qqmlpreviewhandler.h

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// 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
 
#ifndef QQMLPREVIEWHANDLER_H
#define QQMLPREVIEWHANDLER_H
 
//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
 
#include "qqmlpreviewposition.h"
 
#include <QtCore/qobject.h>
#include <QtCore/qvector.h>
#include <QtCore/qrect.h>
#include <QtCore/qpointer.h>
#include <QtCore/qelapsedtimer.h>
#include <QtQml/qqmlengine.h>
 
QT_BEGIN_NAMESPACE
 
class QQmlEngine;
class QQuickItem;
class QQmlPreviewUrlInterceptor;
class QQuickWindow;
 
class QQmlPreviewHandler : public QObject
{
    Q_OBJECT
public:
    explicit QQmlPreviewHandler(QObject *parent = nullptr);
    ~QQmlPreviewHandler();
 
    QQuickItem *currentRootItem();
 
    void addEngine(QQmlEngine *engine);
    void removeEngine(QQmlEngine *engine);
 
    void loadUrl(const QUrl &url);
    void rerun();
    void zoom(qreal newFactor);
 
    void clear();
 
    struct FpsInfo {
        quint16 numSyncs;
        quint16 minSync;
        quint16 maxSync;
        quint16 totalSync;
 
        quint16 numRenders;
        quint16 minRender;
        quint16 maxRender;
        quint16 totalRender;
    };
 
Q_SIGNALS:
    void error(const QString &message);
    void fps(const FpsInfo &info);
 
protected:
    bool eventFilter(QObject *obj, QEvent *event) override;
private:
    void doZoom();
    void tryCreateObject();
    void showObject(QObject *object);
    void setCurrentWindow(QQuickWindow *window);
 
    void beforeSynchronizing();
    void afterSynchronizing();
    void beforeRendering();
    void frameSwapped();
 
    void fpsTimerHit();
 
    QScopedPointer<QQuickItem> m_dummyItem;
    QList<QQmlEngine *> m_engines;
    QPointer<QQuickItem> m_currentRootItem;
    QVector<QPointer<QObject>> m_createdObjects;
    QScopedPointer<QQmlComponent> m_component;
    QPointer<QQuickWindow> m_currentWindow;
    qreal m_zoomFactor = 1.0;
    bool m_supportsMultipleWindows;
    QQmlPreviewPosition m_lastPosition;
 
    QTimer m_fpsTimer;
 
    struct FrameTime {
        void beginFrame();
        void recordFrame();
        void endFrame();
        void reset();
 
        QElapsedTimer timer;
        qint64 elapsed = -1;
        quint16 min = std::numeric_limits<quint16>::max();
        quint16 max = 0;
        quint16 total = 0;
        quint16 number = 0;
    };
 
    FrameTime m_rendering;
    FrameTime m_synchronizing;
};
 
QT_END_NAMESPACE
 
Q_DECLARE_METATYPE(QQmlPreviewHandler::FpsInfo)
 
#endif // QQMLPREVIEWHANDLER_H