qskinny/src/controls/QskVirtualKeyboard.cpp

/******************************************************************************
 * QSkinny - Copyright (C) 2016 Uwe Rathmann
 * This file may be used under the terms of the QSkinny License, Version 1.0
 *****************************************************************************/

#include "QskVirtualKeyboard.h"
#include "QskTextOptions.h"
#include "QskLinearBox.h"

#include <QGuiApplication>
#include <QStyleHints>

QSK_QT_PRIVATE_BEGIN
#include <private/qguiapplication_p.h>
QSK_QT_PRIVATE_END

#include <qpa/qplatformintegration.h>
#include <qpa/qplatforminputcontext.h>

namespace
{
    struct KeyTable
    {
        using Row = QskVirtualKeyboard::KeyData[ QskVirtualKeyboard::KeyCount ];
        Row data[ QskVirtualKeyboard::RowCount ];

        int indexOf( const QskVirtualKeyboard::KeyData* value ) const
        {
            return int( intptr_t( value - data[0] ) );
        }
    };
}

struct QskVirtualKeyboardLayouts
{
    struct KeyCodes
    {
        using Row = Qt::Key[ QskVirtualKeyboard::KeyCount ];
        Row data[ QskVirtualKeyboard::RowCount ];
    };

    using Layout = KeyCodes[ QskVirtualKeyboard::ModeCount ];

    Layout bg; // Bulgarian
    Layout cs; // Czech
    Layout de; // German
    Layout da; // Danish
    Layout el; // Greek
    Layout en_GB; // English (GB)
    Layout en_US; // English (US)
    Layout es; // Spanish
    Layout fi; // Finnish
    Layout fr; // French
    Layout hu; // Hungarian
    Layout it; // Italian
    Layout ja; // Japanese
    Layout lv; // Latvian
    Layout lt; // Lithuanian
    Layout nl; // Dutch
    Layout pt; // Portuguese
    Layout ro; // Romanian
    Layout ru; // Russian
    Layout sl; // Slovene
    Layout sk; // Slovak
    Layout tr; // Turkish
    Layout zh; // Chinese

    Q_GADGET
};

#define LOWER(x) Qt::Key(x + 32) // Convert an uppercase key to lowercase
static constexpr const QskVirtualKeyboardLayouts qskKeyboardLayouts =
{
#include "QskVirtualKeyboardLayouts.cpp"
};
#undef LOWER

QSK_DECLARE_OPERATORS_FOR_FLAGS( Qt::Key ) // Must appear after the LOWER macro

static const int KeyLocked =  static_cast< int >( Qt::ControlModifier );
static const int KeyStates =  static_cast< int >( Qt::KeyboardModifierMask );

static qreal qskKeyStretch( Qt::Key key )
{
    switch( key )
    {
        case Qt::Key_Backspace:
        case Qt::Key_Shift:
        case Qt::Key_CapsLock:
            return 1.5;

        case Qt::Key_Space:
            return 3.5;

        case Qt::Key_Return:
        case Qt::Key_Mode_switch:

        // Possibly smaller
        default:
            break;
    }

    return 1.0;
}

static qreal qskRowStretch( const QskVirtualKeyboard::KeyRow& keyRow )
{
    qreal stretch = 0;

    for( const auto& key : keyRow )
    {
        if( !key )
        {
            continue;
        }

        stretch += qskKeyStretch( key );
    }

    if( stretch == 0.0 )
    {
        stretch = QskVirtualKeyboard::KeyCount;
    }

    return stretch;
}

static bool qskIsAutorepeat( int key )
{
    return ( key != Qt::Key_Return && key != Qt::Key_Enter
        && key != Qt::Key_Shift && key != Qt::Key_CapsLock
        && key != Qt::Key_Mode_switch );
}

static inline QPlatformInputContext* qskInputContext()
{
    return QGuiApplicationPrivate::platformIntegration()->inputContext();
}

QSK_SUBCONTROL( QskVirtualKeyboardCandidateButton, Panel )
QSK_SUBCONTROL( QskVirtualKeyboardCandidateButton, Text )

QskVirtualKeyboardCandidateButton::QskVirtualKeyboardCandidateButton(
        QskVirtualKeyboard* inputPanel, QQuickItem* parent ) :
    Inherited( parent ),
    m_inputPanel( inputPanel ),
    m_index( -1 )
{
    setFlag( QQuickItem::ItemAcceptsInputMethod );
    setText( QStringLiteral( " " ) ); // ###

    connect( this, &QskVirtualKeyboardButton::pressed,
        this, [ this ]() { m_inputPanel->handleCandidateKey( m_index, m_text ); } );
}

void QskVirtualKeyboardCandidateButton::setIndexAndText(int index, const QString& text )
{
    m_index = index;
    m_text = text;
    setText( m_text );
}

QskAspect::Subcontrol QskVirtualKeyboardCandidateButton::effectiveSubcontrol(
    QskAspect::Subcontrol subControl ) const
{
    if( subControl == QskPushButton::Panel )
    {
        return QskVirtualKeyboardCandidateButton::Panel;
    }

    if( subControl == QskPushButton::Text )
    {
        return QskVirtualKeyboardCandidateButton::Text;
    }

    return subControl;
}

int QskVirtualKeyboardCandidateButton::maxCandidates()
{
    return 12;
}

QSK_SUBCONTROL( QskVirtualKeyboard, Panel )

QSK_SUBCONTROL( QskVirtualKeyboardButton, Panel )
QSK_SUBCONTROL( QskVirtualKeyboardButton, Text )

QskVirtualKeyboardButton::QskVirtualKeyboardButton(
        int keyIndex, QskVirtualKeyboard* inputPanel, QQuickItem* parent ) :
    Inherited( parent ),
    m_keyIndex( keyIndex ),
    m_inputPanel( inputPanel )
{
    QskTextOptions options;
    options.setFontSizeMode( QskTextOptions::VerticalFit );
    setTextOptions( options );

    setFocusPolicy( Qt::TabFocus );

    auto keyData = m_inputPanel->keyDataAt( m_keyIndex );
    const auto key = keyData.key & ~KeyStates;

    if ( qskIsAutorepeat( key ) )
    {
        setAutoRepeat( true );
        setAutoRepeatDelay( 500 );
        setAutoRepeatInterval( 1000 / QGuiApplication::styleHints()->keyboardAutoRepeatRate() );
    }

    updateText();

    connect( this, &QskVirtualKeyboardButton::pressed, this,
        [ this ]() { m_inputPanel->handleKey( m_keyIndex ); } );

    connect( m_inputPanel, &QskVirtualKeyboard::modeChanged,
        this, &QskVirtualKeyboardButton::updateText );
}

QskAspect::Subcontrol QskVirtualKeyboardButton::effectiveSubcontrol(
    QskAspect::Subcontrol subControl ) const
{
    if( subControl == QskPushButton::Panel )
        return QskVirtualKeyboardButton::Panel;

    if( subControl == QskPushButton::Text )
        return QskVirtualKeyboardButton::Text;

    return subControl;
}

int QskVirtualKeyboardButton::keyIndex() const
{
    return m_keyIndex;
}

void QskVirtualKeyboardButton::updateText()
{
    QString text = m_inputPanel->currentTextForKeyIndex( m_keyIndex );

    if( text.count() == 1 && text.at( 0 ) == QChar( 0 ) )
    {
        setVisible( false );
    }
    else
    {
        setVisible( true );
        setText( text );
    }
}

class QskVirtualKeyboard::PrivateData
{
public:
    PrivateData():
        currentLayout( nullptr ),
        mode( QskVirtualKeyboard::LowercaseMode ),
        selectedGroup( -1 ),
        candidateOffset( 0 ),
        candidateBox( nullptr ),
        buttonsBox( nullptr ),
        isUIInitialized( false ),
        candidateBoxVisible( false )
    {
    }

public:
    const QskVirtualKeyboardLayouts::Layout* currentLayout;
    QskVirtualKeyboard::Mode mode;

    qint16 selectedGroup;
    qint32 candidateOffset;

    QVector< QString > candidates;

    KeyTable keyTable[ ModeCount ];

    QList< QskVirtualKeyboardCandidateButton* > candidateButtons;
    QskLinearBox* candidateBox;
    QskLinearBox* buttonsBox;
    QList< QskVirtualKeyboardButton* > keyButtons;
    bool isUIInitialized;
    bool candidateBoxVisible;
};

QskVirtualKeyboard::QskVirtualKeyboard( QQuickItem* parent ):
    Inherited( parent ),
    m_data( new PrivateData )
{
    qRegisterMetaType< Qt::Key >();

    setFlag( ItemHasContents );
    setAcceptedMouseButtons( Qt::LeftButton );

    initSizePolicy( QskSizePolicy::Expanding, QskSizePolicy::Expanding );

    updateLocale( locale() );

    connect( this, &QskControl::localeChanged,
        this, &QskVirtualKeyboard::updateLocale );

    setFlag( ItemIsFocusScope, true );

#if 0
    setTabFence( true );
#endif

    setAutoLayoutChildren( true );

    m_data->buttonsBox = new QskLinearBox( Qt::Vertical, this );
    m_data->buttonsBox->setAutoAddChildren( true );

    const auto& panelKeyData = keyData();

    for( const auto& keyRow : panelKeyData )
    {
        auto rowBox = new QskLinearBox( Qt::Horizontal, m_data->buttonsBox );
        rowBox->setAutoAddChildren( true );

        for( const auto& keyData : keyRow )
        {
            if( !keyData.key )
                continue;

            const int keyIndex = m_data->keyTable[ m_data->mode ].indexOf( &keyData );

            auto button = new QskVirtualKeyboardButton( keyIndex, this, rowBox );
            button->installEventFilter( this );
            rowBox->setRetainSizeWhenHidden( button, true );

            m_data->keyButtons.append( button );
        }
    }

    connect( this, &QskVirtualKeyboard::modeChanged,
        this, [ this ]() { updateLayout(); } );
}

QskVirtualKeyboard::~QskVirtualKeyboard()
{
}

QskAspect::Subcontrol QskVirtualKeyboard::effectiveSubcontrol(
    QskAspect::Subcontrol subControl ) const
{
    if( subControl == QskBox::Panel )
        return QskVirtualKeyboard::Panel;

    return subControl;
}


QskVirtualKeyboard::Mode QskVirtualKeyboard::mode() const
{
    return m_data->mode;
}

const QskVirtualKeyboard::KeyDataSet& QskVirtualKeyboard::keyData( Mode mode ) const
{
    mode = mode == CurrentMode ? m_data->mode : mode;
    Q_ASSERT( mode >= 0 && mode < ModeCount );
    return m_data->keyTable[ mode ].data;
}

QString QskVirtualKeyboard::textForKey( int key ) const
{
    key &= ~KeyStates;

    // Special cases
    switch( key )
    {
        case Qt::Key_Backspace:
        case Qt::Key_Muhenkan:
            return QChar( 0x232B );

        case Qt::Key_CapsLock:
        case Qt::Key_Kana_Lock:
            return QChar( 0x21E7 );

        case Qt::Key_Shift:
        case Qt::Key_Kana_Shift:
            return QChar( 0x2B06 );

        case Qt::Key_Mode_switch:
            return QChar( 0x2026 );

        case Qt::Key_Return:
        case Qt::Key_Kanji:
            return QChar( 0x23CE );

        case Qt::Key_Left:
            return QChar( 0x2190 );

        case Qt::Key_Right:
            return QChar( 0x2192 );

        case Qt::Key_ApplicationLeft:
            return QChar( 0x2B05 );

        case Qt::Key_ApplicationRight:
            return QChar( 0x27A1 );

        default:
            break;
    }

    // TODO: possibly route through locale for custom strings

    // Default to direct key mapping
    return QChar( key );
}

QString QskVirtualKeyboard::displayLanguageName() const
{
    const auto locale = this->locale();

    switch( locale.language() )
    {
        case QLocale::Bulgarian:
            return QStringLiteral( "български език" );

        case QLocale::Czech:
            return QStringLiteral( "Čeština" );

        case QLocale::German:
            return QStringLiteral( "Deutsch" );

        case QLocale::Danish:
            return QStringLiteral( "Dansk" );

        case QLocale::Greek:
            return QStringLiteral( "Eλληνικά" );

        case QLocale::English:
        {
            switch( locale.country() )
            {
                case QLocale::Canada:
                case QLocale::UnitedStates:
                case QLocale::UnitedStatesMinorOutlyingIslands:
                case QLocale::UnitedStatesVirginIslands:
                    return QStringLiteral( "English (US)" );

                default:
                    return QStringLiteral( "English (UK)" );
            }

            break;
        }

        case QLocale::Spanish:
            return QStringLiteral( "Español" );

        case QLocale::Finnish:
            return QStringLiteral( "Suomi" );

        case QLocale::French:
            return QStringLiteral( "Français" );

        case QLocale::Hungarian:
            return QStringLiteral( "Magyar" );

        case QLocale::Italian:
            return QStringLiteral( "Italiano" );

        case QLocale::Japanese:
            return QStringLiteral( "日本語" );

        case QLocale::Latvian:
            return QStringLiteral( "Latviešu" );

        case QLocale::Lithuanian:
            return QStringLiteral( "Lietuvių" );

        case QLocale::Dutch:
            return QStringLiteral( "Nederlands" );

        case QLocale::Portuguese:
            return QStringLiteral( "Português" );

        case QLocale::Romanian:
            return QStringLiteral( "Română" );

        case QLocale::Russia:
            return QStringLiteral( "Русский" );

        case QLocale::Slovenian:
            return QStringLiteral( "Slovenščina" );

        case QLocale::Slovak:
            return QStringLiteral( "Slovenčina" );

        case QLocale::Turkish:
            return QStringLiteral( "Türkçe" );

        case QLocale::Chinese:
            return QStringLiteral( "中文" );

        default:
            break;
    }

    return QLocale::languageToString( locale.language() );
}

void QskVirtualKeyboard::setPreeditCandidates( const QVector< QString >& candidates )
{
    if( m_data->candidates == candidates )
    {
        return;
    }

    m_data->candidates = candidates;
    setCandidateOffset( 0 );
}

void QskVirtualKeyboard::setCandidateOffset( int candidateOffset )
{
    m_data->candidateOffset = candidateOffset;

    const auto candidateCount = m_data->candidates.length();
    const auto count = std::min( candidateCount, QskVirtualKeyboardCandidateButton::maxCandidates() );
    const bool continueLeft = m_data->candidateOffset > 0;
    const bool continueRight = ( candidateCount - m_data->candidateOffset ) > count;

    for( int i = 0; i < count; ++i )
    {
        auto button = m_data->candidateButtons[i];

        if( continueLeft && i == 0 )
        {
            button->setIndexAndText( i, textForKey( Qt::Key_ApplicationLeft ) );
        }
        else if( continueRight && ( i == KeyCount - 1 ) )
        {
            button->setIndexAndText( i, textForKey( Qt::Key_ApplicationRight ) );
        }
        else
        {
            const int index = i + m_data->candidateOffset;
            button->setIndexAndText( index, m_data->candidates[index] );
        }
    }

    for( int i = count; i < QskVirtualKeyboardCandidateButton::maxCandidates(); ++i )
    {
        m_data->candidateButtons[i]->setIndexAndText( -1, QString() );
    }
}

void QskVirtualKeyboard::geometryChanged(
    const QRectF& newGeometry, const QRectF& oldGeometry )
{
    Inherited::geometryChanged( newGeometry, oldGeometry );
    Q_EMIT keyboardRectChanged();
}

void QskVirtualKeyboard::updateLayout()
{
    if( geometry().isNull() )
        return; // no need to calculate anything, will be called again

    QRectF rect = layoutRect();
    qreal verticalSpacing = m_data->buttonsBox->spacing();

    const auto& children = m_data->buttonsBox->childItems();
    for( auto rowItem : children )
    {
        auto rowBox = qobject_cast< QskLinearBox* >( rowItem );
        const qreal horizontalSpacing = rowBox->spacing();

        const auto& rowChildren = rowBox->childItems();
        for( auto keyItem : rowChildren )
        {
            auto button = qobject_cast< QskVirtualKeyboardButton* >( keyItem );
            QRectF keyRect = keyDataAt( button->keyIndex() ).rect;
            qreal width = keyRect.width() * rect.width() - horizontalSpacing;
            qreal height = keyRect.height() * rect.height() - verticalSpacing;

            button->setFixedSize( width, height );
        }
    }
}

void QskVirtualKeyboard::createUI()
{
    setAutoLayoutChildren( true );

    auto outerBox = new QskLinearBox( Qt::Vertical, this );

    m_data->candidateBox = new QskLinearBox( Qt::Horizontal, outerBox );
#if 1
    // should be skin hints TODO ...
    QMarginsF margins( 0, 10, 0, 20 ); // ###
    m_data->candidateBox->setMargins( margins );
#endif

    // to determine suggestions buttons width
    // (otherwise empty buttons would be too small when there are only a few suggestions):
    // ### Can this be done with the layout engine or so?
    QRectF rect = layoutRect();
    auto candidateButtonWidth = rect.width() / QskVirtualKeyboardCandidateButton::maxCandidates()
        - m_data->candidateBox->spacing() * QskVirtualKeyboardCandidateButton::maxCandidates();

    for( int a = 0; a < QskVirtualKeyboardCandidateButton::maxCandidates(); ++a )
    {
        auto button = new QskVirtualKeyboardCandidateButton( this, m_data->candidateBox );

        qreal height = button->sizeHint().height();
#if 1
        // should be done by margins/paddings
        button->setPreferredHeight( height + 10 );
#endif
        button->setPreferredWidth( candidateButtonWidth );
        button->installEventFilter( this );

        m_data->candidateBox->setRetainSizeWhenHidden( button, true );
        m_data->candidateButtons.append( button );
    }

    m_data->candidateBox->setVisible( m_data->candidateBoxVisible );
    outerBox->setRetainSizeWhenHidden( m_data->candidateBox, true );
}

void QskVirtualKeyboard::updateUI()
{
    for( auto button : qskAsConst( m_data->keyButtons ) )
        button->updateText();
}

QskVirtualKeyboard::KeyData& QskVirtualKeyboard::keyDataAt( int keyIndex ) const
{
    const auto row = keyIndex / KeyCount;
    const auto col = keyIndex % KeyCount;

    return m_data->keyTable[ m_data->mode ].data[ row ][ col ];
}

void QskVirtualKeyboard::handleKey( int keyIndex )
{
    KeyData keyData = keyDataAt( keyIndex );
    const auto key = keyData.key & ~KeyStates;

    // Mode-switching keys
    switch( key )
    {
        case Qt::Key_CapsLock:
        case Qt::Key_Kana_Lock:
            setMode( UppercaseMode ); // Lock caps
            return;

        case Qt::Key_Shift:
        case Qt::Key_Kana_Shift:
            setMode( LowercaseMode ); // Unlock caps
            return;

        case Qt::Key_Mode_switch: // Cycle through modes, but skip caps
            setMode( static_cast< QskVirtualKeyboard::Mode >(
                m_data->mode ? ( ( m_data->mode + 1 ) % QskVirtualKeyboard::ModeCount )
                : SpecialCharacterMode ) );
            return;

        default:
            break;
    }

    compose( key );
}

void QskVirtualKeyboard::handleCandidateKey( int index, const QString& text )
{
    if( text == textForKey( Qt::Key_ApplicationLeft ) )
    {
        setCandidateOffset( m_data->candidateOffset - 1 );
    }
    else if( text == textForKey( Qt::Key_ApplicationRight ) )
    {
        setCandidateOffset( m_data->candidateOffset + 1 );
    }
    else
    {
        selectCandidate( index );
    }
}

void QskVirtualKeyboard::setCandidateBarVisible( bool visible )
{
    // need to cache it until we have created the UI
    m_data->candidateBoxVisible = visible;
    if( m_data->isUIInitialized )
        m_data->candidateBox->setVisible( m_data->candidateBoxVisible );
}

QString QskVirtualKeyboard::currentTextForKeyIndex( int keyIndex ) const
{
    auto keyData = keyDataAt( keyIndex );
    QString text = textForKey( keyData.key );
    return text;
}

void QskVirtualKeyboard::compose( int key )
{
    QGuiApplication::inputMethod()->invokeAction(
        static_cast< QInputMethod::Action >( Compose ), key );
}

void QskVirtualKeyboard::selectCandidate( int index )
{
    QGuiApplication::inputMethod()->invokeAction(
        static_cast< QInputMethod::Action >( SelectCandidate ), index );
}

void QskVirtualKeyboard::updateLocale( const QLocale& locale )
{
    switch( locale.language() )
    {
        case QLocale::Bulgarian:
            m_data->currentLayout = &qskKeyboardLayouts.bg;
            break;

        case QLocale::Czech:
            m_data->currentLayout = &qskKeyboardLayouts.cs;
            break;

        case QLocale::German:
            m_data->currentLayout = &qskKeyboardLayouts.de;
            break;

        case QLocale::Danish:
            m_data->currentLayout = &qskKeyboardLayouts.da;
            break;

        case QLocale::Greek:
            m_data->currentLayout = &qskKeyboardLayouts.el;
            break;

        case QLocale::English:
        {
            switch( locale.country() )
            {
                case QLocale::Canada:
                case QLocale::UnitedStates:
                case QLocale::UnitedStatesMinorOutlyingIslands:
                case QLocale::UnitedStatesVirginIslands:
                    m_data->currentLayout = &qskKeyboardLayouts.en_US;
                    break;

                default:
                    m_data->currentLayout = &qskKeyboardLayouts.en_GB;
                    break;
            }

            break;
        }

        case QLocale::Spanish:
            m_data->currentLayout = &qskKeyboardLayouts.es;
            break;

        case QLocale::Finnish:
            m_data->currentLayout = &qskKeyboardLayouts.fi;
            break;

        case QLocale::French:
            m_data->currentLayout = &qskKeyboardLayouts.fr;
            break;

        case QLocale::Hungarian:
            m_data->currentLayout = &qskKeyboardLayouts.hu;
            break;

        case QLocale::Italian:
            m_data->currentLayout = &qskKeyboardLayouts.it;
            break;

        case QLocale::Japanese:
            m_data->currentLayout = &qskKeyboardLayouts.ja;
            break;

        case QLocale::Latvian:
            m_data->currentLayout = &qskKeyboardLayouts.lv;
            break;

        case QLocale::Lithuanian:
            m_data->currentLayout = &qskKeyboardLayouts.lt;
            break;

        case QLocale::Dutch:
            m_data->currentLayout = &qskKeyboardLayouts.nl;
            break;

        case QLocale::Portuguese:
            m_data->currentLayout = &qskKeyboardLayouts.pt;
            break;

        case QLocale::Romanian:
            m_data->currentLayout = &qskKeyboardLayouts.ro;
            break;

        case QLocale::Russia:
            m_data->currentLayout = &qskKeyboardLayouts.ru;
            break;

        case QLocale::Slovenian:
            m_data->currentLayout = &qskKeyboardLayouts.sl;
            break;

        case QLocale::Slovak:
            m_data->currentLayout = &qskKeyboardLayouts.sk;
            break;

        case QLocale::Turkish:
            m_data->currentLayout = &qskKeyboardLayouts.tr;
            break;

        case QLocale::Chinese:
            m_data->currentLayout = &qskKeyboardLayouts.zh;
            break;
#if 1
        case QLocale::C:
            m_data->currentLayout = &qskKeyboardLayouts.en_US;
            break;
#endif
        default:
            qWarning() << "QskInputPanel: unsupported locale:" << locale;
            m_data->currentLayout = &qskKeyboardLayouts.en_US;

    }

    Q_EMIT displayLanguageNameChanged();

    updateKeyData();
    setMode( LowercaseMode );
}

void QskVirtualKeyboard::updateKeyData()
{
    // Key data is in normalized coordinates
    const auto keyHeight = 1.0f / RowCount;

    for( const auto& keyLayout : *m_data->currentLayout )
    {
        auto& keyDataLayout = m_data->keyTable[ &keyLayout - *m_data->currentLayout ];
        qreal yPos = 0;

        for( int i = 0; i < RowCount; i++ )
        {
            auto& row = keyLayout.data[i];
            auto& keyDataRow = keyDataLayout.data[ i ];

            const auto baseKeyWidth = 1.0 / qskRowStretch( row );

            qreal xPos = 0;
            qreal keyWidth = baseKeyWidth;

            for( const auto& key : row )
            {
                auto& keyData = keyDataRow[ &key - row ];
                keyData.key = key;

                keyWidth = baseKeyWidth * qskKeyStretch( key );
                keyData.rect = { xPos, yPos, keyWidth, keyHeight };
                xPos += keyWidth;
            }

            yPos += keyHeight;
        }
    }
}

void QskVirtualKeyboard::setMode( QskVirtualKeyboard::Mode mode )
{
    m_data->mode = mode;
    Q_EMIT modeChanged( m_data->mode );
}

bool QskVirtualKeyboard::eventFilter( QObject* object, QEvent* event )
{
    if ( event->type() == QEvent::InputMethodQuery )
    {
        /*
            Qt/Quick expects that the item associated with the virtual keyboard
            always has the focus. But you also find systems, where you have to
            navigate and select inside the virtual keyboard.
            So we have to fix the receiver.
         */

        if ( const auto inputContext = qskInputContext() )
        {
            QQuickItem* item = nullptr;

            if ( QMetaObject::invokeMethod( inputContext, "inputItem",
                Qt::DirectConnection, Q_RETURN_ARG( QQuickItem*, item ) ) )
            {
                if ( item )
                    QGuiApplication::sendEvent( item, event );
            }
        }

        return true;
    }

    return Inherited::eventFilter( object, event );
}

#include "moc_QskVirtualKeyboard.cpp"