qgraphicsanchorlayout_p.h

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#ifndef QGRAPHICSANCHORLAYOUT_P_H
#define QGRAPHICSANCHORLAYOUT_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 <QGraphicsWidget>
#include <private/qobject_p.h>

#include "qgraphicslayout_p.h"
#include "qgraphicsanchorlayout.h"
#include "qgraph_p.h"
#include "qsimplex_p.h"
#ifndef QT_NO_GRAPHICSVIEW
QT_BEGIN_NAMESPACE

/*
  The public QGraphicsAnchorLayout interface represents an anchorage point
  as a pair of a <QGraphicsLayoutItem *> and a <Qt::AnchorPoint>.

  Internally though, it has a graph of anchorage points (vertices) and
  anchors (edges), represented by the AnchorVertex and AnchorData structs
  respectively.
*/

struct AnchorVertex {
    enum Type {
        Normal = 0,
        Pair
    };

    AnchorVertex(QGraphicsLayoutItem *item, Qt::AnchorPoint edge)
        : m_item(item), m_edge(edge), m_type(Normal) {}

    AnchorVertex()
        : m_item(0), m_edge(Qt::AnchorPoint(0)), m_type(Normal) {}

#ifdef QT_DEBUG
    inline QString toString() const;
#endif

    QGraphicsLayoutItem *m_item;
    Qt::AnchorPoint m_edge;
    uint m_type : 1;

    // Current distance from this vertex to the layout edge (Left or Top)
    // Value is calculated from the current anchors sizes.
    qreal distance;
};

struct AnchorData : public QSimplexVariable {
    enum Type {
        Normal = 0,
        Sequential,
        Parallel
    };

    enum Dependency {
        Independent = 0,
        Master,
        Slave
    };

    AnchorData()
        : QSimplexVariable(), from(0), to(0),
          minSize(0), prefSize(0), maxSize(0),
          minPrefSize(0), maxPrefSize(0),
          sizeAtMinimum(0), sizeAtPreferred(0),
          sizeAtMaximum(0), item(0), graphicsAnchor(0),
          type(Normal), isLayoutAnchor(false),
          isCenterAnchor(false), orientation(0),
          dependency(Independent) {}
    virtual ~AnchorData();

    virtual void updateChildrenSizes() {}
    void refreshSizeHints(const QLayoutStyleInfo *styleInfo = 0);

#ifdef QT_DEBUG
    void dump(int indent = 2);
    inline QString toString() const;
    QString name;
#endif

    // Anchor is semantically directed
    AnchorVertex *from;
    AnchorVertex *to;

    // Nominal sizes
    // These are the intrinsic size restrictions for a given item. They are
    // used as input for the calculation of the actual sizes.
    // These values are filled by the refreshSizeHints method, based on the
    // anchor size policy, the size hints of the item it (possibly) represents
    // and the layout spacing information.
    qreal minSize;
    qreal prefSize;
    qreal maxSize;

    qreal minPrefSize;
    qreal maxPrefSize;

    // Calculated sizes
    // These attributes define which sizes should that anchor be in when the
    // layout is at its minimum, preferred or maximum sizes. Values are
    // calculated by the Simplex solver based on the current layout setup.
    qreal sizeAtMinimum;
    qreal sizeAtPreferred;
    qreal sizeAtMaximum;

    // References to the classes that represent this anchor in the public world
    // An anchor may represent a LayoutItem, it may also be acessible externally
    // through a GraphicsAnchor "handler".
    QGraphicsLayoutItem *item;
    QGraphicsAnchor *graphicsAnchor;

    uint type : 2;            // either Normal, Sequential or Parallel
    uint isLayoutAnchor : 1;  // if this anchor is an internal layout anchor
    uint isCenterAnchor : 1;
    uint orientation : 1;
    uint dependency : 2;      // either Independent, Master or Slave
};

#ifdef QT_DEBUG
inline QString AnchorData::toString() const
{
    return QString::fromAscii("Anchor(%1)").arg(name);
}
#endif

struct SequentialAnchorData : public AnchorData
{
    SequentialAnchorData(const QVector<AnchorVertex *> &vertices, const QVector<AnchorData *> &edges)
        : AnchorData(), m_children(vertices), m_edges(edges)
    {
        type = AnchorData::Sequential;
        orientation = m_edges.at(0)->orientation;
#ifdef QT_DEBUG
        name = QString::fromAscii("%1 -- %2").arg(vertices.first()->toString(), vertices.last()->toString());
#endif
    }

    virtual void updateChildrenSizes();
    void calculateSizeHints();

    QVector<AnchorVertex*> m_children;          // list of vertices in the sequence
    QVector<AnchorData*> m_edges;               // keep the list of edges too.
};

struct ParallelAnchorData : public AnchorData
{
    ParallelAnchorData(AnchorData *first, AnchorData *second)
        : AnchorData(), firstEdge(first), secondEdge(second)
    {
        type = AnchorData::Parallel;
        orientation = first->orientation;

        // This assert whether the child anchors share their vertices
        Q_ASSERT(((first->from == second->from) && (first->to == second->to)) ||
                 ((first->from == second->to) && (first->to == second->from)));

        // Our convention will be that the parallel group anchor will have the same
        // direction as the first anchor.
        from = first->from;
        to = first->to;
#ifdef QT_DEBUG
        name = QString::fromAscii("%1 | %2").arg(first->toString(), second->toString());
#endif
    }

    virtual void updateChildrenSizes();
    bool calculateSizeHints();

    bool secondForward() const {
        // We have the convention that the first children will define the direction of the
        // pararell group. Note that we can't rely on 'this->from' or 'this->to'  because they
        // might be changed by vertex simplification.
        return firstEdge->from == secondEdge->from;
    }

    AnchorData* firstEdge;
    AnchorData* secondEdge;

    QList<QSimplexConstraint *> m_firstConstraints;
    QList<QSimplexConstraint *> m_secondConstraints;
};

struct AnchorVertexPair : public AnchorVertex {
    AnchorVertexPair(AnchorVertex *v1, AnchorVertex *v2, AnchorData *data)
        : AnchorVertex(), m_first(v1), m_second(v2), m_removedAnchor(data) {
        m_type = AnchorVertex::Pair;
    }

    AnchorVertex *m_first;
    AnchorVertex *m_second;

    AnchorData *m_removedAnchor;
    QList<AnchorData *> m_firstAnchors;
    QList<AnchorData *> m_secondAnchors;
};

#ifdef QT_DEBUG
inline QString AnchorVertex::toString() const
{
    if (!this) {
        return QLatin1String("NULL");
    } else if (m_type == Pair) {
        const AnchorVertexPair *vp = static_cast<const AnchorVertexPair *>(this);
        return QString::fromAscii("(%1, %2)").arg(vp->m_first->toString()).arg(vp->m_second->toString());
    } else if (!m_item) {
        return QString::fromAscii("NULL_%1").arg(quintptr(this));
    }
    QString edge;
    switch (m_edge) {
    case Qt::AnchorLeft:
        edge = QLatin1String("Left");
        break;
    case Qt::AnchorHorizontalCenter:
        edge = QLatin1String("HorizontalCenter");
        break;
    case Qt::AnchorRight:
        edge = QLatin1String("Right");
        break;
    case Qt::AnchorTop:
        edge = QLatin1String("Top");
        break;
    case Qt::AnchorVerticalCenter:
        edge = QLatin1String("VerticalCenter");
        break;
    case Qt::AnchorBottom:
        edge = QLatin1String("Bottom");
        break;
    default:
        edge = QLatin1String("None");
        break;
    }
    QString itemName;
    if (m_item->isLayout()) {
        itemName = QLatin1String("layout");
    } else {
        if (QGraphicsItem *item = m_item->graphicsItem()) {
            itemName = item->data(0).toString();
        }
    }
    edge.insert(0, QLatin1String("%1_"));
    return edge.arg(itemName);
}
#endif

class GraphPath
{
public:
    GraphPath() {}

    QSimplexConstraint *constraint(const GraphPath &path) const;
#ifdef QT_DEBUG
    QString toString() const;
#endif
    QSet<AnchorData *> positives;
    QSet<AnchorData *> negatives;
};

class QGraphicsAnchorLayoutPrivate;
class QGraphicsAnchorPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QGraphicsAnchor)

public:
    explicit QGraphicsAnchorPrivate(int version = QObjectPrivateVersion);
    ~QGraphicsAnchorPrivate();

    void setSpacing(qreal value);
    void unsetSpacing();
    qreal spacing() const;

    void setSizePolicy(QSizePolicy::Policy policy);

    QGraphicsAnchorLayoutPrivate *layoutPrivate;
    AnchorData *data;

    // Size information for user controlled anchor
    QSizePolicy::Policy sizePolicy;
    qreal preferredSize;

    uint hasSize : 1;         // if false, get size from style.
};




class Q_AUTOTEST_EXPORT QGraphicsAnchorLayoutPrivate : public QGraphicsLayoutPrivate
{
    Q_DECLARE_PUBLIC(QGraphicsAnchorLayout)

public:
    // When the layout geometry is different from its Minimum, Preferred
    // or Maximum values, interpolation is used to calculate the geometries
    // of the items.
    //
    // Interval represents which interpolation interval are we operating in.
    enum Interval {
        MinimumToMinPreferred = 0,
        MinPreferredToPreferred,
        PreferredToMaxPreferred,
        MaxPreferredToMaximum
    };

    // Several structures internal to the layout are duplicated to handle
    // both Horizontal and Vertical restrictions.
    //
    // Orientation is used to reference the right structure in each context
    enum Orientation {
        Horizontal = 0,
        Vertical,
        NOrientations
    };

    QGraphicsAnchorLayoutPrivate();

    static QGraphicsAnchorLayoutPrivate *get(QGraphicsAnchorLayout *q)
    {
        return q ? q->d_func() : 0;
    }

    static Qt::AnchorPoint oppositeEdge(
        Qt::AnchorPoint edge);

    static Orientation edgeOrientation(Qt::AnchorPoint edge);

    static Qt::AnchorPoint pickEdge(Qt::AnchorPoint edge, Orientation orientation)
    {
        if (orientation == Vertical && int(edge) <= 2)
            return (Qt::AnchorPoint)(edge + 3);
        else if (orientation == Horizontal && int(edge) >= 3) {
            return (Qt::AnchorPoint)(edge - 3);
        }
        return edge;
    }

    // Init methods
    void createLayoutEdges();
    void deleteLayoutEdges();
    void createItemEdges(QGraphicsLayoutItem *item);
    void createCenterAnchors(QGraphicsLayoutItem *item, Qt::AnchorPoint centerEdge);
    void removeCenterAnchors(QGraphicsLayoutItem *item, Qt::AnchorPoint centerEdge, bool substitute = true);
    void removeCenterConstraints(QGraphicsLayoutItem *item, Orientation orientation);

    QGraphicsAnchor *acquireGraphicsAnchor(AnchorData *data)
    {
        Q_Q(QGraphicsAnchorLayout);
        if (!data->graphicsAnchor) {
            data->graphicsAnchor = new QGraphicsAnchor(q);
            data->graphicsAnchor->d_func()->data = data;
        }
        return data->graphicsAnchor;
    }

    // function used by the 4 API functions
    QGraphicsAnchor *addAnchor(QGraphicsLayoutItem *firstItem,
                            Qt::AnchorPoint firstEdge,
                            QGraphicsLayoutItem *secondItem,
                            Qt::AnchorPoint secondEdge,
                            qreal *spacing = 0);

    // Helper for Anchor Manipulation methods
    void addAnchor_helper(QGraphicsLayoutItem *firstItem,
                   Qt::AnchorPoint firstEdge,
                   QGraphicsLayoutItem *secondItem,
                   Qt::AnchorPoint secondEdge,
                   AnchorData *data);

    QGraphicsAnchor *getAnchor(QGraphicsLayoutItem *firstItem, Qt::AnchorPoint firstEdge,
                               QGraphicsLayoutItem *secondItem, Qt::AnchorPoint secondEdge);

    void removeAnchor(AnchorVertex *firstVertex, AnchorVertex *secondVertex);
    void removeAnchor_helper(AnchorVertex *v1, AnchorVertex *v2);

    void removeAnchors(QGraphicsLayoutItem *item);

    void removeVertex(QGraphicsLayoutItem *item, Qt::AnchorPoint edge);

    void correctEdgeDirection(QGraphicsLayoutItem *&firstItem,
                              Qt::AnchorPoint &firstEdge,
                              QGraphicsLayoutItem *&secondItem,
                              Qt::AnchorPoint &secondEdge);

    QLayoutStyleInfo &styleInfo() const;

    AnchorData *addAnchorMaybeParallel(AnchorData *newAnchor, bool *feasible);

    // Activation
    void calculateGraphs();
    void calculateGraphs(Orientation orientation);

    // Simplification
    bool simplifyGraph(Orientation orientation);
    bool simplifyVertices(Orientation orientation);
    bool simplifyGraphIteration(Orientation orientation, bool *feasible);

    bool replaceVertex(Orientation orientation, AnchorVertex *oldV,
                       AnchorVertex *newV, const QList<AnchorData *> &edges);


    void restoreSimplifiedGraph(Orientation orientation);
    void restoreSimplifiedAnchor(AnchorData *edge);
    void restoreSimplifiedConstraints(ParallelAnchorData *parallel);
    void restoreVertices(Orientation orientation);

    bool calculateTrunk(Orientation orientation, const GraphPath &trunkPath,
                        const QList<QSimplexConstraint *> &constraints,
                        const QList<AnchorData *> &variables);
    bool calculateNonTrunk(const QList<QSimplexConstraint *> &constraints,
                           const QList<AnchorData *> &variables);

    // Support functions for calculateGraph()
    void refreshAllSizeHints(Orientation orientation);
    void findPaths(Orientation orientation);
    void constraintsFromPaths(Orientation orientation);
    void updateAnchorSizes(Orientation orientation);
    QList<QSimplexConstraint *> constraintsFromSizeHints(const QList<AnchorData *> &anchors);
    QList<QList<QSimplexConstraint *> > getGraphParts(Orientation orientation);
    void identifyFloatItems(const QSet<AnchorData *> &visited, Orientation orientation);
    void identifyNonFloatItems_helper(const AnchorData *ad, QSet<QGraphicsLayoutItem *> *nonFloatingItemsIdentifiedSoFar);

    inline AnchorVertex *internalVertex(const QPair<QGraphicsLayoutItem*, Qt::AnchorPoint> &itemEdge) const
    {
        return m_vertexList.value(itemEdge).first;
    }

    inline AnchorVertex *internalVertex(const QGraphicsLayoutItem *item, Qt::AnchorPoint edge) const
    {
        return internalVertex(qMakePair(const_cast<QGraphicsLayoutItem *>(item), edge));
    }

    inline void changeLayoutVertex(Orientation orientation, AnchorVertex *oldV, AnchorVertex *newV)
    {
        if (layoutFirstVertex[orientation] == oldV)
            layoutFirstVertex[orientation] = newV;
        else if (layoutCentralVertex[orientation] == oldV)
            layoutCentralVertex[orientation] = newV;
        else if (layoutLastVertex[orientation] == oldV)
            layoutLastVertex[orientation] = newV;
    }


    AnchorVertex *addInternalVertex(QGraphicsLayoutItem *item, Qt::AnchorPoint edge);
    void removeInternalVertex(QGraphicsLayoutItem *item, Qt::AnchorPoint edge);

    // Geometry interpolation methods
    void setItemsGeometries(const QRectF &geom);

    void calculateVertexPositions(Orientation orientation);
    void setupEdgesInterpolation(Orientation orientation);
    void interpolateEdge(AnchorVertex *base, AnchorData *edge);

    // Linear Programming solver methods
    bool solveMinMax(const QList<QSimplexConstraint *> &constraints,
                     GraphPath path, qreal *min, qreal *max);
    bool solvePreferred(const QList<QSimplexConstraint *> &constraints,
                        const QList<AnchorData *> &variables);
    bool hasConflicts() const;

#ifdef QT_DEBUG
    void dumpGraph(const QString &name = QString());
#endif


    qreal spacings[NOrientations];
    // Size hints from simplex engine
    qreal sizeHints[2][3];

    // Items
    QVector<QGraphicsLayoutItem *> items;

    // Mapping between high level anchorage points (Item, Edge) to low level
    // ones (Graph Vertices)

    QHash<QPair<QGraphicsLayoutItem*, Qt::AnchorPoint>, QPair<AnchorVertex *, int> > m_vertexList;

    // Internal graph of anchorage points and anchors, for both orientations
    Graph<AnchorVertex, AnchorData> graph[2];

    AnchorVertex *layoutFirstVertex[2];
    AnchorVertex *layoutCentralVertex[2];
    AnchorVertex *layoutLastVertex[2];

    // Combined anchors in order of creation
    QList<AnchorVertexPair *> simplifiedVertices[2];
    QList<AnchorData *> anchorsFromSimplifiedVertices[2];

    // Graph paths and constraints, for both orientations
    QMultiHash<AnchorVertex *, GraphPath> graphPaths[2];
    QList<QSimplexConstraint *> constraints[2];
    QList<QSimplexConstraint *> itemCenterConstraints[2];

    // The interpolation interval and progress based on the current size
    // as well as the key values (minimum, preferred and maximum)
    Interval interpolationInterval[2];
    qreal interpolationProgress[2];

    bool graphHasConflicts[2];
    QSet<QGraphicsLayoutItem *> m_floatItems[2];

#if defined(QT_DEBUG) || defined(Q_AUTOTEST_EXPORT)
    bool lastCalculationUsedSimplex[2];
#endif

    uint calculateGraphCacheDirty : 1;
    mutable uint styleInfoDirty : 1;
    mutable QLayoutStyleInfo cachedStyleInfo;

    friend class QGraphicsAnchorPrivate;
};

QT_END_NAMESPACE
#endif //QT_NO_GRAPHICSVIEW

#endif