qdeclarativepositioners.cpp

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#include "private/qdeclarativepositioners_p.h"
#include "private/qdeclarativepositioners_p_p.h"

#include <qdeclarative.h>
#include <qdeclarativestate_p.h>
#include <qdeclarativestategroup_p.h>
#include <qdeclarativestateoperations_p.h>
#include <qdeclarativeinfo.h>
#include <QtCore/qmath.h>

#include <QDebug>
#include <QCoreApplication>

QT_BEGIN_NAMESPACE

static const QDeclarativeItemPrivate::ChangeTypes watchedChanges
    = QDeclarativeItemPrivate::Geometry
    | QDeclarativeItemPrivate::SiblingOrder
    | QDeclarativeItemPrivate::Visibility
    | QDeclarativeItemPrivate::Opacity
    | QDeclarativeItemPrivate::Destroyed;

void QDeclarativeBasePositionerPrivate::watchChanges(QGraphicsObject *other)
{
    if (QGraphicsItemPrivate::get(other)->isDeclarativeItem) {
        QDeclarativeItemPrivate *otherPrivate = static_cast<QDeclarativeItemPrivate*>(QGraphicsItemPrivate::get(other));
        otherPrivate->addItemChangeListener(this, watchedChanges);
    } else {
        Q_Q(QDeclarativeBasePositioner);
        QObject::connect(other, SIGNAL(widthChanged()), q, SLOT(graphicsWidgetGeometryChanged()));
        QObject::connect(other, SIGNAL(heightChanged()), q, SLOT(graphicsWidgetGeometryChanged()));
        QObject::connect(other, SIGNAL(opacityChanged()), q, SLOT(graphicsWidgetGeometryChanged()));
        QObject::connect(other, SIGNAL(visibleChanged()), q, SLOT(graphicsWidgetGeometryChanged()));
    }
}

void QDeclarativeBasePositionerPrivate::unwatchChanges(QGraphicsObject* other)
{
    if (QGraphicsItemPrivate::get(other)->isDeclarativeItem) {
        QDeclarativeItemPrivate *otherPrivate = static_cast<QDeclarativeItemPrivate*>(QGraphicsItemPrivate::get(other));
        otherPrivate->removeItemChangeListener(this, watchedChanges);
    } else {
        Q_Q(QDeclarativeBasePositioner);
        QObject::disconnect(other, SIGNAL(widthChanged()), q, SLOT(graphicsWidgetGeometryChanged()));
        QObject::disconnect(other, SIGNAL(heightChanged()), q, SLOT(graphicsWidgetGeometryChanged()));
        QObject::disconnect(other, SIGNAL(opacityChanged()), q, SLOT(graphicsWidgetGeometryChanged()));
        QObject::disconnect(other, SIGNAL(visibleChanged()), q, SLOT(graphicsWidgetGeometryChanged()));
    }
}

void QDeclarativeBasePositioner::graphicsWidgetGeometryChanged()
{
    prePositioning();
}

QDeclarativeBasePositioner::QDeclarativeBasePositioner(PositionerType at, QDeclarativeItem *parent)
    : QDeclarativeImplicitSizeItem(*(new QDeclarativeBasePositionerPrivate), parent)
{
    Q_D(QDeclarativeBasePositioner);
    d->init(at);
}

QDeclarativeBasePositioner::QDeclarativeBasePositioner(QDeclarativeBasePositionerPrivate &dd, PositionerType at, QDeclarativeItem *parent)
    : QDeclarativeImplicitSizeItem(dd, parent)
{
    Q_D(QDeclarativeBasePositioner);
    d->init(at);
}

QDeclarativeBasePositioner::~QDeclarativeBasePositioner()
{
    Q_D(QDeclarativeBasePositioner);
    for (int i = 0; i < positionedItems.count(); ++i)
        d->unwatchChanges(positionedItems.at(i).item);
    positionedItems.clear();
}

int QDeclarativeBasePositioner::spacing() const
{
    Q_D(const QDeclarativeBasePositioner);
    return d->spacing;
}

void QDeclarativeBasePositioner::setSpacing(int s)
{
    Q_D(QDeclarativeBasePositioner);
    if (s==d->spacing)
        return;
    d->spacing = s;
    prePositioning();
    emit spacingChanged();
}

QDeclarativeTransition *QDeclarativeBasePositioner::move() const
{
    Q_D(const QDeclarativeBasePositioner);
    return d->moveTransition;
}

void QDeclarativeBasePositioner::setMove(QDeclarativeTransition *mt)
{
    Q_D(QDeclarativeBasePositioner);
    if (mt == d->moveTransition)
        return;
    d->moveTransition = mt;
    emit moveChanged();
}

QDeclarativeTransition *QDeclarativeBasePositioner::add() const
{
    Q_D(const QDeclarativeBasePositioner);
    return d->addTransition;
}

void QDeclarativeBasePositioner::setAdd(QDeclarativeTransition *add)
{
    Q_D(QDeclarativeBasePositioner);
    if (add == d->addTransition)
        return;

    d->addTransition = add;
    emit addChanged();
}

void QDeclarativeBasePositioner::componentComplete()
{
    Q_D(QDeclarativeBasePositioner);
    QDeclarativeItem::componentComplete();
    positionedItems.reserve(d->QGraphicsItemPrivate::children.count());
    prePositioning();
    reportConflictingAnchors();
}

QVariant QDeclarativeBasePositioner::itemChange(GraphicsItemChange change,
                                       const QVariant &value)
{
    Q_D(QDeclarativeBasePositioner);
    if (change == ItemChildAddedChange){
        QGraphicsItem* item = value.value<QGraphicsItem*>();
        QGraphicsObject* child = 0;
        if(item)
            child = item->toGraphicsObject();
        if (child)
            prePositioning();
    } else if (change == ItemChildRemovedChange) {
        QGraphicsItem* item = value.value<QGraphicsItem*>();
        QGraphicsObject* child = 0;
        if(item)
            child = item->toGraphicsObject();
        if (child) {
            QDeclarativeBasePositioner::PositionedItem posItem(child);
            int idx = positionedItems.find(posItem);
            if (idx >= 0) {
                d->unwatchChanges(child);
                positionedItems.remove(idx);
            }
            prePositioning();
        }
    }
    return QDeclarativeItem::itemChange(change, value);
}

void QDeclarativeBasePositioner::prePositioning()
{
    Q_D(QDeclarativeBasePositioner);
    if (!isComponentComplete())
        return;

    if (d->doingPositioning)
        return;

    d->queuedPositioning = false;
    d->doingPositioning = true;
    //Need to order children by creation order modified by stacking order
    QList<QGraphicsItem *> children = d->QGraphicsItemPrivate::children;
    qSort(children.begin(), children.end(), d->insertionOrder);

    QPODVector<PositionedItem,8> oldItems;
    positionedItems.copyAndClear(oldItems);
    for (int ii = 0; ii < children.count(); ++ii) {
        QGraphicsObject *child = children.at(ii)->toGraphicsObject();
        if (!child)
            continue;
        QGraphicsItemPrivate *childPrivate = static_cast<QGraphicsItemPrivate*>(QGraphicsItemPrivate::get(child));
        PositionedItem *item = 0;
        PositionedItem posItem(child);
        int wIdx = oldItems.find(posItem);
        if (wIdx < 0) {
            d->watchChanges(child);
            positionedItems.append(posItem);
            item = &positionedItems[positionedItems.count()-1];
            item->isNew = true;
            if (child->opacity() <= 0.0 || childPrivate->explicitlyHidden || !childPrivate->width() || !childPrivate->height())
                item->isVisible = false;
        } else {
            item = &oldItems[wIdx];
            // Items are only omitted from positioning if they are explicitly hidden
            // i.e. their positioning is not affected if an ancestor is hidden.
            if (child->opacity() <= 0.0 || childPrivate->explicitlyHidden || !childPrivate->width() || !childPrivate->height()) {
                item->isVisible = false;
            } else if (!item->isVisible) {
                item->isVisible = true;
                item->isNew = true;
            } else {
                item->isNew = false;
            }
            positionedItems.append(*item);
        }
    }
    QSizeF contentSize;
    doPositioning(&contentSize);
    if(d->addTransition || d->moveTransition)
        finishApplyTransitions();
    d->doingPositioning = false;
    //Set implicit size to the size of its children
    setImplicitHeight(contentSize.height());
    setImplicitWidth(contentSize.width());
}

void QDeclarativeBasePositioner::positionX(int x, const PositionedItem &target)
{
    Q_D(QDeclarativeBasePositioner);
    if(d->type == Horizontal || d->type == Both){
        if (target.isNew) {
            if (!d->addTransition)
                target.item->setX(x);
            else
                d->addActions << QDeclarativeAction(target.item, QLatin1String("x"), QVariant(x));
        } else if (x != target.item->x()) {
            if (!d->moveTransition)
                target.item->setX(x);
            else
                d->moveActions << QDeclarativeAction(target.item, QLatin1String("x"), QVariant(x));
        }
    }
}

void QDeclarativeBasePositioner::positionY(int y, const PositionedItem &target)
{
    Q_D(QDeclarativeBasePositioner);
    if(d->type == Vertical || d->type == Both){
        if (target.isNew) {
            if (!d->addTransition)
                target.item->setY(y);
            else
                d->addActions << QDeclarativeAction(target.item, QLatin1String("y"), QVariant(y));
        } else if (y != target.item->y()) {
            if (!d->moveTransition)
                target.item->setY(y);
            else
                d->moveActions << QDeclarativeAction(target.item, QLatin1String("y"), QVariant(y));
        }
    }
}

void QDeclarativeBasePositioner::finishApplyTransitions()
{
    Q_D(QDeclarativeBasePositioner);
    // Note that if a transition is not set the transition manager will
    // apply the changes directly, in the case add/move aren't set
    d->addTransitionManager.transition(d->addActions, d->addTransition);
    d->moveTransitionManager.transition(d->moveActions, d->moveTransition);
    d->addActions.clear();
    d->moveActions.clear();
}

QDeclarativeColumn::QDeclarativeColumn(QDeclarativeItem *parent)
: QDeclarativeBasePositioner(Vertical, parent)
{
}

void QDeclarativeColumn::doPositioning(QSizeF *contentSize)
{
    int voffset = 0;

    for (int ii = 0; ii < positionedItems.count(); ++ii) {
        const PositionedItem &child = positionedItems.at(ii);
        if (!child.item || !child.isVisible)
            continue;

        if(child.item->y() != voffset)
            positionY(voffset, child);

        contentSize->setWidth(qMax(contentSize->width(), QGraphicsItemPrivate::get(child.item)->width()));

        voffset += QGraphicsItemPrivate::get(child.item)->height();
        voffset += spacing();
    }

    contentSize->setHeight(voffset - spacing());
}

void QDeclarativeColumn::reportConflictingAnchors()
{
    QDeclarativeBasePositionerPrivate *d = static_cast<QDeclarativeBasePositionerPrivate*>(QDeclarativeBasePositionerPrivate::get(this));
    for (int ii = 0; ii < positionedItems.count(); ++ii) {
        const PositionedItem &child = positionedItems.at(ii);
        if (child.item && QGraphicsItemPrivate::get(child.item)->isDeclarativeItem) {
            QDeclarativeAnchors *anchors = QDeclarativeItemPrivate::get(static_cast<QDeclarativeItem *>(child.item))->_anchors;
            if (anchors) {
                QDeclarativeAnchors::Anchors usedAnchors = anchors->usedAnchors();
                if (usedAnchors & QDeclarativeAnchors::TopAnchor ||
                    usedAnchors & QDeclarativeAnchors::BottomAnchor ||
                    usedAnchors & QDeclarativeAnchors::VCenterAnchor ||
                    anchors->fill() || anchors->centerIn()) {
                    d->anchorConflict = true;
                    break;
                }
            }
        }
    }
    if (d->anchorConflict) {
        qmlInfo(this) << "Cannot specify top, bottom, verticalCenter, fill or centerIn anchors for items inside Column";
    }
}

QDeclarativeRow::QDeclarativeRow(QDeclarativeItem *parent)
: QDeclarativeBasePositioner(Horizontal, parent)
{
}

Qt::LayoutDirection QDeclarativeRow::layoutDirection() const
{
    return QDeclarativeBasePositionerPrivate::getLayoutDirection(this);
}

void QDeclarativeRow::setLayoutDirection(Qt::LayoutDirection layoutDirection)
{
    QDeclarativeBasePositionerPrivate *d = static_cast<QDeclarativeBasePositionerPrivate* >(QDeclarativeBasePositionerPrivate::get(this));
    if (d->layoutDirection != layoutDirection) {
        d->layoutDirection = layoutDirection;
        // For RTL layout the positioning changes when the width changes.
        if (d->layoutDirection == Qt::RightToLeft)
            d->addItemChangeListener(d, QDeclarativeItemPrivate::Geometry);
        else
            d->removeItemChangeListener(d, QDeclarativeItemPrivate::Geometry);
        prePositioning();
        emit layoutDirectionChanged();
    }
}

Qt::LayoutDirection QDeclarativeRow::effectiveLayoutDirection() const
{
    return QDeclarativeBasePositionerPrivate::getEffectiveLayoutDirection(this);
}

void QDeclarativeRow::doPositioning(QSizeF *contentSize)
{
    QDeclarativeBasePositionerPrivate *d = static_cast<QDeclarativeBasePositionerPrivate*>(QDeclarativeBasePositionerPrivate::get(this));
    int hoffset = 0;

    QList<int> hoffsets;
    for (int ii = 0; ii < positionedItems.count(); ++ii) {
        const PositionedItem &child = positionedItems.at(ii);
        if (!child.item || !child.isVisible)
            continue;

        if(d->isLeftToRight()){
            if(child.item->x() != hoffset)
                positionX(hoffset, child);
        }else{
            hoffsets << hoffset;
        }

        contentSize->setHeight(qMax(contentSize->height(), QGraphicsItemPrivate::get(child.item)->height()));

        hoffset += QGraphicsItemPrivate::get(child.item)->width();
        hoffset += spacing();
    }

    contentSize->setWidth(hoffset - spacing());

    if(d->isLeftToRight())
        return;

    //Right to Left layout
    int end = 0;
    if(!widthValid())
        end = contentSize->width();
    else
        end = width();

    int acc = 0;
    for (int ii = 0; ii < positionedItems.count(); ++ii) {
        const PositionedItem &child = positionedItems.at(ii);
        if (!child.item || !child.isVisible)
            continue;
        hoffset = end - hoffsets[acc++] - QGraphicsItemPrivate::get(child.item)->width();
        if(child.item->x() != hoffset)
            positionX(hoffset, child);
    }
}

void QDeclarativeRow::reportConflictingAnchors()
{
    QDeclarativeBasePositionerPrivate *d = static_cast<QDeclarativeBasePositionerPrivate*>(QDeclarativeBasePositionerPrivate::get(this));
    for (int ii = 0; ii < positionedItems.count(); ++ii) {
        const PositionedItem &child = positionedItems.at(ii);
        if (child.item && QGraphicsItemPrivate::get(child.item)->isDeclarativeItem) {
            QDeclarativeAnchors *anchors = QDeclarativeItemPrivate::get(static_cast<QDeclarativeItem *>(child.item))->_anchors;
            if (anchors) {
                QDeclarativeAnchors::Anchors usedAnchors = anchors->usedAnchors();
                if (usedAnchors & QDeclarativeAnchors::LeftAnchor ||
                    usedAnchors & QDeclarativeAnchors::RightAnchor ||
                    usedAnchors & QDeclarativeAnchors::HCenterAnchor ||
                    anchors->fill() || anchors->centerIn()) {
                    d->anchorConflict = true;
                    break;
                }
            }
        }
    }
    if (d->anchorConflict)
        qmlInfo(this) << "Cannot specify left, right, horizontalCenter, fill or centerIn anchors for items inside Row";
}

QDeclarativeGrid::QDeclarativeGrid(QDeclarativeItem *parent) :
    QDeclarativeBasePositioner(Both, parent), m_rows(-1), m_columns(-1), m_flow(LeftToRight)
{
}

void QDeclarativeGrid::setColumns(const int columns)
{
    if (columns == m_columns)
        return;
    m_columns = columns;
    prePositioning();
    emit columnsChanged();
}

void QDeclarativeGrid::setRows(const int rows)
{
    if (rows == m_rows)
        return;
    m_rows = rows;
    prePositioning();
    emit rowsChanged();
}

QDeclarativeGrid::Flow QDeclarativeGrid::flow() const
{
    return m_flow;
}

void QDeclarativeGrid::setFlow(Flow flow)
{
    if (m_flow != flow) {
        m_flow = flow;
        prePositioning();
        emit flowChanged();
    }
}

Qt::LayoutDirection QDeclarativeGrid::layoutDirection() const
{
    return QDeclarativeBasePositionerPrivate::getLayoutDirection(this);
}

void QDeclarativeGrid::setLayoutDirection(Qt::LayoutDirection layoutDirection)
{
    QDeclarativeBasePositionerPrivate *d = static_cast<QDeclarativeBasePositionerPrivate*>(QDeclarativeBasePositionerPrivate::get(this));
    if (d->layoutDirection != layoutDirection) {
        d->layoutDirection = layoutDirection;
        // For RTL layout the positioning changes when the width changes.
        if (d->layoutDirection == Qt::RightToLeft)
            d->addItemChangeListener(d, QDeclarativeItemPrivate::Geometry);
        else
            d->removeItemChangeListener(d, QDeclarativeItemPrivate::Geometry);
        prePositioning();
        emit layoutDirectionChanged();;
    }
}

Qt::LayoutDirection QDeclarativeGrid::effectiveLayoutDirection() const
{
    return QDeclarativeBasePositionerPrivate::getEffectiveLayoutDirection(this);
}

void QDeclarativeGrid::doPositioning(QSizeF *contentSize)
{
    QDeclarativeBasePositionerPrivate *d = static_cast<QDeclarativeBasePositionerPrivate*>(QDeclarativeBasePositionerPrivate::get(this));
    int c = m_columns;
    int r = m_rows;
    //Is allocating the extra QPODVector too much overhead?
    QPODVector<PositionedItem, 8> visibleItems;//we aren't concerned with invisible items
    visibleItems.reserve(positionedItems.count());
    for(int i=0; i<positionedItems.count(); i++)
        if(positionedItems[i].item && positionedItems[i].isVisible)
            visibleItems.append(positionedItems[i]);

    int numVisible = visibleItems.count();
    if (m_columns <= 0 && m_rows <= 0){
        c = 4;
        r = (numVisible+3)/4;
    } else if (m_rows <= 0){
        r = (numVisible+(m_columns-1))/m_columns;
    } else if (m_columns <= 0){
        c = (numVisible+(m_rows-1))/m_rows;
    }

    if(r==0 || c==0)
        return; //Nothing to do

    QList<int> maxColWidth;
    QList<int> maxRowHeight;
    int childIndex =0;
    if (m_flow == LeftToRight) {
        for (int i=0; i < r; i++){
            for (int j=0; j < c; j++){
                if (j==0)
                    maxRowHeight << 0;
                if (i==0)
                    maxColWidth << 0;

                if (childIndex == visibleItems.count())
                    break;

                const PositionedItem &child = visibleItems.at(childIndex++);
                QGraphicsItemPrivate *childPrivate = QGraphicsItemPrivate::get(child.item);
                if (childPrivate->width() > maxColWidth[j])
                    maxColWidth[j] = childPrivate->width();
                if (childPrivate->height() > maxRowHeight[i])
                    maxRowHeight[i] = childPrivate->height();
            }
        }
    } else {
        for (int j=0; j < c; j++){
            for (int i=0; i < r; i++){
                if (j==0)
                    maxRowHeight << 0;
                if (i==0)
                    maxColWidth << 0;

                if (childIndex == visibleItems.count())
                    break;

                const PositionedItem &child = visibleItems.at(childIndex++);
                QGraphicsItemPrivate *childPrivate = QGraphicsItemPrivate::get(child.item);
                if (childPrivate->width() > maxColWidth[j])
                    maxColWidth[j] = childPrivate->width();
                if (childPrivate->height() > maxRowHeight[i])
                    maxRowHeight[i] = childPrivate->height();
            }
        }
    }

    int widthSum = 0;
    for(int j=0; j < maxColWidth.size(); j++){
        if(j)
            widthSum += spacing();
        widthSum += maxColWidth[j];
    }

    int heightSum = 0;
    for(int i=0; i < maxRowHeight.size(); i++){
        if(i)
            heightSum += spacing();
        heightSum += maxRowHeight[i];
    }

    contentSize->setHeight(heightSum);
    contentSize->setWidth(widthSum);

    int end = 0;
    if(widthValid())
        end = width();
    else
        end = widthSum;

    int xoffset=0;
    if(!d->isLeftToRight())
        xoffset=end;
    int yoffset=0;
    int curRow =0;
    int curCol =0;
    for (int i = 0; i < visibleItems.count(); ++i) {
        const PositionedItem &child = visibleItems.at(i);
        int childXOffset = xoffset;
        if(!d->isLeftToRight())
            childXOffset -= QGraphicsItemPrivate::get(child.item)->width();
        if((child.item->x()!=childXOffset)||(child.item->y()!=yoffset)){
            positionX(childXOffset, child);
            positionY(yoffset, child);
        }

        if (m_flow == LeftToRight) {
            if(d->isLeftToRight())
                xoffset+=maxColWidth[curCol]+spacing();
            else
                xoffset-=maxColWidth[curCol]+spacing();
            curCol++;
            curCol%=c;
            if (!curCol){
                yoffset+=maxRowHeight[curRow]+spacing();
                if(d->isLeftToRight())
                    xoffset=0;
                else
                    xoffset=end;
                curRow++;
                if (curRow>=r)
                    break;
            }
        } else {
            yoffset+=maxRowHeight[curRow]+spacing();
            curRow++;
            curRow%=r;
            if (!curRow){
                if(d->isLeftToRight())
                    xoffset+=maxColWidth[curCol]+spacing();
                else
                    xoffset-=maxColWidth[curCol]+spacing();
                yoffset=0;
                curCol++;
                if (curCol>=c)
                    break;
            }
        }
    }
}

void QDeclarativeGrid::reportConflictingAnchors()
{
    QDeclarativeBasePositionerPrivate *d = static_cast<QDeclarativeBasePositionerPrivate*>(QDeclarativeBasePositionerPrivate::get(this));
    for (int ii = 0; ii < positionedItems.count(); ++ii) {
        const PositionedItem &child = positionedItems.at(ii);
        if (child.item && QGraphicsItemPrivate::get(child.item)->isDeclarativeItem) {
            QDeclarativeAnchors *anchors = QDeclarativeItemPrivate::get(static_cast<QDeclarativeItem *>(child.item))->_anchors;
            if (anchors && (anchors->usedAnchors() || anchors->fill() || anchors->centerIn())) {
                d->anchorConflict = true;
                break;
            }
        }
    }
    if (d->anchorConflict)
        qmlInfo(this) << "Cannot specify anchors for items inside Grid";
}

class QDeclarativeFlowPrivate : public QDeclarativeBasePositionerPrivate
{
    Q_DECLARE_PUBLIC(QDeclarativeFlow)

public:
    QDeclarativeFlowPrivate()
        : QDeclarativeBasePositionerPrivate(), flow(QDeclarativeFlow::LeftToRight)
    {}

    QDeclarativeFlow::Flow flow;
};

QDeclarativeFlow::QDeclarativeFlow(QDeclarativeItem *parent)
: QDeclarativeBasePositioner(*(new QDeclarativeFlowPrivate), Both, parent)
{
    Q_D(QDeclarativeFlow);
    // Flow layout requires relayout if its own size changes too.
    d->addItemChangeListener(d, QDeclarativeItemPrivate::Geometry);
}

QDeclarativeFlow::Flow QDeclarativeFlow::flow() const
{
    Q_D(const QDeclarativeFlow);
    return d->flow;
}

void QDeclarativeFlow::setFlow(Flow flow)
{
    Q_D(QDeclarativeFlow);
    if (d->flow != flow) {
        d->flow = flow;
        prePositioning();
        emit flowChanged();
    }
}

Qt::LayoutDirection QDeclarativeFlow::layoutDirection() const
{
    Q_D(const QDeclarativeFlow);
    return d->layoutDirection;
}

void QDeclarativeFlow::setLayoutDirection(Qt::LayoutDirection layoutDirection)
{
    Q_D(QDeclarativeFlow);
    if (d->layoutDirection != layoutDirection) {
        d->layoutDirection = layoutDirection;
        prePositioning();
        emit layoutDirectionChanged();
    }
}

Qt::LayoutDirection QDeclarativeFlow::effectiveLayoutDirection() const
{
    return QDeclarativeBasePositionerPrivate::getEffectiveLayoutDirection(this);
}

void QDeclarativeFlow::doPositioning(QSizeF *contentSize)
{
    Q_D(QDeclarativeFlow);

    int hoffset = 0;
    int voffset = 0;
    int linemax = 0;
    QList<int> hoffsets;

    for (int i = 0; i < positionedItems.count(); ++i) {
        const PositionedItem &child = positionedItems.at(i);
        if (!child.item || !child.isVisible)
            continue;

        QGraphicsItemPrivate *childPrivate = QGraphicsItemPrivate::get(child.item);
        if (d->flow == LeftToRight)  {
            if (widthValid() && hoffset && hoffset + childPrivate->width() > width()) {
                hoffset = 0;
                voffset += linemax + spacing();
                linemax = 0;
            }
        } else {
            if (heightValid() && voffset && voffset + childPrivate->height() > height()) {
                voffset = 0;
                hoffset += linemax + spacing();
                linemax = 0;
            }
        }

        if(d->isLeftToRight()){
            if(child.item->x() != hoffset)
                positionX(hoffset, child);
        }else{
            hoffsets << hoffset;
        }
        if(child.item->y() != voffset)
            positionY(voffset, child);

        contentSize->setWidth(qMax(contentSize->width(), hoffset + childPrivate->width()));
        contentSize->setHeight(qMax(contentSize->height(), voffset + childPrivate->height()));

        if (d->flow == LeftToRight)  {
            hoffset += childPrivate->width();
            hoffset += spacing();
            linemax = qMax(linemax, qCeil(childPrivate->height()));
        } else {
            voffset += childPrivate->height();
            voffset += spacing();
            linemax = qMax(linemax, qCeil(childPrivate->width()));
        }
    }

    if(d->isLeftToRight())
        return;

    int end;
    if(widthValid())
        end = width();
    else
        end = contentSize->width();
    int acc = 0;
    for (int i = 0; i < positionedItems.count(); ++i) {
        const PositionedItem &child = positionedItems.at(i);
        if (!child.item || !child.isVisible)
            continue;
        hoffset = end - hoffsets[acc++] - QGraphicsItemPrivate::get(child.item)->width();
        if(child.item->x() != hoffset)
            positionX(hoffset, child);
    }
}

void QDeclarativeFlow::reportConflictingAnchors()
{
    Q_D(QDeclarativeFlow);
    for (int ii = 0; ii < positionedItems.count(); ++ii) {
        const PositionedItem &child = positionedItems.at(ii);
        if (child.item && QGraphicsItemPrivate::get(child.item)->isDeclarativeItem) {
            QDeclarativeAnchors *anchors = QDeclarativeItemPrivate::get(static_cast<QDeclarativeItem *>(child.item))->_anchors;
            if (anchors && (anchors->usedAnchors() || anchors->fill() || anchors->centerIn())) {
                d->anchorConflict = true;
                break;
            }
        }
    }
    if (d->anchorConflict)
        qmlInfo(this) << "Cannot specify anchors for items inside Flow";
}

QT_END_NAMESPACE