent *e)
{
    if (e->type() == QEvent::Resize) {
        QListView *lview = qobject_cast<QListView*>(view());
        if (lview) {
            lview->window()->setFixedWidth(qMin(width() * 5 / 3,
                                           QWidgetPrivate::availableScreenGeometry(lview).width()));
        }
    }
    return QComboBox::event(e);
}
 
QSize QFontComboBox::sizeHint() const
{
    QSize sz = QComboBox::sizeHint();
    QFontMetrics fm(font());
    sz.setWidth(fm.horizontalAdvance(u'm') * 14);
    return sz;
}
 
void QFontComboBox::setSampleTextForSystem(QFontDatabase::WritingSystem writingSystem, const QString &sampleText)
{
    Q_D(QFontComboBox);
    d->sampleTextForWritingSystem[writingSystem] = sampleText;
}
 
 
QString QFontComboBox::sampleTextForSystem(QFontDatabase::WritingSystem writingSystem) const
{
    Q_D(const QFontComboBox);
    return d->sampleTextForWritingSystem.value(writingSystem);
}
 
void QFontComboBox::setSampleTextForFont(const QString &fontFamily, const QString &sampleText)
{
    Q_D(QFontComboBox);
    d->sampleTextForFontFamily[fontFamily] = sampleText;
}
 
QString QFontComboBox::sampleTextForFont(const QString &fontFamily) const
{
    Q_D(const QFontComboBox);
    return d->sampleTextForFontFamily.value(fontFamily);
}
 
void QFontComboBox::setDisplayFont(const QString &fontFamily, const QFont &font)
{
    Q_D(QFontComboBox);
    d->displayFontForFontFamily[fontFamily] = font;
}
 
std::optional<QFont> QFontComboBox::displayFont(const QString &fontFamily) const
{
    Q_D(const QFontComboBox);
    return d->displayFontForFontFamily.value(fontFamily, {});
}
 
QT_END_NAMESPACE
 
#include "qfontcombobox.moc"
#include "moc_qfontcombobox.cpp"