path: root/src/declarative/graphicsitems/qdeclarativepathview.cpp

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#include "qdeclarativepathview_p.h"
#include "qdeclarativepathview_p_p.h"

#include <qdeclarativestate_p.h>
#include <qdeclarativeopenmetaobject_p.h>

#include <QDebug>
#include <QEvent>
#include <qlistmodelinterface_p.h>
#include <QGraphicsSceneEvent>

#include <math.h>

QT_BEGIN_NAMESPACE

inline qreal qmlMod(qreal x, qreal y)
{
#ifdef QT_USE_MATH_H_FLOATS
    if(sizeof(qreal) == sizeof(float))
        return fmodf(float(x), float(y));
    else
#endif
        return fmod(x, y);
}


class QDeclarativePathViewAttached : public QObject
{
    Q_OBJECT

    Q_PROPERTY(bool onPath READ isOnPath NOTIFY onPathChanged)
public:
    QDeclarativePathViewAttached(QObject *parent)
    : QObject(parent), mo(new QDeclarativeOpenMetaObject(this)), onPath(false)
    {
    }

    ~QDeclarativePathViewAttached()
    {
        QDeclarativePathView::attachedProperties.remove(parent());
    }

    QVariant value(const QByteArray &name) const
    {
        return mo->value(name);
    }
    void setValue(const QByteArray &name, const QVariant &val)
    {
        mo->setValue(name, val);
    }

    bool isOnPath() const { return onPath; }
    void setOnPath(bool on) {
        if (on != onPath) {
            onPath = on;
            emit onPathChanged();
        }
    }

Q_SIGNALS:
    void onPathChanged();

private:
    QDeclarativeOpenMetaObject *mo;
    bool onPath;
};


QDeclarativeItem *QDeclarativePathViewPrivate::getItem(int modelIndex)
{
    Q_Q(QDeclarativePathView);
    requestedIndex = modelIndex;
    QDeclarativeItem *item = model->item(modelIndex, false);
    if (item) {
        if (QObject *obj = QDeclarativePathView::qmlAttachedProperties(item))
            static_cast<QDeclarativePathViewAttached *>(obj)->setOnPath(true);
        item->setParentItem(q);
    }
    requestedIndex = -1;
    return item;
}

void QDeclarativePathViewPrivate::releaseItem(QDeclarativeItem *item)
{
    if (!item || !model)
        return;
    if (QObject *obj = QDeclarativePathView::qmlAttachedProperties(item))
        static_cast<QDeclarativePathViewAttached *>(obj)->setOnPath(false);
    if (model->release(item) == 0) {
        if (QObject *obj = QDeclarativePathView::qmlAttachedProperties(item))
            static_cast<QDeclarativePathViewAttached *>(obj)->setOnPath(false);
    }
}

/*!
    \qmlclass PathView QDeclarativePathView
    \since 4.7
    \brief The PathView element lays out model-provided items on a path.
    \inherits Item

    The model is typically provided by a QAbstractListModel "C++ model object", but can also be created directly in QML.

    The items are laid out along a path defined by a \l Path and may be flicked to scroll.

    \snippet doc/src/snippets/declarative/pathview/pathview.qml 0

    \image pathview.gif

    \sa Path
*/

QDeclarativePathView::QDeclarativePathView(QDeclarativeItem *parent)
  : QDeclarativeItem(*(new QDeclarativePathViewPrivate), parent)
{
    Q_D(QDeclarativePathView);
    d->init();
}

QDeclarativePathView::~QDeclarativePathView()
{
    Q_D(QDeclarativePathView);
    if (d->ownModel)
        delete d->model;
}

/*!
    \qmlattachedproperty bool PathView::onPath
    This attached property holds whether the item is currently on the path.

    If a pathItemCount has been set, it is possible that some items may
    be instantiated, but not considered to be currently on the path.
    Usually, these items would be set invisible, for example:

    \code
    Component {
        Rectangle {
            visible: PathView.onPath
            ...
        }
    }
    \endcode

    It is attached to each instance of the delegate.
*/

/*!
    \qmlproperty model PathView::model
    This property holds the model providing data for the view.

    The model provides a set of data that is used to create the items for the view.
    For large or dynamic datasets the model is usually provided by a C++ model object.
    Models can also be created directly in XML, using the ListModel element.

    \sa {qmlmodels}{Data Models}
*/
QVariant QDeclarativePathView::model() const
{
    Q_D(const QDeclarativePathView);
    return d->modelVariant;
}

void QDeclarativePathView::setModel(const QVariant &model)
{
    Q_D(QDeclarativePathView);
    if (d->modelVariant == model)
        return;

    if (d->model) {
        disconnect(d->model, SIGNAL(itemsInserted(int,int)), this, SLOT(itemsInserted(int,int)));
        disconnect(d->model, SIGNAL(itemsRemoved(int,int)), this, SLOT(itemsRemoved(int,int)));
        disconnect(d->model, SIGNAL(modelReset()), this, SLOT(modelReset()));
        disconnect(d->model, SIGNAL(createdItem(int, QDeclarativeItem*)), this, SLOT(createdItem(int,QDeclarativeItem*)));
        for (int i=0; i<d->items.count(); i++){
            QDeclarativeItem *p = d->items[i];
            d->model->release(p);
        }
        d->items.clear();
    }

    d->modelVariant = model;
    QObject *object = qvariant_cast<QObject*>(model);
    QDeclarativeVisualModel *vim = 0;
    if (object && (vim = qobject_cast<QDeclarativeVisualModel *>(object))) {
        if (d->ownModel) {
            delete d->model;
            d->ownModel = false;
        }
        d->model = vim;
    } else {
        if (!d->ownModel) {
            d->model = new QDeclarativeVisualDataModel(qmlContext(this));
            d->ownModel = true;
        }
        if (QDeclarativeVisualDataModel *dataModel = qobject_cast<QDeclarativeVisualDataModel*>(d->model))
            dataModel->setModel(model);
    }
    if (d->model) {
        connect(d->model, SIGNAL(itemsInserted(int,int)), this, SLOT(itemsInserted(int,int)));
        connect(d->model, SIGNAL(itemsRemoved(int,int)), this, SLOT(itemsRemoved(int,int)));
        connect(d->model, SIGNAL(modelReset()), this, SLOT(modelReset()));
        connect(d->model, SIGNAL(createdItem(int, QDeclarativeItem*)), this, SLOT(createdItem(int,QDeclarativeItem*)));
    }
    d->firstIndex = 0;
    d->pathOffset = 0;
    d->regenerate();
    d->fixOffset();
    emit modelChanged();
}

/*!
    \qmlproperty int PathView::count
    This property holds the number of items in the model.
*/
int QDeclarativePathView::count() const
{
    Q_D(const QDeclarativePathView);
    return d->model ? d->model->count() : 0;
}

/*!
    \qmlproperty Path PathView::path
    \default
    This property holds the path used to lay out the items.
    For more information see the \l Path documentation.
*/
QDeclarativePath *QDeclarativePathView::path() const
{
    Q_D(const QDeclarativePathView);
    return d->path;
}

void QDeclarativePathView::setPath(QDeclarativePath *path)
{
    Q_D(QDeclarativePathView);
    if (d->path == path)
        return;
    d->path = path;
    connect(d->path, SIGNAL(changed()), this, SLOT(refill()));
    d->regenerate();
    emit pathChanged();
}

/*!
    \qmlproperty int PathView::currentIndex
    This property holds the index of the current item.
*/
int QDeclarativePathView::currentIndex() const
{
    Q_D(const QDeclarativePathView);
    return d->currentIndex;
}

void QDeclarativePathView::setCurrentIndex(int idx)
{
    Q_D(QDeclarativePathView);
    if (d->model && d->model->count())
        idx = qAbs(idx % d->model->count());
    if (d->model && idx != d->currentIndex) {
        d->currentIndex = idx;
        if (d->model->count()) {
            d->snapToCurrent();
            int itemIndex = (idx - d->firstIndex + d->model->count()) % d->model->count();
            if (itemIndex < d->items.count())
                d->items.at(itemIndex)->setFocus(true);
        }
        emit currentIndexChanged();
    }
}

/*!
    \qmlproperty real PathView::offset

    The offset specifies how far along the path the items are from their initial positions.
*/
qreal QDeclarativePathView::offset() const
{
    Q_D(const QDeclarativePathView);
    return d->_offset;
}

void QDeclarativePathView::setOffset(qreal offset)
{
    Q_D(QDeclarativePathView);
    d->setOffset(offset);
    d->updateCurrent();
}

void QDeclarativePathViewPrivate::setOffset(qreal o)
{
    Q_Q(QDeclarativePathView);
    if (_offset != o) {
        _offset = qmlMod(o, qreal(100.0));
        if (_offset < 0)
            _offset = 100.0 + _offset;
        q->refill();
    }
}

/*!
    \qmlproperty real PathView::snapPosition

    This property determines the position (0.0-1.0) the nearest item will snap to.
*/
qreal QDeclarativePathView::snapPosition() const
{
    Q_D(const QDeclarativePathView);
    return d->snapPos;
}

void QDeclarativePathView::setSnapPosition(qreal pos)
{
    Q_D(QDeclarativePathView);
    qreal normalizedPos = pos - int(pos);
    if (qFuzzyCompare(normalizedPos, d->snapPos))
        return;
    d->snapPos = normalizedPos;
    d->fixOffset();
    emit snapPositionChanged();
}

/*!
    \qmlproperty real PathView::dragMargin
    This property holds the maximum distance from the path that initiate mouse dragging.

    By default the path can only be dragged by clicking on an item.  If
    dragMargin is greater than zero, a drag can be initiated by clicking
    within dragMargin pixels of the path.
*/
qreal QDeclarativePathView::dragMargin() const
{
    Q_D(const QDeclarativePathView);
    return d->dragMargin;
}

void QDeclarativePathView::setDragMargin(qreal dragMargin)
{
    Q_D(QDeclarativePathView);
    if (d->dragMargin == dragMargin)
        return;
    d->dragMargin = dragMargin;
    emit dragMarginChanged();
}

/*!
    \qmlproperty component PathView::delegate

    The delegate provides a template defining each item instantiated by the view.
    The index is exposed as an accessible \c index property.  Properties of the
    model are also available depending upon the type of \l {qmlmodels}{Data Model}.

    Note that the PathView will layout the items based on the size of the root
    item in the delegate.

    Here is an example delegate:
    \snippet doc/src/snippets/declarative/pathview/pathview.qml 1
*/
QDeclarativeComponent *QDeclarativePathView::delegate() const
{
    Q_D(const QDeclarativePathView);
     if (d->model) {
        if (QDeclarativeVisualDataModel *dataModel = qobject_cast<QDeclarativeVisualDataModel*>(d->model))
            return dataModel->delegate();
    }

    return 0;
}

void QDeclarativePathView::setDelegate(QDeclarativeComponent *delegate)
{
    Q_D(QDeclarativePathView);
    if (delegate == this->delegate())
        return;
    if (!d->ownModel) {
        d->model = new QDeclarativeVisualDataModel(qmlContext(this));
        d->ownModel = true;
    }
    if (QDeclarativeVisualDataModel *dataModel = qobject_cast<QDeclarativeVisualDataModel*>(d->model)) {
        dataModel->setDelegate(delegate);
        d->regenerate();
        emit delegateChanged();
    }
}

/*!
  \qmlproperty int PathView::pathItemCount
  This property holds the number of items visible on the path at any one time
*/
int QDeclarativePathView::pathItemCount() const
{
    Q_D(const QDeclarativePathView);
    return d->pathItems;
}

void QDeclarativePathView::setPathItemCount(int i)
{
    Q_D(QDeclarativePathView);
    if (i == d->pathItems)
        return;
    d->pathItems = i;
    d->regenerate();
    pathItemCountChanged();
}

QPointF QDeclarativePathViewPrivate::pointNear(const QPointF &point, qreal *nearPercent) const
{
    //XXX maybe do recursively at increasing resolution.
    qreal mindist = 1e10; // big number
    QPointF nearPoint = path->pointAt(0);
    qreal nearPc = 0;
    for (qreal i=1; i < 1000; i++) {
        QPointF pt = path->pointAt(i/1000.0);
        QPointF diff = pt - point;
        qreal dist = diff.x()*diff.x() + diff.y()*diff.y();
        if (dist < mindist) {
            nearPoint = pt;
            nearPc = i;
            mindist = dist;
        }
    }

    if (nearPercent)
        *nearPercent = nearPc / 10.0;

    return nearPoint;
}


void QDeclarativePathView::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    Q_D(QDeclarativePathView);
    if (!d->items.count())
        return;
    QPointF scenePoint = mapToScene(event->pos());
    int idx = 0;
    for (; idx < d->items.count(); ++idx) {
        QRectF rect = d->items.at(idx)->boundingRect();
        rect = d->items.at(idx)->mapToScene(rect).boundingRect();
        if (rect.contains(scenePoint))
            break;
    }
    if (idx == d->items.count() && d->dragMargin == 0.)  // didn't click on an item
        return;

    d->startPoint = d->pointNear(event->pos(), &d->startPc);
    if (idx == d->items.count()) {
        qreal distance = qAbs(event->pos().x() - d->startPoint.x()) + qAbs(event->pos().y() - d->startPoint.y());
        if (distance > d->dragMargin)
            return;
    }

    d->stealMouse = false;
    d->lastElapsed = 0;
    d->lastDist = 0;
    QDeclarativeItemPrivate::start(d->lastPosTime);
    d->tl.clear();
}

void QDeclarativePathView::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    Q_D(QDeclarativePathView);
    if (d->lastPosTime.isNull())
        return;

    if (!d->stealMouse) {
        QPointF delta = event->pos() - d->startPoint;
        if (qAbs(delta.x()) > QApplication::startDragDistance() && qAbs(delta.y()) > QApplication::startDragDistance())
            d->stealMouse = true;
    }

    if (d->stealMouse) {
        d->moveReason = QDeclarativePathViewPrivate::Mouse;
        qreal newPc;
        d->pointNear(event->pos(), &newPc);
        qreal diff = newPc - d->startPc;
        if (diff) {
            setOffset(d->_offset + diff);

            if (diff > 50)
                diff -= 100;
            else if (diff < -50)
                diff += 100;

            d->lastElapsed = QDeclarativeItemPrivate::restart(d->lastPosTime);
            d->lastDist = diff;
            d->startPc = newPc;
        }
    }
}

void QDeclarativePathView::mouseReleaseEvent(QGraphicsSceneMouseEvent *)
{
    Q_D(QDeclarativePathView);
    if (d->lastPosTime.isNull())
        return;

    qreal elapsed = qreal(d->lastElapsed + QDeclarativeItemPrivate::elapsed(d->lastPosTime)) / 1000.;
    qreal velocity = elapsed > 0. ? d->lastDist / elapsed : 0;
    if (d->model && d->model->count() && qAbs(velocity) > 5) {
        if (velocity > 100)
            velocity = 100;
        else if (velocity < -100)
            velocity = -100;
        qreal inc = qmlMod(d->_offset - d->snapPos, qreal(100.0 / d->model->count()));
        qreal dist = qAbs(velocity/2 - qmlMod(velocity/2, qreal(100.0 / d->model->count()) - inc));
        d->moveOffset.setValue(d->_offset);
        d->tl.accel(d->moveOffset, velocity, 10, dist);
        d->tl.callback(QDeclarativeTimeLineCallback(&d->moveOffset, d->fixOffsetCallback, d));
    } else {
        d->fixOffset();
    }

    d->lastPosTime = QTime();
    d->stealMouse = false;
    ungrabMouse();
}

bool QDeclarativePathView::sendMouseEvent(QGraphicsSceneMouseEvent *event)
{
    Q_D(QDeclarativePathView);
    QGraphicsSceneMouseEvent mouseEvent(event->type());
    QRectF myRect = mapToScene(QRectF(0, 0, width(), height())).boundingRect();
    QGraphicsScene *s = scene();
    QDeclarativeItem *grabber = s ? qobject_cast<QDeclarativeItem*>(s->mouseGrabberItem()) : 0;
    if ((d->stealMouse || myRect.contains(event->scenePos().toPoint())) && (!grabber || !grabber->keepMouseGrab())) {
        mouseEvent.setAccepted(false);
        for (int i = 0x1; i <= 0x10; i <<= 1) {
            if (event->buttons() & i) {
                Qt::MouseButton button = Qt::MouseButton(i);
                mouseEvent.setButtonDownPos(button, mapFromScene(event->buttonDownPos(button)));
            }
        }
        mouseEvent.setScenePos(event->scenePos());
        mouseEvent.setLastScenePos(event->lastScenePos());
        mouseEvent.setPos(mapFromScene(event->scenePos()));
        mouseEvent.setLastPos(mapFromScene(event->lastScenePos()));

        switch(mouseEvent.type()) {
        case QEvent::GraphicsSceneMouseMove:
            mouseMoveEvent(&mouseEvent);
            break;
        case QEvent::GraphicsSceneMousePress:
            mousePressEvent(&mouseEvent);
            break;
        case QEvent::GraphicsSceneMouseRelease:
            mouseReleaseEvent(&mouseEvent);
            break;
        default:
            break;
        }
        grabber = qobject_cast<QDeclarativeItem*>(s->mouseGrabberItem());
        if (grabber && d->stealMouse && !grabber->keepMouseGrab() && grabber != this)
            grabMouse();

        return d->stealMouse;
    } else if (!d->lastPosTime.isNull()) {
        d->lastPosTime = QTime();
    }
    return false;
}

bool QDeclarativePathView::sceneEventFilter(QGraphicsItem *i, QEvent *e)
{
    if (!isVisible())
        return QDeclarativeItem::sceneEventFilter(i, e);

    switch (e->type()) {
    case QEvent::GraphicsSceneMousePress:
    case QEvent::GraphicsSceneMouseMove:
    case QEvent::GraphicsSceneMouseRelease:
        {
            bool ret = sendMouseEvent(static_cast<QGraphicsSceneMouseEvent *>(e));
            if (e->type() == QEvent::GraphicsSceneMouseRelease)
                return ret;
            break;
        }
    default:
        break;
    }

    return QDeclarativeItem::sceneEventFilter(i, e);
}

void QDeclarativePathView::componentComplete()
{
    Q_D(QDeclarativePathView);
    QDeclarativeItem::componentComplete();
    d->regenerate();

    // move to correct offset
    if (d->items.count()) {
        int itemIndex = (d->currentIndex - d->firstIndex + d->model->count()) % d->model->count();

        itemIndex += d->pathOffset;
        itemIndex %= d->items.count();
        qreal targetOffset = qmlMod(100 + (d->snapPos*100) - 100.0 * itemIndex / d->items.count(), qreal(100.0));

        if (targetOffset < 0)
            targetOffset = 100.0 + targetOffset;
        if (targetOffset != d->_offset) {
            d->moveOffset.setValue(targetOffset);
        }
    }
}

void QDeclarativePathViewPrivate::regenerate()
{
    Q_Q(QDeclarativePathView);
    if (!q->isComponentComplete())
        return;

    for (int i=0; i<items.count(); i++){
        QDeclarativeItem *p = items[i];
        releaseItem(p);
    }
    items.clear();

    if (!isValid())
        return;

    if (firstIndex >= model->count())
        firstIndex = model->count()-1;
    if (pathOffset >= model->count())
        pathOffset = model->count()-1;

    int numItems = pathItems >= 0 ? pathItems : model->count();
    for (int i=0; i < numItems && i < model->count(); ++i){
        int index = (i + firstIndex) % model->count();
        QDeclarativeItem *item = getItem(index);
        if (!item) {
            qWarning() << "PathView: Cannot create item, index" << (i + firstIndex) % model->count();
            return;
        }
        items.append(item);
        item->setZValue(i);
        model->completeItem();
        if (currentIndex == index)
            item->setFocus(true);
    }
    q->refill();
}

void QDeclarativePathViewPrivate::updateItem(QDeclarativeItem *item, qreal percent)
{
    if (QObject *obj = QDeclarativePathView::qmlAttachedProperties(item)) {
        foreach(const QString &attr, path->attributes())
            static_cast<QDeclarativePathViewAttached *>(obj)->setValue(attr.toUtf8(), path->attributeAt(attr, percent));
    }
    QPointF pf = path->pointAt(percent);
    item->setX(pf.x() - item->width()*item->scale()/2);
    item->setY(pf.y() - item->height()*item->scale()/2);
}

void QDeclarativePathView::refill()
{
    Q_D(QDeclarativePathView);
    if (!d->isValid() || !isComponentComplete())
        return;

    QList<qreal> positions;
    for (int i=0; i<d->items.count(); i++){
        qreal percent = i * (100. / d->items.count());
        percent = percent + d->_offset;
        percent = qmlMod(percent, qreal(100.0));
        positions << qAbs(percent/100.0);
    }

    if (d->pathItems==-1) {
        for (int i=0; i<positions.count(); i++)
            d->updateItem(d->items.at(i), positions[i]);
        return;
    }

    QList<qreal> rotatedPositions;
    for (int i=0; i<d->items.count(); i++)
        rotatedPositions << positions[(i + d->pathOffset + d->items.count()) % d->items.count()];

    int wrapIndex= -1;
    for (int i=0; i<d->items.count()-1; i++) {
        if (rotatedPositions[i] > rotatedPositions[i+1]){
            wrapIndex = i;
            break;
        }
    }
    if (wrapIndex != -1 ){
        //A wraparound has occured
        if (wrapIndex < d->items.count()/2){
            while(wrapIndex-- >= 0){
                QDeclarativeItem* p = d->items.takeFirst();
                d->updateItem(p, 0.0);
                d->releaseItem(p);
                d->firstIndex++;
                d->firstIndex %= d->model->count();
                int index = (d->firstIndex + d->items.count())%d->model->count();
                QDeclarativeItem *item = d->getItem(index);
                item->setZValue(wrapIndex);
                d->model->completeItem();
                if (d->currentIndex == index)
                    item->setFocus(true);
                d->items << item;
                d->pathOffset++;
                d->pathOffset=d->pathOffset % d->items.count();
            }
        } else {
            while(wrapIndex++ < d->items.count()-1){
                QDeclarativeItem* p = d->items.takeLast();
                d->updateItem(p, 1.0);
                d->releaseItem(p);
                d->firstIndex--;
                if (d->firstIndex < 0)
                    d->firstIndex = d->model->count() - 1;
                QDeclarativeItem *item = d->getItem(d->firstIndex);
                item->setZValue(d->firstIndex);
                d->model->completeItem();
                if (d->currentIndex == d->firstIndex)
                    item->setFocus(true);
                d->items.prepend(item);
                d->pathOffset--;
                if (d->pathOffset < 0)
                    d->pathOffset = d->items.count() - 1;
            }
        }
        for (int i=0; i<d->items.count(); i++)
            rotatedPositions[i] = positions[(i + d->pathOffset + d->items.count())
                                    % d->items.count()];
    }
    for (int i=0; i<d->items.count(); i++)
        d->updateItem(d->items.at(i), rotatedPositions[i]);
}

void QDeclarativePathView::itemsInserted(int modelIndex, int count)
{
    //XXX support animated insertion
    Q_D(QDeclarativePathView);
    if (!d->isValid() || !isComponentComplete())
        return;
    if (d->pathItems == -1) {
        for (int i = 0; i < count; ++i) {
            QDeclarativeItem *item = d->getItem(modelIndex + i);
            item->setZValue(modelIndex + i);
            d->model->completeItem();
            d->items.insert(modelIndex + i, item);
        }
        refill();
    } else {
        //XXX This is pretty heavy handed until we reference count items.
        d->regenerate();
    }

    // make sure the current item is still at the snap position
    int itemIndex = (d->currentIndex - d->firstIndex + d->model->count())%d->model->count();
    itemIndex += d->pathOffset;
    itemIndex %= d->items.count();
    qreal targetOffset = qmlMod(100 + (d->snapPos*100) - 100.0 * itemIndex / d->items.count(), qreal(100.0));

    if (targetOffset < 0)
        targetOffset = 100.0 + targetOffset;
    if (targetOffset != d->_offset)
        d->moveOffset.setValue(targetOffset);
}

void QDeclarativePathView::itemsRemoved(int modelIndex, int count)
{
    //XXX support animated removal
    Q_D(QDeclarativePathView);
    if (!d->isValid() || !isComponentComplete())
        return;
    if (d->pathItems == -1) {
        for (int i = 0; i < count && d->items.count() > modelIndex; ++i) {
            QDeclarativeItem* p = d->items.takeAt(modelIndex);
            d->model->release(p);
        }
        d->snapToCurrent();
        refill();
    } else {
        d->regenerate();
    }

    if (d->model->count() == 0) {
        d->currentIndex = -1;
        d->moveOffset.setValue(0);
        return;
    }

    // make sure the current item is still at the snap position
    if (d->currentIndex >= d->model->count())
        d->currentIndex = d->model->count() - 1;
    int itemIndex = (d->currentIndex - d->firstIndex + d->model->count())%d->model->count();
    itemIndex += d->pathOffset;
    itemIndex %= d->items.count();
    qreal targetOffset = qmlMod(100 + (d->snapPos*100) - 100.0 * itemIndex / d->items.count(), qreal(100.0));

    if (targetOffset < 0)
        targetOffset = 100.0 + targetOffset;
    if (targetOffset != d->_offset)
        d->moveOffset.setValue(targetOffset);
}

void QDeclarativePathView::modelReset()
{
    Q_D(QDeclarativePathView);
    d->regenerate();
}

void QDeclarativePathView::createdItem(int index, QDeclarativeItem *item)
{
    Q_D(QDeclarativePathView);
    if (d->requestedIndex != index) {
        item->setParentItem(this);
        d->updateItem(item, index < d->firstIndex ? 0.0 : 1.0);
    }
}

void QDeclarativePathView::destroyingItem(QDeclarativeItem *item)
{
    Q_UNUSED(item);
}

void QDeclarativePathView::ticked()
{
    Q_D(QDeclarativePathView);
    d->updateCurrent();
}

// find the item closest to the snap position
int QDeclarativePathViewPrivate::calcCurrentIndex()
{
    int current = -1;
    if (model && items.count()) {
        _offset = qmlMod(_offset, qreal(100.0));
        if (_offset < 0)
            _offset += 100.0;

        if (pathItems == -1) {
            qreal delta = qmlMod(_offset - snapPos, qreal(100.0));
            if (delta < 0)
                delta = 100.0 + delta;
            int ii = model->count() - qRound(delta * model->count() / 100);
            if (ii < 0)
                ii = 0;
            current = ii;
        } else {
            qreal bestDiff=1e9;
            int bestI=-1;
            for (int i=0; i<items.count(); i++){
                qreal percent = i * (100. / items.count());
                percent = percent + _offset;
                percent = qmlMod(percent, qreal(100.0));
                qreal diff = qAbs(snapPos - (percent/100.0));
                if (diff < bestDiff){
                    bestDiff = diff;
                    bestI = i;
                }
            }
            int modelIndex = (bestI - pathOffset + items.count())%items.count();
            modelIndex += firstIndex;
            current = modelIndex;
        }
        current = qAbs(current % model->count());
    }

    return current;
}

void QDeclarativePathViewPrivate::updateCurrent()
{
    Q_Q(QDeclarativePathView);
    if (moveReason != Mouse)
        return;
    int idx = calcCurrentIndex();
    if (model && idx != currentIndex) {
        currentIndex = idx;
        int itemIndex = (idx - firstIndex + model->count()) % model->count();
        if (itemIndex < items.count())
            items.at(itemIndex)->setFocus(true);
        emit q->currentIndexChanged();
    }
}

void QDeclarativePathViewPrivate::fixOffsetCallback(void *d)
{
    ((QDeclarativePathViewPrivate *)d)->fixOffset();
}

void QDeclarativePathViewPrivate::fixOffset()
{
    Q_Q(QDeclarativePathView);
    if (model && items.count()) {
        int curr = calcCurrentIndex();
        if (curr != currentIndex)
            q->setCurrentIndex(curr);
        else
            snapToCurrent();
    }
}

void QDeclarativePathViewPrivate::snapToCurrent()
{
    if (!model || model->count() <= 0)
        return;

    int itemIndex = (currentIndex - firstIndex + model->count()) % model->count();

    //Rounds is the number of times round to make the current item visible
    int rounds = itemIndex / items.count();
    int otherWayRounds = (model->count() - (itemIndex)) / items.count();
    if (otherWayRounds < rounds)
        rounds = -otherWayRounds;

    itemIndex += pathOffset;
    if(model->count() % items.count() && itemIndex - model->count() + items.count() > 0){
        //When model.count() is not a multiple of pathItemCount we need to manually
        //fix the index so that going backwards one step works correctly.
        itemIndex = itemIndex - model->count() + items.count();
    }
    itemIndex %= items.count();
    qreal targetOffset = qmlMod(100 + (snapPos*100) - 100.0 * itemIndex / items.count(), qreal(100.0));

    if (targetOffset < 0)
        targetOffset = 100.0 + targetOffset;
    if (targetOffset == _offset && rounds == 0)
        return;

    moveReason = Other;
    tl.clear();
    moveOffset.setValue(_offset);

    if (rounds!=0){
        //Compensate if the targetOffset would bring the target in from off the screen
        qreal distance = targetOffset - _offset;
        if (distance <= -50)
            rounds--;
        if (distance > 50)
            rounds++;
        tl.move(moveOffset, targetOffset + 100.0*(-rounds), QEasingCurve(QEasingCurve::InOutQuad),
                int(100*items.count()*qMax((qreal)(2.0/items.count()),(qreal)qAbs(rounds))));
        tl.callback(QDeclarativeTimeLineCallback(&moveOffset, fixOffsetCallback, this));
        return;
    }

    if (targetOffset - _offset > 50.0) {
        qreal distance = 100 - targetOffset + _offset;
        tl.move(moveOffset, 0.0, QEasingCurve(QEasingCurve::OutQuad), int(200 * _offset / distance));
        tl.set(moveOffset, 100.0);
        tl.move(moveOffset, targetOffset, QEasingCurve(QEasingCurve::InQuad), int(200 * (100-targetOffset) / distance));
    } else if (targetOffset - _offset <= -50.0) {
        qreal distance = 100 - _offset + targetOffset;
        tl.move(moveOffset, 100.0, QEasingCurve(QEasingCurve::OutQuad), int(200 * (100-_offset) / distance));
        tl.set(moveOffset, 0.0);
        tl.move(moveOffset, targetOffset, QEasingCurve(QEasingCurve::InQuad), int(200 * targetOffset / distance));
    } else {
        tl.move(moveOffset, targetOffset, QEasingCurve(QEasingCurve::InOutQuad), 200);
    }
}

QHash<QObject*, QObject*> QDeclarativePathView::attachedProperties;
QObject *QDeclarativePathView::qmlAttachedProperties(QObject *obj)
{
    QObject *rv = attachedProperties.value(obj);
    if (!rv) {
        rv = new QDeclarativePathViewAttached(obj);
        attachedProperties.insert(obj, rv);
    }
    return rv;
}

QT_END_NAMESPACE

#include <qdeclarativepathview.moc>