ClipPainter.cpp

// SPDX-License-Identifier: LGPL-2.1-or-later
//
// SPDX-FileCopyrightText: 2006-2009 Torsten Rahn <tackat@kde.org>
// SPDX-FileCopyrightText: 2007 Inge Wallin <ingwa@kde.org>
//
 
#include "ClipPainter.h"
 
#include <cmath>
 
#include "MarbleDebug.h"
 
namespace Marble
{
 
class ClipPainterPrivate
{
public:
    explicit ClipPainterPrivate(ClipPainter *parent);
 
    ClipPainter *q;
 
    // true if clipping is on.
    bool m_doClip;
 
    // The limits
    qreal m_left;
    qreal m_right;
    qreal m_top;
    qreal m_bottom;
 
    // Used in the paint process of vectors..
    int m_currentSector;
    int m_previousSector;
 
    //  int m_debugNodeCount;
 
    QPointF m_currentPoint;
    QPointF m_previousPoint;
 
    inline int sector(const QPointF &point) const;
 
    inline QPointF clipTop(qreal m, const QPointF &point) const;
    inline QPointF clipLeft(qreal m, const QPointF &point) const;
    inline QPointF clipBottom(qreal m, const QPointF &point) const;
    inline QPointF clipRight(qreal m, const QPointF &point) const;
 
    inline void initClipRect();
 
    inline void clipPolyObject(const QPolygonF &sourcePolygon, QList<QPolygonF> &clippedPolyObjects, bool isClosed);
 
    inline void clipMultiple(QPolygonF &clippedPolyObject, QList<QPolygonF> &clippedPolyObjects, bool isClosed);
    inline void clipOnce(QPolygonF &clippedPolyObject, QList<QPolygonF> &clippedPolyObjects, bool isClosed);
    inline void
    clipOnceCorner(QPolygonF &clippedPolyObject, QList<QPolygonF> &clippedPolyObjects, const QPointF &corner, const QPointF &point, bool isClosed) const;
    inline void clipOnceEdge(QPolygonF &clippedPolyObject, QList<QPolygonF> &clippedPolyObjects, const QPointF &point, bool isClosed) const;
 
    void labelPosition(const QPolygonF &polygon, QList<QPointF> &labelNodes, LabelPositionFlags labelPositionFlags) const;
 
    bool pointAllowsLabel(const QPointF &point) const;
    QPointF interpolateLabelPoint(const QPointF &previousPoint, const QPointF &currentPoint, LabelPositionFlags labelPositionFlags) const;
 
    static inline qreal _m(const QPointF &start, const QPointF &end);
 
    void debugDrawNodes(const QPolygonF &);
 
    qreal m_labelAreaMargin;
 
    int m_debugPenBatchColor;
    int m_debugBrushBatchColor;
    int m_debugPolygonsLevel;
    bool m_debugBatchRender;
};
 
}
 
using namespace Marble;
 
// #define MARBLE_DEBUG
 
ClipPainter::ClipPainter(QPaintDevice *pd, bool clip)
    : QPainter(pd)
    , d(new ClipPainterPrivate(this))
{
    d->initClipRect();
 
    // m_debugNodeCount = 0;
    d->m_doClip = clip;
}
 
ClipPainter::ClipPainter()
    : d(new ClipPainterPrivate(this))
{
}
 
ClipPainter::~ClipPainter()
{
    delete d;
}
 
void ClipPainter::setScreenClip(bool enable)
{
    d->m_doClip = enable;
}
 
bool ClipPainter::hasScreenClip() const
{
    return d->m_doClip;
}
 
void ClipPainter::drawPolygon(const QPolygonF &polygon, Qt::FillRule fillRule)
{
    if (d->m_doClip) {
        d->initClipRect();
        QList<QPolygonF> clippedPolyObjects;
 
        d->clipPolyObject(polygon, clippedPolyObjects, true);
 
        for (const QPolygonF &clippedPolyObject : clippedPolyObjects) {
            if (clippedPolyObject.size() > 2) {
                // mDebug() << "Size: " << clippedPolyObject.size();
                if (d->m_debugPolygonsLevel) {
                    QBrush brush = QPainter::brush();
                    QBrush originalBrush = brush;
                    QColor color = brush.color();
                    color.setAlpha(color.alpha() * 0.75);
                    brush.setColor(color);
                    QPainter::setBrush(brush);
 
                    QPainter::drawPolygon(clippedPolyObject, fillRule);
 
                    QPainter::setBrush(originalBrush);
 
                    d->debugDrawNodes(clippedPolyObject);
                } else {
                    QPainter::drawPolygon(clippedPolyObject, fillRule);
                }
            }
        }
    } else {
        if (d->m_debugPolygonsLevel) {
            QBrush brush = QPainter::brush();
            QBrush originalBrush = brush;
            QColor color = brush.color();
            color.setAlpha(color.alpha() * 0.75);
            brush.setColor(color);
            QPainter::setBrush(brush);
 
            QPainter::drawPolygon(polygon, fillRule);
 
            QPainter::setBrush(originalBrush);
 
            d->debugDrawNodes(polygon);
        } else {
            QPainter::drawPolygon(polygon, fillRule);
        }
    }
}
 
void ClipPainter::drawPolyline(const QPolygonF &polygon)
{
    if (d->m_doClip) {
        d->initClipRect();
        QList<QPolygonF> clippedPolyObjects;
 
        d->clipPolyObject(polygon, clippedPolyObjects, false);
 
        for (const QPolygonF &clippedPolyObject : clippedPolyObjects) {
            if (clippedPolyObject.size() > 1) {
                if (d->m_debugPolygonsLevel) {
                    QPen pen = QPainter::pen();
                    QPen originalPen = pen;
                    QColor color = pen.color();
                    color.setAlpha(color.alpha() * 0.75);
                    pen.setColor(color);
                    QPainter::setPen(pen);
 
                    QPainter::drawPolyline(clippedPolyObject);
 
                    QPainter::setPen(originalPen);
 
                    d->debugDrawNodes(clippedPolyObject);
                } else {
                    QPainter::drawPolyline(clippedPolyObject);
                }
            }
        }
    } else {
        if (d->m_debugPolygonsLevel) {
            QPen pen = QPainter::pen();
            QPen originalPen = pen;
            QColor color = pen.color();
            color.setAlpha(color.alpha() * 0.75);
            pen.setColor(color);
            QPainter::setPen(pen);
 
            QPainter::drawPolyline(polygon);
 
            QPainter::setPen(originalPen);
 
            d->debugDrawNodes(polygon);
        } else {
            QPainter::drawPolyline(polygon);
        }
    }
}
 
void ClipPainter::drawPolyline(const QPolygonF &polygon, QList<QPointF> &labelNodes, LabelPositionFlags positionFlags)
{
    if (d->m_doClip) {
        d->initClipRect();
        QList<QPolygonF> clippedPolyObjects;
 
        d->clipPolyObject(polygon, clippedPolyObjects, false);
 
        for (const QPolygonF &clippedPolyObject : clippedPolyObjects) {
            if (d->m_debugPolygonsLevel) {
                QPen pen = QPainter::pen();
                QPen originalPen = pen;
                QColor color = pen.color();
                color.setAlpha(color.alpha() * 0.75);
                pen.setColor(color);
                QPainter::setPen(pen);
 
                QPainter::drawPolyline(clippedPolyObject);
 
                QPainter::setPen(originalPen);
 
                d->debugDrawNodes(clippedPolyObject);
            } else {
                QPainter::drawPolyline(clippedPolyObject);
            }
        }
    } else {
        if (d->m_debugPolygonsLevel) {
            QPen pen = QPainter::pen();
            QPen originalPen = pen;
            QColor color = pen.color();
            color.setAlpha(color.alpha() * 0.75);
            pen.setColor(color);
            QPainter::setPen(pen);
 
            QPainter::drawPolyline(polygon);
 
            QPainter::setPen(originalPen);
 
            d->debugDrawNodes(polygon);
        } else {
            QPainter::drawPolyline(polygon);
        }
 
        d->labelPosition(polygon, labelNodes, positionFlags);
    }
}
 
void ClipPainter::labelPosition(const QPolygonF &polygon, QList<QPointF> &labelNodes, LabelPositionFlags labelPositionFlags) const
{
    d->labelPosition(polygon, labelNodes, labelPositionFlags);
}
 
void ClipPainter::setPen(const QColor &color)
{
    if (d->m_debugBatchRender) {
        qDebug();
    }
    setPen(QPen(color));
}
 
void ClipPainter::setPen(Qt::PenStyle style)
{
    if (d->m_debugBatchRender) {
        qDebug();
    }
    setPen(QPen(style));
}
 
void ClipPainter::setPen(const QPen &pen)
{
    if (d->m_debugBatchRender) {
        qDebug();
        if (pen != QPainter::pen()) {
            qDebug() << "--" << pen.color() << QPainter::pen().color();
            QPen newPen = pen;
            newPen.setColor((Qt::GlobalColor)(d->m_debugPenBatchColor + 4));
            QPainter::setPen(newPen);
            d->m_debugPenBatchColor++;
            d->m_debugPenBatchColor %= 14;
        } else {
            qDebug() << "++";
            QPainter::setPen(pen);
        }
    } else {
        QPainter::setPen(pen);
    }
}
 
void ClipPainter::setBrush(const QBrush &brush)
{
    if (d->m_debugBatchRender) {
        qDebug();
        if (brush != QPainter::brush()) {
            qDebug() << "--" << brush.color() << QPainter::brush().color();
            QBrush batchColor(QColor((Qt::GlobalColor)(d->m_debugBrushBatchColor)));
            QPainter::setBrush(batchColor);
            d->m_debugBrushBatchColor++;
            d->m_debugBrushBatchColor %= 20;
        } else {
            qDebug() << "++";
            QPainter::setBrush(brush);
        }
    } else {
        QPainter::setBrush(brush);
    }
}
 
void ClipPainterPrivate::labelPosition(const QPolygonF &polygon, QList<QPointF> &labelNodes, LabelPositionFlags labelPositionFlags) const
{
    if (labelPositionFlags.testFlag(LineCenter)) {
        // The Label at the center of the polyline:
        if (!polygon.isEmpty()) {
            const int labelPosition = polygon.size() / 2; // implied: 0 <= labelPosition < polygon.size()
            labelNodes << polygon.at(labelPosition);
        }
    }
 
    if (!polygon.isEmpty() && labelPositionFlags.testFlag(LineStart)) {
        if (pointAllowsLabel(polygon.first())) {
            labelNodes << polygon.first();
        }
 
        // The Label at the start of the polyline:
        for (int it = 1; it < polygon.size(); ++it) {
            const bool currentAllowsLabel = pointAllowsLabel(polygon.at(it));
 
            if (currentAllowsLabel) {
                // As polygon.size() > 0 it's ensured that it-1 exists.
                QPointF node = interpolateLabelPoint(polygon.at(it - 1), polygon.at(it), labelPositionFlags);
                if (node != QPointF(-1.0, -1.0)) {
                    labelNodes << node;
                }
                break;
            }
        }
    }
 
    if (polygon.size() > 1 && labelPositionFlags.testFlag(LineEnd)) {
        if (pointAllowsLabel(polygon.at(polygon.size() - 1))) {
            labelNodes << polygon.at(polygon.size() - 1);
        }
 
        // The Label at the end of the polyline:
        for (int it = polygon.size() - 2; it > 0; --it) {
            const bool currentAllowsLabel = pointAllowsLabel(polygon.at(it));
 
            if (currentAllowsLabel) {
                QPointF node = interpolateLabelPoint(polygon.at(it + 1), polygon.at(it), labelPositionFlags);
                if (node != QPointF(-1.0, -1.0)) {
                    labelNodes << node;
                }
                break;
            }
        }
    }
}
 
bool ClipPainterPrivate::pointAllowsLabel(const QPointF &point) const
{
    return point.x() > m_labelAreaMargin && point.x() < q->viewport().width() - m_labelAreaMargin && point.y() > m_labelAreaMargin
        && point.y() < q->viewport().height() - m_labelAreaMargin;
}
 
QPointF ClipPainterPrivate::interpolateLabelPoint(const QPointF &previousPoint, const QPointF &currentPoint, LabelPositionFlags labelPositionFlags) const
{
    qreal m = _m(previousPoint, currentPoint);
    if (previousPoint.x() <= m_labelAreaMargin) {
        if (labelPositionFlags.testFlag(IgnoreXMargin)) {
            return {-1.0, -1.0};
        }
        return {m_labelAreaMargin, previousPoint.y() + (m_labelAreaMargin - previousPoint.x()) * m};
    } else if (previousPoint.x() >= q->viewport().width() - m_labelAreaMargin) {
        if (labelPositionFlags.testFlag(IgnoreXMargin)) {
            return {-1.0, -1.0};
        }
        return {q->viewport().width() - m_labelAreaMargin, previousPoint.y() - (previousPoint.x() - q->viewport().width() + m_labelAreaMargin) * m};
    }
 
    if (previousPoint.y() <= m_labelAreaMargin) {
        if (labelPositionFlags.testFlag(IgnoreYMargin)) {
            return {-1.0, -1.0};
        }
        return {previousPoint.x() + (m_labelAreaMargin - previousPoint.y()) / m, m_labelAreaMargin};
    } else if (previousPoint.y() >= q->viewport().height() - m_labelAreaMargin) {
        if (labelPositionFlags.testFlag(IgnoreYMargin)) {
            return {-1.0, -1.0};
        }
        return {previousPoint.x() - (previousPoint.y() - q->viewport().height() + m_labelAreaMargin) / m, q->viewport().height() - m_labelAreaMargin};
    }
 
    //    mDebug() << "Previous and current node position are allowed!";
 
    return {-1.0, -1.0};
}
 
ClipPainterPrivate::ClipPainterPrivate(ClipPainter *parent)
    : m_doClip(true)
    , m_left(0.0)
    , m_right(0.0)
    , m_top(0.0)
    , m_bottom(0.0)
    , m_currentSector(4)
    , m_previousSector(4)
    , m_currentPoint(QPointF())
    , m_previousPoint(QPointF())
    , m_labelAreaMargin(10.0)
    , m_debugPenBatchColor(0)
    , m_debugBrushBatchColor(0)
    , m_debugPolygonsLevel(0)
    , m_debugBatchRender(false)
{
    q = parent;
}
 
void ClipPainterPrivate::initClipRect()
{
    qreal penHalfWidth = q->pen().widthF() / 2.0 + 1.0;
 
    m_left = -penHalfWidth;
    m_right = (qreal)(q->device()->width()) + penHalfWidth;
    m_top = -penHalfWidth;
    m_bottom = (qreal)(q->device()->height()) + penHalfWidth;
}
 
qreal ClipPainterPrivate::_m(const QPointF &start, const QPointF &end)
{
    qreal divisor = end.x() - start.x();
    if (std::fabs(divisor) < 0.000001) {
        // this is in screencoordinates so the difference
        // between 0, 0.000001 and -0.000001 isn't visible at all
        divisor = 0.000001;
    }
 
    return (end.y() - start.y()) / divisor;
}
 
QPointF ClipPainterPrivate::clipTop(qreal m, const QPointF &point) const
{
    return {(m_top - point.y()) / m + point.x(), m_top};
}
 
QPointF ClipPainterPrivate::clipLeft(qreal m, const QPointF &point) const
{
    return {m_left, (m_left - point.x()) * m + point.y()};
}
 
QPointF ClipPainterPrivate::clipBottom(qreal m, const QPointF &point) const
{
    return {(m_bottom - point.y()) / m + point.x(), m_bottom};
}
 
QPointF ClipPainterPrivate::clipRight(qreal m, const QPointF &point) const
{
    return {m_right, (m_right - point.x()) * m + point.y()};
}
 
int ClipPainterPrivate::sector(const QPointF &point) const
{
    // If we think of the image borders as (infinitely long) parallel
    // lines then the plane is divided into 9 sectors.  Each of these
    // sections is identified by a unique keynumber (currentSector):
    //
    //  0 | 1 | 2
    //  --+---+--
    //  3 | 4 | 5 <- sector number "4" represents the onscreen sector / viewport
    //  --+---+--
    //  6 | 7 | 8
    //
 
    // Figure out the section of the current point.
    int xSector = 1;
    if (point.x() < m_left)
        xSector = 0;
    else if (point.x() > m_right)
        xSector = 2;
 
    int ySector = 3;
    if (point.y() < m_top)
        ySector = 0;
    else if (point.y() > m_bottom)
        ySector = 6;
 
    // By adding xSector and ySector we get a
    // sector number of the values shown in the ASCII-art graph above.
    return ySector + xSector;
}
 
void ClipPainterPrivate::clipPolyObject(const QPolygonF &polygon, QList<QPolygonF> &clippedPolyObjects, bool isClosed)
{
    //  mDebug() << "ClipPainter enabled." ;
 
    // Only create a new polyObject as soon as we know for sure that
    // the current point is on the screen.
    QPolygonF clippedPolyObject = QPolygonF();
 
    const QList<QPointF>::const_iterator itStartPoint = polygon.constBegin();
    const QList<QPointF>::const_iterator itEndPoint = polygon.constEnd();
    QList<QPointF>::const_iterator itPoint = itStartPoint;
 
    // We use a while loop to be able to cover linestrings as well as linear rings:
    // Linear rings require to tessellate the path from the last node to the first node
    // which isn't really convenient to achieve with a for loop ...
 
    bool processingLastNode = false;
 
    while (itPoint != itEndPoint) {
        m_currentPoint = (*itPoint);
        // mDebug() << "m_currentPoint.x()" << m_currentPoint.x() << "m_currentPOint.y()" << m_currentPoint.y();
 
        // Figure out the sector of the current point.
        m_currentSector = sector(m_currentPoint);
 
        // Initialize the variables related to the previous point.
        if (itPoint == itStartPoint && processingLastNode == false) {
            if (isClosed) {
                m_previousPoint = polygon.last();
 
                // Figure out the sector of the previous point.
                m_previousSector = sector(m_previousPoint);
            } else {
                m_previousSector = m_currentSector;
            }
        }
 
        // If the current point reaches a new sector, take care of clipping.
        if (m_currentSector != m_previousSector) {
            if (m_currentSector == 4 || m_previousSector == 4) {
                // In this case the current or the previous point is visible on the
                // screen but not both. Hence we only need to clip once and require
                // only one interpolation for both cases.
 
                clipOnce(clippedPolyObject, clippedPolyObjects, isClosed);
            } else {
                // This case mostly deals with lines that reach from one
                // sector that is located off screen to another one that
                // is located off screen. In this situation the line
                // can get clipped once, twice, or not at all.
                clipMultiple(clippedPolyObject, clippedPolyObjects, isClosed);
            }
 
            m_previousSector = m_currentSector;
        }
 
        // If the current point is onscreen, just add it to our final polygon.
        if (m_currentSector == 4) {
            clippedPolyObject << m_currentPoint;
#ifdef MARBLE_DEBUG
            ++(m_debugNodeCount);
#endif
        }
 
        m_previousPoint = m_currentPoint;
 
        // Now let's handle the case where we have a (closed) polygon and where the
        // last point of the polyline is outside the viewport and the start point
        // is inside the viewport. This needs special treatment
        if (processingLastNode) {
            break;
        }
        ++itPoint;
 
        if (itPoint == itEndPoint && isClosed) {
            itPoint = itStartPoint;
            processingLastNode = true;
        }
    }
 
    // Only add the pointer if there's node data available.
    if (!clippedPolyObject.isEmpty()) {
        clippedPolyObjects << clippedPolyObject;
    }
}
 
void ClipPainterPrivate::clipMultiple(QPolygonF &clippedPolyObject, QList<QPolygonF> &clippedPolyObjects, bool isClosed)
{
    Q_UNUSED(clippedPolyObjects)
    Q_UNUSED(isClosed)
 
    // Take care of adding nodes in the image corners if the iterator
    // traverses off screen sections.
 
    qreal m = _m(m_previousPoint, m_currentPoint);
 
    switch (m_currentSector) {
    case 0:
        if (m_previousSector == 5) {
            QPointF pointRight = clipRight(m, m_previousPoint);
            QPointF pointTop = clipTop(m, m_currentPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
 
            if (pointRight.y() > m_top) {
                clippedPolyObject << pointRight;
            } else {
                clippedPolyObject << QPointF(m_right, m_top);
            }
            if (pointTop.x() >= m_left && pointTop.x() < m_right)
                clippedPolyObject << pointTop;
            if (pointLeft.y() > m_top)
                clippedPolyObject << pointLeft;
        } else if (m_previousSector == 7) {
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointTop = clipTop(m, m_currentPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
 
            if (pointBottom.x() > m_left) {
                clippedPolyObject << pointBottom;
            } else {
                clippedPolyObject << QPointF(m_left, m_bottom);
            }
            if (pointLeft.y() >= m_top && pointLeft.y() < m_bottom)
                clippedPolyObject << pointLeft;
            if (pointTop.x() > m_left)
                clippedPolyObject << pointTop;
        } else if (m_previousSector == 8) {
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointRight = clipRight(m, m_previousPoint);
            QPointF pointTop = clipTop(m, m_currentPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
 
            if (pointBottom.x() > m_left && pointBottom.x() < m_right)
                clippedPolyObject << pointBottom;
            if (pointRight.y() > m_top && pointRight.y() < m_bottom)
                clippedPolyObject << pointRight;
            if (pointTop.x() > m_left && pointTop.x() < m_right)
                clippedPolyObject << pointTop;
            if (pointLeft.y() > m_top && pointLeft.y() < m_bottom)
                clippedPolyObject << pointLeft;
 
            if (pointBottom.x() <= m_left && pointLeft.y() >= m_bottom)
                clippedPolyObject << QPointF(m_left, m_bottom);
            if (pointTop.x() >= m_right && pointRight.y() <= m_top)
                clippedPolyObject << QPointF(m_right, m_top);
        }
 
        clippedPolyObject << QPointF(m_left, m_top);
        break;
 
    case 1:
        if (m_previousSector == 3) {
            QPointF pointLeft = clipLeft(m, m_previousPoint);
            QPointF pointTop = clipTop(m, m_currentPoint);
 
            if (pointLeft.y() > m_top) {
                clippedPolyObject << pointLeft;
            } else {
                clippedPolyObject << QPointF(m_left, m_top);
            }
            if (pointTop.x() > m_left)
                clippedPolyObject << pointTop;
        } else if (m_previousSector == 5) {
            QPointF pointRight = clipRight(m, m_previousPoint);
            QPointF pointTop = clipTop(m, m_currentPoint);
 
            if (pointRight.y() > m_top) {
                clippedPolyObject << pointRight;
            } else {
                clippedPolyObject << QPointF(m_right, m_top);
            }
            if (pointTop.x() < m_right)
                clippedPolyObject << pointTop;
        } else if (m_previousSector == 6) {
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointLeft = clipLeft(m, m_previousPoint);
            QPointF pointTop = clipTop(m, m_currentPoint);
 
            if (pointBottom.x() > m_left)
                clippedPolyObject << pointBottom;
            if (pointLeft.y() > m_top && pointLeft.y() <= m_bottom)
                clippedPolyObject << pointLeft;
            if (pointTop.x() > m_left) {
                clippedPolyObject << pointTop;
            } else {
                clippedPolyObject << QPointF(m_left, m_top);
            }
        } else if (m_previousSector == 7) {
            clippedPolyObject << clipBottom(m, m_previousPoint);
            clippedPolyObject << clipTop(m, m_currentPoint);
        } else if (m_previousSector == 8) {
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointRight = clipRight(m, m_previousPoint);
            QPointF pointTop = clipTop(m, m_currentPoint);
 
            if (pointBottom.x() < m_right)
                clippedPolyObject << pointBottom;
            if (pointRight.y() > m_top && pointRight.y() <= m_bottom)
                clippedPolyObject << pointRight;
            if (pointTop.x() < m_right) {
                clippedPolyObject << pointTop;
            } else {
                clippedPolyObject << QPointF(m_right, m_top);
            }
        }
        break;
 
    case 2:
        if (m_previousSector == 3) {
            QPointF pointLeft = clipLeft(m, m_previousPoint);
            QPointF pointTop = clipTop(m, m_currentPoint);
            QPointF pointRight = clipRight(m, m_currentPoint);
 
            if (pointLeft.y() > m_top) {
                clippedPolyObject << pointLeft;
            } else {
                clippedPolyObject << QPointF(m_left, m_top);
            }
            if (pointTop.x() > m_left && pointTop.x() <= m_right)
                clippedPolyObject << pointTop;
            if (pointRight.y() > m_top)
                clippedPolyObject << pointRight;
        } else if (m_previousSector == 7) {
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointTop = clipTop(m, m_currentPoint);
            QPointF pointRight = clipRight(m, m_currentPoint);
 
            if (pointBottom.x() < m_right) {
                clippedPolyObject << pointBottom;
            } else {
                clippedPolyObject << QPointF(m_right, m_bottom);
            }
            if (pointRight.y() >= m_top && pointRight.y() < m_bottom)
                clippedPolyObject << pointRight;
            if (pointTop.x() < m_right)
                clippedPolyObject << pointTop;
        } else if (m_previousSector == 6) {
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
            QPointF pointTop = clipTop(m, m_currentPoint);
            QPointF pointRight = clipRight(m, m_previousPoint);
 
            if (pointBottom.x() > m_left && pointBottom.x() < m_right)
                clippedPolyObject << pointBottom;
            if (pointLeft.y() > m_top && pointLeft.y() < m_bottom)
                clippedPolyObject << pointLeft;
            if (pointTop.x() > m_left && pointTop.x() < m_right)
                clippedPolyObject << pointTop;
            if (pointRight.y() > m_top && pointRight.y() < m_bottom)
                clippedPolyObject << pointRight;
 
            if (pointBottom.x() >= m_right && pointRight.y() >= m_bottom)
                clippedPolyObject << QPointF(m_right, m_bottom);
            if (pointTop.x() <= m_left && pointLeft.y() <= m_top)
                clippedPolyObject << QPointF(m_left, m_top);
        }
 
        clippedPolyObject << QPointF(m_right, m_top);
        break;
 
    case 3:
        if (m_previousSector == 7) {
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
 
            if (pointBottom.x() > m_left)
                clippedPolyObject << pointBottom;
            if (pointLeft.y() < m_bottom) {
                clippedPolyObject << pointLeft;
            } else {
                clippedPolyObject << QPointF(m_left, m_bottom);
            }
        } else if (m_previousSector == 1) {
            QPointF pointTop = clipTop(m, m_previousPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
 
            if (pointTop.x() > m_left)
                clippedPolyObject << pointTop;
            if (pointLeft.y() > m_top) {
                clippedPolyObject << pointLeft;
            } else {
                clippedPolyObject << QPointF(m_left, m_top);
            }
        } else if (m_previousSector == 8) {
            QPointF pointRight = clipRight(m, m_previousPoint);
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
 
            if (pointRight.y() < m_bottom)
                clippedPolyObject << pointRight;
            if (pointBottom.x() > m_left && pointBottom.x() <= m_right)
                clippedPolyObject << pointBottom;
            if (pointLeft.y() < m_bottom) {
                clippedPolyObject << pointLeft;
            } else {
                clippedPolyObject << QPointF(m_left, m_bottom);
            }
        } else if (m_previousSector == 5) {
            clippedPolyObject << clipRight(m, m_previousPoint);
            clippedPolyObject << clipLeft(m, m_currentPoint);
        } else if (m_previousSector == 2) {
            QPointF pointRight = clipRight(m, m_previousPoint);
            QPointF pointTop = clipTop(m, m_previousPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
 
            if (pointRight.y() > m_top)
                clippedPolyObject << pointRight;
            if (pointTop.x() > m_left && pointTop.x() <= m_right)
                clippedPolyObject << pointTop;
            if (pointLeft.y() > m_top) {
                clippedPolyObject << pointLeft;
            } else {
                clippedPolyObject << QPointF(m_left, m_top);
            }
        }
        break;
 
    case 5:
        if (m_previousSector == 7) {
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointRight = clipRight(m, m_currentPoint);
 
            if (pointBottom.x() < m_right)
                clippedPolyObject << pointBottom;
            if (pointRight.y() < m_bottom) {
                clippedPolyObject << pointRight;
            } else {
                clippedPolyObject << QPointF(m_right, m_bottom);
            }
        } else if (m_previousSector == 1) {
            QPointF pointTop = clipTop(m, m_previousPoint);
            QPointF pointRight = clipRight(m, m_currentPoint);
 
            if (pointTop.x() < m_right)
                clippedPolyObject << pointTop;
            if (pointRight.y() > m_top) {
                clippedPolyObject << pointRight;
            } else {
                clippedPolyObject << QPointF(m_right, m_top);
            }
        } else if (m_previousSector == 6) {
            QPointF pointLeft = clipLeft(m, m_previousPoint);
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointRight = clipRight(m, m_currentPoint);
 
            if (pointLeft.y() < m_bottom)
                clippedPolyObject << pointLeft;
            if (pointBottom.x() >= m_left && pointBottom.x() < m_right)
                clippedPolyObject << pointBottom;
            if (pointRight.y() < m_bottom) {
                clippedPolyObject << pointRight;
            } else {
                clippedPolyObject << QPointF(m_right, m_bottom);
            }
        } else if (m_previousSector == 3) {
            clippedPolyObject << clipLeft(m, m_previousPoint);
            clippedPolyObject << clipRight(m, m_currentPoint);
        } else if (m_previousSector == 0) {
            QPointF pointLeft = clipLeft(m, m_previousPoint);
            QPointF pointTop = clipTop(m, m_previousPoint);
            QPointF pointRight = clipRight(m, m_currentPoint);
 
            if (pointLeft.y() > m_top)
                clippedPolyObject << pointLeft;
            if (pointTop.x() >= m_left && pointTop.x() < m_right)
                clippedPolyObject << pointTop;
            if (pointRight.y() > m_top) {
                clippedPolyObject << pointRight;
            } else {
                clippedPolyObject << QPointF(m_right, m_top);
            }
        }
        break;
 
    case 6:
        if (m_previousSector == 5) {
            QPointF pointRight = clipRight(m, m_previousPoint);
            QPointF pointBottom = clipBottom(m, m_currentPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
 
            if (pointRight.y() < m_bottom) {
                clippedPolyObject << pointRight;
            } else {
                clippedPolyObject << QPointF(m_right, m_bottom);
            }
            if (pointBottom.x() >= m_left && pointBottom.x() < m_right)
                clippedPolyObject << pointBottom;
            if (pointLeft.y() < m_bottom)
                clippedPolyObject << pointLeft;
        } else if (m_previousSector == 1) {
            QPointF pointTop = clipTop(m, m_previousPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
            QPointF pointBottom = clipBottom(m, m_currentPoint);
 
            if (pointTop.x() > m_left) {
                clippedPolyObject << pointTop;
            } else {
                clippedPolyObject << QPointF(m_left, m_top);
            }
            if (pointLeft.y() > m_top && pointLeft.y() <= m_bottom)
                clippedPolyObject << pointLeft;
            if (pointBottom.x() > m_left)
                clippedPolyObject << pointBottom;
        } else if (m_previousSector == 2) {
            QPointF pointTop = clipTop(m, m_currentPoint);
            QPointF pointRight = clipRight(m, m_previousPoint);
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
 
            if (pointTop.x() > m_left && pointTop.x() < m_right)
                clippedPolyObject << pointTop;
            if (pointRight.y() > m_top && pointRight.y() < m_bottom)
                clippedPolyObject << pointRight;
            if (pointBottom.x() > m_left && pointBottom.x() < m_right)
                clippedPolyObject << pointBottom;
            if (pointLeft.y() > m_top && pointLeft.y() < m_bottom)
                clippedPolyObject << pointLeft;
 
            if (pointBottom.x() >= m_right && pointRight.y() >= m_bottom)
                clippedPolyObject << QPointF(m_right, m_bottom);
            if (pointTop.x() <= m_left && pointLeft.y() <= m_top)
                clippedPolyObject << QPointF(m_left, m_top);
        }
 
        clippedPolyObject << QPointF(m_left, m_bottom);
        break;
 
    case 7:
        if (m_previousSector == 3) {
            QPointF pointLeft = clipLeft(m, m_previousPoint);
            QPointF pointBottom = clipBottom(m, m_currentPoint);
 
            if (pointLeft.y() < m_bottom) {
                clippedPolyObject << pointLeft;
            } else {
                clippedPolyObject << QPointF(m_left, m_bottom);
            }
            if (pointBottom.x() > m_left)
                clippedPolyObject << pointBottom;
        } else if (m_previousSector == 5) {
            QPointF pointRight = clipRight(m, m_previousPoint);
            QPointF pointBottom = clipBottom(m, m_currentPoint);
 
            if (pointRight.y() < m_bottom) {
                clippedPolyObject << pointRight;
            } else {
                clippedPolyObject << QPointF(m_right, m_bottom);
            }
            if (pointBottom.x() < m_right)
                clippedPolyObject << pointBottom;
        } else if (m_previousSector == 0) {
            QPointF pointTop = clipTop(m, m_previousPoint);
            QPointF pointLeft = clipLeft(m, m_previousPoint);
            QPointF pointBottom = clipBottom(m, m_currentPoint);
 
            if (pointTop.x() > m_left)
                clippedPolyObject << pointTop;
            if (pointLeft.y() >= m_top && pointLeft.y() < m_bottom)
                clippedPolyObject << pointLeft;
            if (pointBottom.x() > m_left) {
                clippedPolyObject << pointBottom;
            } else {
                clippedPolyObject << QPointF(m_left, m_bottom);
            }
        } else if (m_previousSector == 1) {
            clippedPolyObject << clipTop(m, m_previousPoint);
            clippedPolyObject << clipBottom(m, m_currentPoint);
        } else if (m_previousSector == 2) {
            QPointF pointTop = clipTop(m, m_previousPoint);
            QPointF pointRight = clipRight(m, m_previousPoint);
            QPointF pointBottom = clipBottom(m, m_currentPoint);
 
            if (pointTop.x() < m_right)
                clippedPolyObject << pointTop;
            if (pointRight.y() >= m_top && pointRight.y() < m_bottom)
                clippedPolyObject << pointRight;
            if (pointBottom.x() < m_right) {
                clippedPolyObject << pointBottom;
            } else {
                clippedPolyObject << QPointF(m_right, m_bottom);
            }
        }
        break;
 
    case 8:
        if (m_previousSector == 3) {
            QPointF pointLeft = clipLeft(m, m_previousPoint);
            QPointF pointBottom = clipBottom(m, m_currentPoint);
            QPointF pointRight = clipRight(m, m_currentPoint);
 
            if (pointLeft.y() < m_bottom) {
                clippedPolyObject << pointLeft;
            } else {
                clippedPolyObject << QPointF(m_left, m_bottom);
            }
            if (pointBottom.x() > m_left && pointBottom.x() <= m_right)
                clippedPolyObject << pointBottom;
            if (pointRight.y() < m_bottom)
                clippedPolyObject << pointRight;
        } else if (m_previousSector == 1) {
            QPointF pointTop = clipTop(m, m_previousPoint);
            QPointF pointRight = clipRight(m, m_currentPoint);
            QPointF pointBottom = clipBottom(m, m_currentPoint);
 
            if (pointTop.x() < m_right) {
                clippedPolyObject << pointTop;
            } else {
                clippedPolyObject << QPointF(m_right, m_top);
            }
            if (pointRight.y() > m_top && pointRight.y() <= m_bottom)
                clippedPolyObject << pointRight;
            if (pointBottom.x() < m_right)
                clippedPolyObject << pointBottom;
        } else if (m_previousSector == 0) {
            QPointF pointTop = clipTop(m, m_currentPoint);
            QPointF pointLeft = clipLeft(m, m_currentPoint);
            QPointF pointBottom = clipBottom(m, m_previousPoint);
            QPointF pointRight = clipRight(m, m_previousPoint);
 
            if (pointTop.x() > m_left && pointTop.x() < m_right)
                clippedPolyObject << pointTop;
            if (pointLeft.y() > m_top && pointLeft.y() < m_bottom)
                clippedPolyObject << pointLeft;
            if (pointBottom.x() > m_left && pointBottom.x() < m_right)
                clippedPolyObject << pointBottom;
            if (pointRight.y() > m_top && pointRight.y() < m_bottom)
                clippedPolyObject << pointRight;
 
            if (pointBottom.x() <= m_left && pointLeft.y() >= m_bottom)
                clippedPolyObject << QPointF(m_left, m_bottom);
            if (pointTop.x() >= m_right && pointRight.y() <= m_top)
                clippedPolyObject << QPointF(m_right, m_top);
        }
 
        clippedPolyObject << QPointF(m_right, m_bottom);
        break;
 
    default:
        break;
    }
}
 
void ClipPainterPrivate::clipOnceCorner(QPolygonF &clippedPolyObject,
                                        QList<QPolygonF> &clippedPolyObjects,
                                        const QPointF &corner,
                                        const QPointF &point,
                                        bool isClosed) const
{
    Q_UNUSED(clippedPolyObjects)
    Q_UNUSED(isClosed)
 
    if (m_currentSector == 4) {
        // Appearing
        clippedPolyObject << corner;
        clippedPolyObject << point;
    } else {
        // Disappearing
        clippedPolyObject << point;
        clippedPolyObject << corner;
    }
}
 
void ClipPainterPrivate::clipOnceEdge(QPolygonF &clippedPolyObject, QList<QPolygonF> &clippedPolyObjects, const QPointF &point, bool isClosed) const
{
    if (m_currentSector == 4) {
        // Appearing
        if (!isClosed) {
            clippedPolyObject = QPolygonF();
        }
        clippedPolyObject << point;
    } else {
        // Disappearing
        clippedPolyObject << point;
        if (!isClosed) {
            clippedPolyObjects << clippedPolyObject;
        }
    }
}
 
void ClipPainterPrivate::clipOnce(QPolygonF &clippedPolyObject, QList<QPolygonF> &clippedPolyObjects, bool isClosed)
{
    //  Interpolate border points (linear interpolation)
    QPointF point;
 
    // Calculating the slope.
    qreal m = _m(m_previousPoint, m_currentPoint);
 
    // Calculate in which sector the end of the line is located that is off screen
    int offscreenpos = (m_currentSector == 4) ? m_previousSector : m_currentSector;
 
    // "Rise over run" for all possible situations .
    switch (offscreenpos) {
    case 0: // topleft
        point = clipTop(m, m_previousPoint);
        if (point.x() < m_left) {
            point = clipLeft(m, point);
        }
        clipOnceCorner(clippedPolyObject, clippedPolyObjects, QPointF(m_left, m_top), point, isClosed);
        break;
    case 1: // top
        point = clipTop(m, m_previousPoint);
        clipOnceEdge(clippedPolyObject, clippedPolyObjects, point, isClosed);
        break;
    case 2: // topright
        point = clipTop(m, m_previousPoint);
        if (point.x() > m_right) {
            point = clipRight(m, point);
        }
        clipOnceCorner(clippedPolyObject, clippedPolyObjects, QPointF(m_right, m_top), point, isClosed);
        break;
    case 3: // left
        point = clipLeft(m, m_previousPoint);
        clipOnceEdge(clippedPolyObject, clippedPolyObjects, point, isClosed);
        break;
    case 5: // right
        point = clipRight(m, m_previousPoint);
        clipOnceEdge(clippedPolyObject, clippedPolyObjects, point, isClosed);
        break;
    case 6: // bottomleft
        point = clipBottom(m, m_previousPoint);
        if (point.x() < m_left) {
            point = clipLeft(m, point);
        }
        clipOnceCorner(clippedPolyObject, clippedPolyObjects, QPointF(m_left, m_bottom), point, isClosed);
        break;
    case 7: // bottom
        point = clipBottom(m, m_previousPoint);
        clipOnceEdge(clippedPolyObject, clippedPolyObjects, point, isClosed);
        break;
    case 8: // bottomright
        point = clipBottom(m, m_previousPoint);
        if (point.x() > m_right) {
            point = clipRight(m, point);
        }
        clipOnceCorner(clippedPolyObject, clippedPolyObjects, QPointF(m_right, m_bottom), point, isClosed);
        break;
    default:
        break;
    }
}
 
void ClipPainter::setDebugPolygonsLevel(int level)
{
    d->m_debugPolygonsLevel = level;
}
 
void ClipPainter::setDebugBatchRender(bool enabled)
{
    d->m_debugBatchRender = enabled;
}
 
void ClipPainterPrivate::debugDrawNodes(const QPolygonF &polygon)
{
    q->save();
    q->setRenderHint(QPainter::Antialiasing, false);
 
    q->setPen(Qt::red);
    q->setBrush(QBrush("#40FF0000"));
 
    const QList<QPointF>::const_iterator itStartPoint = polygon.constBegin();
    const QList<QPointF>::const_iterator itEndPoint = polygon.constEnd();
    QList<QPointF>::const_iterator itPoint = itStartPoint;
 
    int i = 0;
 
    for (; itPoint != itEndPoint; ++itPoint) {
        ++i;
 
        if (itPoint == itStartPoint || itPoint == itStartPoint + 1 || itPoint == itStartPoint + 2) {
            q->setPen(Qt::darkGreen);
            q->setBrush(QBrush("#4000FF00"));
            if (itPoint == itStartPoint) {
                q->drawRect(itPoint->x() - 6.0, itPoint->y() - 6.0, 12.0, 12.0);
            } else if (itPoint == itStartPoint + 1) {
                q->drawRect(itPoint->x() - 4.0, itPoint->y() - 4.0, 8.0, 8.0);
            } else {
                q->drawRect(itPoint->x() - 2.0, itPoint->y() - 2.0, 4.0, 4.0);
            }
            q->setPen(Qt::red);
            q->setBrush(QBrush("#40FF0000"));
        } else if (itPoint == itEndPoint - 1 || itPoint == itEndPoint - 2 || itPoint == itEndPoint - 3) {
            q->setPen(Qt::blue);
            q->setBrush(QBrush("#400000FF"));
            if (itPoint == itEndPoint - 3) {
                q->drawRect(itPoint->x() - 6.0, itPoint->y() - 6.0, 12.0, 12.0);
            } else if (itPoint == itEndPoint - 2) {
                q->drawRect(itPoint->x() - 4.0, itPoint->y() - 4.0, 8.0, 8.0);
            } else {
                q->drawRect(itPoint->x() - 2.0, itPoint->y() - 2.0, 4.0, 4.0);
            }
            q->setPen(Qt::red);
            q->setBrush(QBrush("#400000FF"));
        } else {
            q->drawRect(itPoint->x() - 4, itPoint->y() - 4, 8.0, 8.0);
        }
        if (m_debugPolygonsLevel == 2) {
            q->setFont(QFont(QStringLiteral("Sans Serif"), 7));
            q->setPen("black");
            q->setBrush(Qt::transparent);
            q->drawText(itPoint->x() + 6.0, itPoint->y() + (15 - (i * 5) % 30), QString::number(i));
        }
    }
    q->restore();
}