qpainterpath_p.h

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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
 
#ifndef QPAINTERPATH_P_H
#define QPAINTERPATH_P_H
 
//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists for the convenience
// of other Qt classes.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
 
#include <QtGui/private/qtguiglobal_p.h>
#include "QtGui/qpainterpath.h"
#include "QtGui/qregion.h"
#include "QtCore/qlist.h"
#include "QtCore/qvarlengtharray.h"
 
#include <private/qvectorpath_p.h>
#include <private/qstroker_p.h>
#include <private/qbezier_p.h>
 
#include <memory>
 
QT_BEGIN_NAMESPACE
 
class QPolygonF;
class QVectorPathConverter;
 
class QVectorPathConverter
{
public:
    QVectorPathConverter(const QList<QPainterPath::Element> &path, bool hasWindingFill, bool convex)
        : pathData(path, hasWindingFill, convex),
          path(pathData.points.data(), path.size(), pathData.elements.data(), pathData.flags)
    {
    }
 
    const QVectorPath &vectorPath() {
        return path;
    }
 
    struct QVectorPathData {
        QVectorPathData(const QList<QPainterPath::Element> &path, bool hasWindingFill, bool convex)
            : elements(path.size()), points(path.size() * 2), flags(0)
        {
            int ptsPos = 0;
            bool isLines = true;
            for (int i=0; i<path.size(); ++i) {
                const QPainterPath::Element &e = path.at(i);
                elements[i] = e.type;
                points[ptsPos++] = e.x;
                points[ptsPos++] = e.y;
                if (e.type == QPainterPath::CurveToElement)
                    flags |= QVectorPath::CurvedShapeMask;
 
                // This is to check if the path contains only alternating lineTo/moveTo,
                // in which case we can set the LinesHint in the path. MoveTo is 0 and
                // LineTo is 1 so the i%2 gets us what we want cheaply.
                isLines = isLines && e.type == (QPainterPath::ElementType) (i%2);
            }
 
            if (hasWindingFill)
                flags |= QVectorPath::WindingFill;
            else
                flags |= QVectorPath::OddEvenFill;
 
            if (isLines)
                flags |= QVectorPath::LinesShapeMask;
            else {
                flags |= QVectorPath::AreaShapeMask;
                if (!convex)
                    flags |= QVectorPath::NonConvexShapeMask;
            }
 
        }
        QVarLengthArray<QPainterPath::ElementType> elements;
        QVarLengthArray<qreal> points;
        uint flags;
    };
 
    QVectorPathData pathData;
    QVectorPath path;
 
private:
    Q_DISABLE_COPY_MOVE(QVectorPathConverter)
};
 
class QPainterPathPrivate
{
public:
    friend class QPainterPath;
    friend class QPainterPathStroker;
    friend class QPainterPathStrokerPrivate;
    friend class QTransform;
    friend class QVectorPath;
#ifndef QT_NO_DATASTREAM
    friend Q_GUI_EXPORT QDataStream &operator<<(QDataStream &, const QPainterPath &);
    friend Q_GUI_EXPORT QDataStream &operator>>(QDataStream &, QPainterPath &);
#endif
 
    QPainterPathPrivate() noexcept
        : require_moveTo(false),
          dirtyBounds(false),
          dirtyControlBounds(false),
          convex(false),
          hasWindingFill(false),
          cacheEnabled(false)
    {
    }
 
    QPainterPathPrivate(QPointF startPoint)
        : elements{ { startPoint.x(), startPoint.y(), QPainterPath::MoveToElement } },
          bounds(startPoint, QSizeF(0, 0)),
          controlBounds(startPoint, QSizeF(0, 0)),
          require_moveTo(false),
          dirtyBounds(false),
          dirtyControlBounds(false),
          convex(false),
          hasWindingFill(false),
          cacheEnabled(false)
    {
    }
 
    QPainterPathPrivate(const QPainterPathPrivate &other) noexcept
        : elements(other.elements),
          m_runLengths(other.m_runLengths),
          bounds(other.bounds),
          controlBounds(other.controlBounds),
          cStart(other.cStart),
          require_moveTo(false),
          dirtyBounds(other.dirtyBounds),
          dirtyControlBounds(other.dirtyControlBounds),
          dirtyRunLengths(other.dirtyRunLengths),
          convex(other.convex),
          hasWindingFill(other.hasWindingFill),
          cacheEnabled(other.cacheEnabled)
    {
    }
 
    QPainterPathPrivate &operator=(const QPainterPathPrivate &) = delete;
    ~QPainterPathPrivate() = default;
 
    inline bool isClosed() const;
    inline void close();
    inline void maybeMoveTo();
    inline void clear();
    QPointF endPointOfElement(int elemIdx) const;
    void computeRunLengths();
    int elementAtLength(qreal len);
    int elementAtT(qreal t);
    QBezier bezierAtT(const QPainterPath &path, qreal t, qreal *startingLength,
                      qreal *bezierLength) const;
    enum TrimFlags {
        TrimStart = 0x01,
        TrimEnd = 0x02
    };
    void appendTrimmedElement(QPainterPath *to, int elemIdx, int trimFlags, qreal startLen, qreal endLen);
    void appendStartOfElement(QPainterPath *to, int elemIdx, qreal len)
    {
        appendTrimmedElement(to, elemIdx, TrimEnd, 0, len);
    }
    void appendEndOfElement(QPainterPath *to, int elemIdx, qreal len)
    {
        appendTrimmedElement(to, elemIdx, TrimStart, len, 0);
    }
    void appendSliceOfElement(QPainterPath *to, int elemIdx, qreal fromLen, qreal toLen)
    {
        appendTrimmedElement(to, elemIdx, TrimStart | TrimEnd, fromLen, toLen);
    }
    void appendElementRange(QPainterPath *to, int first, int last);
 
    const QVectorPath &vectorPath() {
        if (!pathConverter)
            pathConverter.reset(new QVectorPathConverter(elements, hasWindingFill, convex));
        return pathConverter->path;
    }
 
private:
    QList<QPainterPath::Element> elements;
    std::unique_ptr<QVectorPathConverter> pathConverter;
    QList<qreal> m_runLengths;
    QRectF bounds;
    QRectF controlBounds;
 
    int cStart = 0;
 
    bool require_moveTo : 1;
    bool dirtyBounds : 1;
    bool dirtyControlBounds : 1;
    bool dirtyRunLengths : 1;
    bool convex : 1;
    bool hasWindingFill : 1;
    bool cacheEnabled : 1;
};
 
class QPainterPathStrokerPrivate
{
public:
    QPainterPathStrokerPrivate();
 
    QStroker stroker;
    QList<qfixed> dashPattern;
    qreal dashOffset;
};
 
inline const QPainterPath QVectorPath::convertToPainterPath() const
{
        QPainterPath path;
        path.ensureData();
        QPainterPathPrivate *data = path.d_func();
        data->elements.reserve(m_count);
        int index = 0;
        data->elements[0].x = m_points[index++];
        data->elements[0].y = m_points[index++];
 
        if (m_elements) {
            data->elements[0].type = m_elements[0];
            for (int i=1; i<m_count; ++i) {
                QPainterPath::Element element;
                element.x = m_points[index++];
                element.y = m_points[index++];
                element.type = m_elements[i];
                data->elements << element;
            }
        } else {
            data->elements[0].type = QPainterPath::MoveToElement;
            for (int i=1; i<m_count; ++i) {
                QPainterPath::Element element;
                element.x = m_points[index++];
                element.y = m_points[index++];
                element.type = QPainterPath::LineToElement;
                data->elements << element;
            }
        }
 
        data->hasWindingFill = !(m_hints & OddEvenFill);
        return path;
}
 
void Q_GUI_EXPORT qt_find_ellipse_coords(const QRectF &r, qreal angle, qreal length,
                                         QPointF* startPoint, QPointF *endPoint);
 
inline bool QPainterPathPrivate::isClosed() const
{
    const QPainterPath::Element &first = elements.at(cStart);
    const QPainterPath::Element &last = elements.last();
    return first.x == last.x && first.y == last.y;
}
 
inline void QPainterPathPrivate::close()
{
    require_moveTo = true;
    const QPainterPath::Element &first = elements.at(cStart);
    QPainterPath::Element &last = elements.last();
    if (first.x != last.x || first.y != last.y) {
        if (qFuzzyCompare(first.x, last.x) && qFuzzyCompare(first.y, last.y)) {
            last.x = first.x;
            last.y = first.y;
        } else {
            QPainterPath::Element e = { first.x, first.y, QPainterPath::LineToElement };
            elements << e;
        }
    }
}
 
inline void QPainterPathPrivate::maybeMoveTo()
{
    if (require_moveTo) {
        QPainterPath::Element e = elements.last();
        e.type = QPainterPath::MoveToElement;
        elements.append(e);
        require_moveTo = false;
    }
}
 
inline void QPainterPathPrivate::clear()
{
    elements.clear();
    m_runLengths.clear();
 
    cStart = 0;
    bounds = {};
    controlBounds = {};
 
    require_moveTo = false;
    dirtyBounds = false;
    dirtyControlBounds = false;
    dirtyRunLengths = false;
    convex = false;
 
    pathConverter.reset();
}
 
inline QPointF QPainterPathPrivate::endPointOfElement(int elemIdx) const
{
    const QPainterPath::Element &e = elements.at(elemIdx);
    if (e.isCurveTo())
        return elements.at(elemIdx + 2);
    else
        return e;
}
 
inline int QPainterPathPrivate::elementAtLength(qreal len)
{
    Q_ASSERT(cacheEnabled);
    Q_ASSERT(!dirtyRunLengths);
    const auto it = std::lower_bound(m_runLengths.constBegin(), m_runLengths.constEnd(), len);
    return (it == m_runLengths.constEnd()) ? m_runLengths.size() - 1 : int(it - m_runLengths.constBegin());
}
 
inline int QPainterPathPrivate::elementAtT(qreal t)
{
    Q_ASSERT(cacheEnabled);
    if (dirtyRunLengths)
        computeRunLengths();
    qreal len = t * m_runLengths.constLast();
    return elementAtLength(len);
}
 
#define KAPPA qreal(0.5522847498)
 
QT_END_NAMESPACE
 
#endif // QPAINTERPATH_P_H