source: trunk/src/gui/painting/qpathclipper_p.h@ 856

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#ifndef QPATHCLIPPER_P_H
#define QPATHCLIPPER_P_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 <QtGui/qpainterpath.h>
#include <QtCore/qlist.h>

#include <private/qbezier_p.h>
#include <private/qdatabuffer_p.h>
#include <stdio.h>

QT_BEGIN_HEADER

QT_BEGIN_NAMESPACE

QT_MODULE(Gui)

class QWingedEdge;

class Q_AUTOTEST_EXPORT QPathClipper
{
public:
    enum Operation {
        BoolAnd,
        BoolOr,
        BoolSub,
        Simplify
    };
public:
    QPathClipper(const QPainterPath &subject,
                 const QPainterPath &clip);

    QPainterPath clip(Operation op = BoolAnd);

    bool intersect();
    bool contains();

    static bool pathToRect(const QPainterPath &path, QRectF *rect = 0);
    static QPainterPath intersect(const QPainterPath &path, const QRectF &rect);

private:
    Q_DISABLE_COPY(QPathClipper)

    enum ClipperMode {
        ClipMode, // do the full clip
        CheckMode // for contains/intersects (only interested in whether the result path is non-empty)
    };

    bool handleCrossingEdges(QWingedEdge &list, qreal y, ClipperMode mode);
    bool doClip(QWingedEdge &list, ClipperMode mode);

    QPainterPath subjectPath;
    QPainterPath clipPath;
    Operation op;

    int aMask;
    int bMask;
};

struct QPathVertex
{
public:
    QPathVertex(const QPointF &p = QPointF(), int e = -1);
    operator QPointF() const;

    int edge;

    qreal x;
    qreal y;
};

class QPathEdge
{
public:
    enum Traversal {
        RightTraversal,
        LeftTraversal
    };

    enum Direction {
        Forward,
        Backward
    };

    enum Type {
        Line,
        Curve
    };

    QPathEdge(int a = -1, int b = -1);

    mutable int flag;

    int windingA;
    int windingB;

    int first;
    int second;

    double angle;
    double invAngle;

    int next(Traversal traversal, Direction direction) const;

    void setNext(Traversal traversal, Direction direction, int next);
    void setNext(Direction direction, int next);

    Direction directionTo(int vertex) const;
    int vertex(Direction direction) const;

private:
    int m_next[2][2];
};

class QPathSegments
{
public:
    struct Intersection {
        int vertex;
        qreal t;

        int next;

        bool operator<(const Intersection &o) const {
            return t < o.t;
        }
    };

    struct Segment {
        Segment(int pathId, int vertexA, int vertexB)
            : path(pathId)
            , va(vertexA)
            , vb(vertexB)
            , intersection(-1)
        {
        }

        int path;

        // vertices
        int va;
        int vb;

        // intersection index
        int intersection;

        QRectF bounds;
    };


    QPathSegments(int reserve);

    void setPath(const QPainterPath &path);
    void addPath(const QPainterPath &path);

    int intersections() const;
    int segments() const;
    int points() const;

    const Segment &segmentAt(int index) const;
    const QLineF lineAt(int index) const;
    const QRectF &elementBounds(int index) const;
    int pathId(int index) const;

    const QPointF &pointAt(int vertex) const;
    int addPoint(const QPointF &point);

    const Intersection *intersectionAt(int index) const;
    void addIntersection(int index, const Intersection &intersection);

    void mergePoints();

private:
    QDataBuffer<QPointF> m_points;
    QDataBuffer<Segment> m_segments;
    QDataBuffer<Intersection> m_intersections;

    int m_pathId;
};

class Q_AUTOTEST_EXPORT QWingedEdge
{
public:
    struct TraversalStatus
    {
        int edge;
        QPathEdge::Traversal traversal;
        QPathEdge::Direction direction;

        void flipDirection();
        void flipTraversal();

        void flip();
    };

    QWingedEdge();
    QWingedEdge(const QPainterPath &subject, const QPainterPath &clip);

    void simplify();