qqmlpreviewposition.cpp

Enable keyboard shortcuts

// Copyright (C) 2018 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

// Qt-Security score:significant

#include "qqmlpreviewposition.h"

#include <QtCore/qiodevice.h>

#include <QtGui/qwindow.h>

#include <QtGui/qscreen.h>

#include <QtGui/qguiapplication.h>

#include <QtCore/QIODevice>

#include <private/qhighdpiscaling_p.h>

QT_BEGIN_NAMESPACE

static QList<QQmlPreviewPosition::ScreenData> initScreensData()

    QList<QQmlPreviewPosition::ScreenData> screensData;

    for (QScreen *screen : QGuiApplication::screens()) {

        QQmlPreviewPosition::ScreenData sd{screen->name(), screen->geometry()};

        screensData.append(sd);

    return screensData;

static QScreen *findScreen(const QString &nameOfScreen)

    for (QScreen *screen : QGuiApplication::screens()) {

        if (screen->name() == nameOfScreen)

            return screen;

    return nullptr;

static QDataStream &operator<<(QDataStream &out, const QQmlPreviewPosition::ScreenData &screenData)

    out << screenData.name;

    out << screenData.rect;

    return out;

static QDataStream &operator>>(QDataStream &in, QQmlPreviewPosition::ScreenData &screenData)

    in >> screenData.name;

    in >> screenData.rect;

    return in;

bool QQmlPreviewPosition::ScreenData::operator==(const QQmlPreviewPosition::ScreenData &other) const

    return other.rect == rect && other.name == name;

QQmlPreviewPosition::QQmlPreviewPosition()

    : m_settings("QtProject", "QtQmlPreview")

    m_savePositionTimer.setSingleShot(true);

    m_savePositionTimer.setInterval(500);

    QObject::connect(&m_savePositionTimer, &QTimer::timeout, &m_savePositionTimer, [this]() {

        saveWindowPosition();

});

QQmlPreviewPosition::~QQmlPreviewPosition()

void QQmlPreviewPosition::takePosition(QWindow *window, InitializeState state)

    Q_ASSERT(window);

    // only save the position if we already tried to get the last saved position

    if (m_initializeState == PositionInitialized) {

        m_hasPosition = true;

        auto screen = window->screen();

        auto nativePosition = QHighDpiScaling::mapPositionToNative(window->framePosition(),

                                                                   screen->handle());

        m_lastWindowPosition = { screen->name(), nativePosition, window->size() };

        m_savePositionTimer.start();

    if (state == InitializePosition)

        m_initializeState = InitializePosition;

void QQmlPreviewPosition::saveWindowPosition()

    if (m_hasPosition) {

        const QByteArray positionAsByteArray = fromPositionToByteArray(m_lastWindowPosition);

        if (!m_settingsKey.isNull())

            m_settings.setValue(m_settingsKey, positionAsByteArray);

        m_settings.setValue(QLatin1String("global_lastpostion"), positionAsByteArray);

void QQmlPreviewPosition::loadWindowPositionSettings(const QUrl &url)

    m_settingsKey = url.toString(QUrl::PreferLocalFile) + QLatin1String("_lastpostion");

    if (m_settings.contains(m_settingsKey)) {

        m_hasPosition = true;

        readLastPositionFromByteArray(m_settings.value(m_settingsKey).toByteArray());

void QQmlPreviewPosition::initLastSavedWindowPosition(QWindow *window)

    Q_ASSERT(window);

    m_initializeState = PositionInitialized;

    if (m_currentInitScreensData.isEmpty())

        m_currentInitScreensData = initScreensData();

    // if it is the first time we just use the fall back from a last shown qml file

    if (!m_hasPosition) {

        if (!m_settings.contains(QLatin1String("global_lastpostion")))

            return;

        readLastPositionFromByteArray(m_settings.value(QLatin1String("global_lastpostion"))

                                              .toByteArray());

    setPosition(m_lastWindowPosition, window);

QByteArray QQmlPreviewPosition::fromPositionToByteArray(

        const QQmlPreviewPosition::Position &position)

    QByteArray array;

    QDataStream stream(&array, QIODevice::WriteOnly);

    stream.setVersion(QDataStream::Qt_5_12);

    const quint16 majorVersion = 1;

    const quint16 minorVersion = 0;

    stream << majorVersion << minorVersion << m_currentInitScreensData << position.screenName

           << position.nativePosition << position.size;

    return array;

void QQmlPreviewPosition::readLastPositionFromByteArray(const QByteArray &array)

    QDataStream stream(array);

    stream.setVersion(QDataStream::Qt_5_12);

    // no version check for 1.0

    //const quint16 currentMajorVersion = 1;

    quint16 majorVersion = 0;

    quint16 minorVersion = 0;

    stream >> majorVersion >> minorVersion;

    QList<ScreenData> initScreensData;

    stream >> initScreensData;

    if (m_currentInitScreensData != initScreensData)

        return;

    QString nameOfScreen;

    stream >> nameOfScreen;

    QScreen *screen = findScreen(nameOfScreen);

    if (!screen)

        return;

    QPoint nativePosition;

    stream >> nativePosition;

    QSize size;

    stream >> size;

    m_lastWindowPosition = { nameOfScreen, nativePosition, size };

void QQmlPreviewPosition::setPosition(const QQmlPreviewPosition::Position &position,

                                      QWindow *window)

    if (QScreen *screen = findScreen(position.screenName)) {

        window->setScreen(screen);

        const auto point = QHighDpiScaling::mapPositionFromNative(position.nativePosition,

                                                                  screen->handle());

        const QRect geometry(point, position.size);

        if (screen->virtualGeometry().contains(geometry))

            window->setFramePosition(point);

        else

            qWarning("preview position is out of screen");

QT_END_NAMESPACE