Merge remote branch 'origin/4.6' into lighthouse

Conflicts:
	configure
	src/plugins/graphicssystems/graphicssystems.pro

27 files changed, 2670 insertions, 1385 deletions

diff --git a/src/gui/graphicsview/qgraph_p.h b/src/gui/graphicsview/qgraph_p.h
index f1fa185..0a2bf27 100644
--- a/src/gui/graphicsview/qgraph_p.h
+++ b/src/gui/graphicsview/qgraph_p.h
@@ -201,11 +201,6 @@ public:
         return l;
     }
 
-    void setRootVertex(Vertex *vertex)
-    {
-        userVertex = vertex;
-    }
-
     QSet<Vertex*> vertices() const {
         QSet<Vertex *> setOfVertices;
         for (const_iterator it = constBegin(); it != constEnd(); ++it) {
@@ -241,7 +236,7 @@ public:
                 EdgeData *data = edgeData(v, v1);
                 bool forward = data->from == v;
                 if (forward) {
-                    edges += QString::fromAscii("%1->%2 [label=\"[%3,%4,%5]\" dir=both color=\"#000000:#a0a0a0\"] \n")
+                    edges += QString::fromAscii("\"%1\"->\"%2\" [label=\"[%3,%4,%5]\" dir=both color=\"#000000:#a0a0a0\"] \n")
                         .arg(v->toString())
                         .arg(v1->toString())
                         .arg(data->minSize)
@@ -250,17 +245,12 @@ public:
                         ;
                 }
             }
-            strVertices += QString::fromAscii("%1 [label=\"%2\"]\n").arg(v->toString()).arg(v->toString());
+            strVertices += QString::fromAscii("\"%1\" [label=\"%2\"]\n").arg(v->toString()).arg(v->toString());
         }
         return QString::fromAscii("%1\n%2\n").arg(strVertices).arg(edges);
     }
 #endif
 
-    Vertex *rootVertex() const
-    {
-        return userVertex;
-    }
-
 protected:
     void createDirectedEdge(Vertex *from, Vertex *to, EdgeData *data)
     {
@@ -286,8 +276,6 @@ protected:
     }
 
 private:
-    Vertex *userVertex;
-
     QHash<Vertex *, QHash<Vertex *, EdgeData *> *> m_graph;
 };
 
diff --git a/src/gui/graphicsview/qgraphicsanchorlayout.cpp b/src/gui/graphicsview/qgraphicsanchorlayout.cpp
index ffbb67c..7e5929e 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout.cpp
+++ b/src/gui/graphicsview/qgraphicsanchorlayout.cpp
@@ -48,36 +48,73 @@
     \ingroup geomanagement
     \ingroup graphicsview-api
 
-    The anchor layout is a layout where one can specify how widgets should be placed relative to
-    each other. The specification is called an anchor, and it is set up by calling anchor().
+    The anchor layout allows developers to specify how widgets should be placed relative to
+    each other, and to the layout itself. The specification is made by adding anchors to the
+    layout by calling addAnchor(), addAnchors() or addCornerAnchors().
+
+    Existing anchors in the layout can be accessed with the anchor() function.
+    Items that are anchored are automatically added to the layout, and if items
+    are removed, all their anchors will be automatically removed.
+
+    \beginfloatleft
+    \inlineimage simpleanchorlayout-example.png Using an anchor layout to align simple colored widgets.
+    \endfloat
+
     Anchors are always set up between edges of an item, where the "center" is also considered to
-    be an edge. Considering this example:
-    \code
-        QGraphicsAnchorLayout *l = new QGraphicsAnchorLayout;
-        QGraphicsWidget *a = new QGraphicsWidget;
-        QGraphicsWidget *b = new QGraphicsWidget;
-        l->anchor(a, Qt::AnchorRight, b, Qt::AnchorLeft);
-    \endcode
-
-    Here is the right edge of item A anchored to the left edge of item B, with the result that
-    item B will be placed to the right of item A, with a spacing between A and B. If the
-    spacing is negative, the items will overlap to some extent. Items that are anchored are
-    automatically added to the layout, and if items are removed, all their anchors will be
-    automatically removed
-
-    \section1 Size Hints and Size Policies in QGraphicsAnchorLayout
-
-    QGraphicsAnchorLayout respects each item's size hints and size policies. However it does
-    not respect stretch factors currently. This might change in the future, so please refrain
-    from using stretch factors in anchor layout to avoid any future regressions.
-
-    \section1 Spacing within QGraphicsAnchorLayout
-
-    Between the items, the layout can distribute some space. If the spacing has not been
-    explicitly specified, the actual amount of space will usually be 0, but if the first edge
-    is the "opposite" of the second edge (i.e. Right is anchored to Left or vice-versa), the
-    size of the anchor will be queried from the style through the pixelMetric
-    PM_LayoutHorizontalSpacing (or PM_LayoutVerticalSpacing for vertical anchors).
+    be an edge. Consider the following example:
+
+    \snippet examples/graphicsview/simpleanchorlayout/main.cpp adding anchors
+
+    Here, the right edge of item \c a is anchored to the left edge of item \c b and the bottom
+    edge of item \c a is anchored to the top edge of item \c b, with the result that
+    item \c b will be placed diagonally to the right and below item \c b.
+
+    The addCornerAnchors() function provides a simpler way of anchoring the corners
+    of two widgets than the two individual calls to addAnchor() shown in the code
+    above. Here, we see how a widget can be anchored to the top-left corner of the enclosing
+    layout:
+
+    \snippet examples/graphicsview/simpleanchorlayout/main.cpp adding a corner anchor
+
+    In cases where anchors are used to match the widths or heights of widgets, it is
+    convenient to use the addAnchors() function. As with the other functions for specifying
+    anchors, it can also be used to anchor a widget to a layout.
+
+    \clearfloat
+    \section1 Size Hints and Size Policies in an Anchor Layout
+
+    QGraphicsAnchorLayout respects each item's size hints and size policies.
+    Note that there are some properties of QSizePolicy that are \l{Known issues}{not respected}.
+
+    \section1 Spacing within an Anchor Layout
+
+    The layout may distribute some space between the items. If the spacing has not been
+    explicitly specified, the actual amount of space will usually be 0.
+
+    However, if the first edge is the \e opposite of the second edge (e.g., the right edge
+    of the first widget is anchored to the left edge of the second widget), the size of the
+    anchor will be queried from the style through a pixel metric:
+    \l{QStyle::}{PM_LayoutHorizontalSpacing} for horizontal anchors and
+    \l{QStyle::}{PM_LayoutVerticalSpacing} for vertical anchors.
+
+    If the spacing is negative, the items will overlap to some extent.
+
+
+    \section1 Known issues
+    There are some features that QGraphicsAnchorLayout currently does not support.
+    This might change in the future, so avoid using these features if you want to
+    avoid any future regressions in behaviour:
+    \list
+
+    \o Stretch factors are not respected.
+
+    \o QSizePolicy::ExpandFlag is not respected.
+
+    \o Height for width is not respected.
+
+    \endlist
+
+    \sa QGraphicsLinearLayout, QGraphicsGridLayout, QGraphicsLayout
 */
 
 /*!
@@ -99,7 +136,7 @@
 
 */
 #include "qgraphicsanchorlayout_p.h"
-
+#ifndef QT_NO_GRAPHICSVIEW
 QT_BEGIN_NAMESPACE
 
 QGraphicsAnchor::QGraphicsAnchor(QGraphicsAnchorLayout *parentLayout)
@@ -118,13 +155,40 @@ QGraphicsAnchor::~QGraphicsAnchor()
 }
 
 /*!
+    \property QGraphicsAnchor::sizePolicy
+    \brief the size policy for the QGraphicsAnchor.
+
+    By setting the size policy on an anchor you can configure how the item can resize itself
+    from its preferred spacing. For instance, if the anchor has the size policy
+    QSizePolicy::Minimum, the spacing is the minimum size of the anchor. However, its size
+    can grow up to the anchors maximum size. If the default size policy is QSizePolicy::Fixed,
+    the anchor can neither grow or shrink, which means that the only size the anchor can have
+    is the spacing. QSizePolicy::Fixed is the default size policy.
+    QGraphicsAnchor always has a minimum spacing of 0 and a very large maximum spacing.
+
+    \sa QGraphicsAnchor::spacing
+*/
+
+void QGraphicsAnchor::setSizePolicy(QSizePolicy::Policy policy)
+{
+    Q_D(QGraphicsAnchor);
+    d->setSizePolicy(policy);
+}
+
+QSizePolicy::Policy QGraphicsAnchor::sizePolicy() const
+{
+    Q_D(const QGraphicsAnchor);
+    return d->sizePolicy;
+}
+
+/*!
     \property QGraphicsAnchor::spacing
-    \brief the space between items in the QGraphicsAnchorLayout.
+    \brief the preferred space between items in the QGraphicsAnchorLayout.
 
     Depending on the anchor type, the default spacing is either
     0 or a value returned from the style.
 
-    \sa QGraphicsAnchorLayout::anchor()
+    \sa QGraphicsAnchorLayout::addAnchor()
 */
 void QGraphicsAnchor::setSpacing(qreal spacing)
 {
@@ -188,7 +252,7 @@ QGraphicsAnchorLayout::~QGraphicsAnchorLayout()
     If there is already an anchor between the edges, the the new anchor will replace the old one.
 
     \a firstItem and \a secondItem are automatically added to the layout if they are not part
-    of the layout. This means that count() can increase with up to 2.
+    of the layout. This means that count() can increase by up to 2.
 
     The spacing an anchor will get depends on the type of anchor. For instance, anchors from the
     Right edge of one item to the Left edge of another (or vice versa) will use the default
@@ -198,7 +262,10 @@ QGraphicsAnchorLayout::~QGraphicsAnchorLayout()
 
     The spacing can also be set manually by using QGraphicsAnchor::setSpacing() method.
 
-    \sa addCornerAnchors(), addAnchors()
+    Calling this function where \a firstItem or \a secondItem are ancestors of the layout have
+    undefined behaviour.
+
+    \sa addAnchors(), addCornerAnchors()
  */
 QGraphicsAnchor *
 QGraphicsAnchorLayout::addAnchor(QGraphicsLayoutItem *firstItem, Qt::AnchorPoint firstEdge,
@@ -223,29 +290,26 @@ QGraphicsAnchorLayout::anchor(QGraphicsLayoutItem *firstItem, Qt::AnchorPoint fi
 }
 
 /*!
-    Creates two anchors between \a firstItem and \a secondItem, where one is for the horizontal
-    edge and another one for the vertical edge that the corners \a firstCorner and \a
-    secondCorner specifies.
-    The magnitude of the anchors is picked up from the style.
+    Creates two anchors between \a firstItem and \a secondItem specified by the corners,
+    \a firstCorner and \a secondCorner, where one is for the horizontal edge and another
+    one for the vertical edge.
+
+    This is a convenience function, since anchoring corners can be expressed as anchoring
+    two edges. For instance:
 
-    This is a convenience function, since anchoring corners can be expressed as anchoring two edges.
-    For instance,
-    \code
-      layout->addAnchor(layout, Qt::AnchorTop, b, Qt::AnchorTop);
-      layout->addAnchor(layout, Qt::AnchorLeft, b, Qt::AnchorLeft);
-    \endcode
+    \snippet examples/graphicsview/simpleanchorlayout/main.cpp adding a corner anchor in two steps
 
-    has the same effect as
+    This can also be achieved with the following line of code:
 
-    \code
-      layout->addCornerAnchors(layout, Qt::TopLeft, b, Qt::TopLeft);
-    \endcode
+    \snippet examples/graphicsview/simpleanchorlayout/main.cpp adding a corner anchor
 
     If there is already an anchor between the edge pairs, it will be replaced by the anchors that
     this function specifies.
 
     \a firstItem and \a secondItem are automatically added to the layout if they are not part of the
-    layout. This means that count() can increase with up to 2.
+    layout. This means that count() can increase by up to 2.
+
+    \sa addAnchor(), addAnchors()
 */
 void QGraphicsAnchorLayout::addCornerAnchors(QGraphicsLayoutItem *firstItem,
                                              Qt::Corner firstCorner,
@@ -272,17 +336,16 @@ void QGraphicsAnchorLayout::addCornerAnchors(QGraphicsLayoutItem *firstItem,
     edges of \a secondItem, so that \a firstItem has the same size as
     \a secondItem in the dimensions specified by \a orientations.
 
-    Calling this convenience function with the following arguments
-    \code
-    l->addAnchors(firstItem, secondItem, Qt::Horizontal)
-    \endcode
+    For example, the following example anchors the left and right edges of two items
+    to match their widths:
+
+    \snippet examples/graphicsview/simpleanchorlayout/main.cpp adding anchors to match sizes in two steps
+
+    This can also be achieved using the following line of code:
 
-    is the same as
+    \snippet examples/graphicsview/simpleanchorlayout/main.cpp adding anchors to match sizes
 
-    \code
-    l->addAnchor(firstItem, Qt::AnchorLeft, secondItem, Qt::AnchorLeft);
-    l->addAnchor(firstItem, Qt::AnchorRight, secondItem, Qt::AnchorRight);
-    \endcode
+    \sa addAnchor(), addCornerAnchors()
 */
 void QGraphicsAnchorLayout::addAnchors(QGraphicsLayoutItem *firstItem,
                                        QGraphicsLayoutItem *secondItem,
@@ -306,6 +369,13 @@ void QGraphicsAnchorLayout::addAnchors(QGraphicsLayoutItem *firstItem,
 void QGraphicsAnchorLayout::setHorizontalSpacing(qreal spacing)
 {
     Q_D(QGraphicsAnchorLayout);
+
+    // ### We don't support negative spacing yet
+    if (spacing < 0) {
+        spacing = 0;
+        qWarning() << "QGraphicsAnchorLayout does not support negative spacing.";
+    }
+
     d->spacings[0] = spacing;
     invalidate();
 }
@@ -318,6 +388,13 @@ void QGraphicsAnchorLayout::setHorizontalSpacing(qreal spacing)
 void QGraphicsAnchorLayout::setVerticalSpacing(qreal spacing)
 {
     Q_D(QGraphicsAnchorLayout);
+
+    // ### We don't support negative spacing yet
+    if (spacing < 0) {
+        spacing = 0;
+        qWarning() << "QGraphicsAnchorLayout does not support negative spacing.";
+    }
+
     d->spacings[1] = spacing;
     invalidate();
 }
@@ -327,11 +404,23 @@ void QGraphicsAnchorLayout::setVerticalSpacing(qreal spacing)
 
     If an item is anchored with no spacing associated with the anchor, it will use the default
     spacing.
+
+    Currently QGraphicsAnchorLayout does not support negative default spacings.
+
     \sa setHorizontalSpacing(), setVerticalSpacing()
 */
 void QGraphicsAnchorLayout::setSpacing(qreal spacing)
 {
     Q_D(QGraphicsAnchorLayout);
+
+    // ### Currently we do not support negative anchors inside the graph.
+    // To avoid those being created by a negative spacing, we must
+    // make this test.
+    if (spacing < 0) {
+        spacing = 0;
+        qWarning() << "QGraphicsAnchorLayout does not support negative spacing.";
+    }
+
     d->spacings[0] = d->spacings[1] = spacing;
     invalidate();
 }
@@ -344,7 +433,7 @@ void QGraphicsAnchorLayout::setSpacing(qreal spacing)
 qreal QGraphicsAnchorLayout::horizontalSpacing() const
 {
     Q_D(const QGraphicsAnchorLayout);
-    return d->effectiveSpacing(QGraphicsAnchorLayoutPrivate::Horizontal);
+    return d->styleInfo().defaultSpacing(Qt::Horizontal);
 }
 
 /*!
@@ -355,7 +444,7 @@ qreal QGraphicsAnchorLayout::horizontalSpacing() const
 qreal QGraphicsAnchorLayout::verticalSpacing() const
 {
     Q_D(const QGraphicsAnchorLayout);
-    return d->effectiveSpacing(QGraphicsAnchorLayoutPrivate::Vertical);
+    return d->styleInfo().defaultSpacing(Qt::Vertical);
 }
 
 /*!
@@ -388,9 +477,6 @@ void QGraphicsAnchorLayout::removeAt(int index)
         return;
 
     // Removing an item affects both horizontal and vertical graphs
-    d->restoreSimplifiedGraph(QGraphicsAnchorLayoutPrivate::Horizontal);
-    d->restoreSimplifiedGraph(QGraphicsAnchorLayoutPrivate::Vertical);
-
     d->removeCenterConstraints(item, QGraphicsAnchorLayoutPrivate::Horizontal);
     d->removeCenterConstraints(item, QGraphicsAnchorLayoutPrivate::Vertical);
     d->removeAnchors(item);
@@ -425,7 +511,8 @@ void QGraphicsAnchorLayout::invalidate()
 {
     Q_D(QGraphicsAnchorLayout);
     QGraphicsLayout::invalidate();
-    d->calculateGraphCacheDirty = 1;
+    d->calculateGraphCacheDirty = true;
+    d->styleInfoDirty = true;
 }
 
 /*!
@@ -459,3 +546,4 @@ QSizeF QGraphicsAnchorLayout::sizeHint(Qt::SizeHint which, const QSizeF &constra
 }
 
 QT_END_NAMESPACE
+#endif //QT_NO_GRAPHICSVIEW
diff --git a/src/gui/graphicsview/qgraphicsanchorlayout.h b/src/gui/graphicsview/qgraphicsanchorlayout.h
index 99dbf92..063639e 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout.h
+++ b/src/gui/graphicsview/qgraphicsanchorlayout.h
@@ -62,10 +62,13 @@ class Q_GUI_EXPORT QGraphicsAnchor : public QObject
 {
     Q_OBJECT
     Q_PROPERTY(qreal spacing READ spacing WRITE setSpacing RESET unsetSpacing)
+    Q_PROPERTY(QSizePolicy::Policy sizePolicy READ sizePolicy WRITE setSizePolicy)
 public:
     void setSpacing(qreal spacing);
     void unsetSpacing();
     qreal spacing() const;
+    void setSizePolicy(QSizePolicy::Policy policy);
+    QSizePolicy::Policy sizePolicy() const;
     ~QGraphicsAnchor();
 private:
     QGraphicsAnchor(QGraphicsAnchorLayout *parent);
@@ -73,6 +76,7 @@ private:
     Q_DECLARE_PRIVATE(QGraphicsAnchor)
 
     friend class QGraphicsAnchorLayoutPrivate;
+    friend struct AnchorData;
 };
 
 class Q_GUI_EXPORT QGraphicsAnchorLayout : public QGraphicsLayout
diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
index f9b5c8c..fb67278 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -40,6 +40,7 @@
 ****************************************************************************/
 
 #include <QtGui/qwidget.h>
+#include <QtGui/qapplication.h>
 #include <QtCore/qlinkedlist.h>
 #include <QtCore/qstack.h>
 
@@ -48,12 +49,14 @@
 #endif
 
 #include "qgraphicsanchorlayout_p.h"
-
+#ifndef QT_NO_GRAPHICSVIEW
 QT_BEGIN_NAMESPACE
 
 
 QGraphicsAnchorPrivate::QGraphicsAnchorPrivate(int version)
-    : QObjectPrivate(version), layoutPrivate(0), data(0)
+    : QObjectPrivate(version), layoutPrivate(0), data(0),
+      sizePolicy(QSizePolicy::Fixed), preferredSize(0),
+      hasSize(true), reversed(false)
 {
 }
 
@@ -62,58 +65,78 @@ QGraphicsAnchorPrivate::~QGraphicsAnchorPrivate()
     layoutPrivate->removeAnchor(data->from, data->to);
 }
 
+void QGraphicsAnchorPrivate::setSizePolicy(QSizePolicy::Policy policy)
+{
+    if (sizePolicy != policy) {
+        sizePolicy = policy;
+        layoutPrivate->q_func()->invalidate();
+    }
+}
+
 void QGraphicsAnchorPrivate::setSpacing(qreal value)
 {
-    if (data) {
-        layoutPrivate->setAnchorSize(data, &value);
-    } else {
+    if (!data) {
         qWarning("QGraphicsAnchor::setSpacing: The anchor does not exist.");
+        return;
+    }
+
+    const qreal rawValue = reversed ? -preferredSize : preferredSize;
+    if (hasSize && (rawValue == value))
+        return;
+
+    // The anchor has an user-defined size
+    hasSize = true;
+
+    // The simplex solver cannot handle negative sizes. To workaround that,
+    // if value is less than zero, we reverse the anchor and set the absolute
+    // value;
+    if (value >= 0) {
+        preferredSize = value;
+        if (reversed)
+            qSwap(data->from, data->to);
+        reversed = false;
+    } else {
+        preferredSize = -value;
+        if (!reversed)
+            qSwap(data->from, data->to);
+        reversed = true;
     }
+
+    layoutPrivate->q_func()->invalidate();
 }
 
 void QGraphicsAnchorPrivate::unsetSpacing()
 {
-    if (data) {
-        layoutPrivate->setAnchorSize(data, 0);
-    } else {
+    if (!data) {
         qWarning("QGraphicsAnchor::setSpacing: The anchor does not exist.");
+        return;
     }
+
+    // Return to standard direction
+    hasSize = false;
+    if (reversed)
+        qSwap(data->from, data->to);
+    reversed = false;
+
+    layoutPrivate->q_func()->invalidate();
 }
 
 qreal QGraphicsAnchorPrivate::spacing() const
 {
-    qreal size = 0;
-    if (data) {
-        layoutPrivate->anchorSize(data, 0, &size, 0);
-    } else {
+    if (!data) {
         qWarning("QGraphicsAnchor::setSpacing: The anchor does not exist.");
+        return 0;
     }
-    return size;
+
+    return reversed ? -preferredSize : preferredSize;
 }
 
 
-static void sizeHintsFromItem(QGraphicsLayoutItem *item,
-                             const QGraphicsAnchorLayoutPrivate::Orientation orient,
-                             qreal *minSize, qreal *prefSize,
-                             qreal *expSize, qreal *maxSize)
+static void internalSizeHints(QSizePolicy::Policy policy,
+                              qreal minSizeHint, qreal prefSizeHint, qreal maxSizeHint,
+                              qreal *minSize, qreal *prefSize,
+                              qreal *maxSize)
 {
-    QSizePolicy::Policy policy;
-    qreal minSizeHint;
-    qreal prefSizeHint;
-    qreal maxSizeHint;
-
-    if (orient == QGraphicsAnchorLayoutPrivate::Horizontal) {
-        policy = item->sizePolicy().horizontalPolicy();
-        minSizeHint = item->effectiveSizeHint(Qt::MinimumSize).width();
-        prefSizeHint = item->effectiveSizeHint(Qt::PreferredSize).width();
-        maxSizeHint = item->effectiveSizeHint(Qt::MaximumSize).width();
-    } else {
-        policy = item->sizePolicy().verticalPolicy();
-        minSizeHint = item->effectiveSizeHint(Qt::MinimumSize).height();
-        prefSizeHint = item->effectiveSizeHint(Qt::PreferredSize).height();
-        maxSizeHint = item->effectiveSizeHint(Qt::MaximumSize).height();
-    }
-
     // minSize, prefSize and maxSize are initialized
     // with item's preferred Size: this is QSizePolicy::Fixed.
     //
@@ -139,52 +162,77 @@ static void sizeHintsFromItem(QGraphicsLayoutItem *item,
 
     // Note that these two initializations are affected by the previous flags
     if (policy & QSizePolicy::IgnoreFlag)
-        *prefSize = *maxSize;
+        *prefSize = *minSize;
     else
         *prefSize = prefSizeHint;
-
-    if (policy & QSizePolicy::ExpandFlag)
-        *expSize = *maxSize;
-    else
-        *expSize = *prefSize;
 }
 
-void AnchorData::refreshSizeHints(qreal effectiveSpacing)
+void AnchorData::refreshSizeHints(const QLayoutStyleInfo *styleInfo)
 {
-    const bool isInternalAnchor = from->m_item == to->m_item;
-
-    if (isInternalAnchor) {
-        const QGraphicsAnchorLayoutPrivate::Orientation orient =
-            QGraphicsAnchorLayoutPrivate::edgeOrientation(from->m_edge);
+    QSizePolicy::Policy policy;
+    qreal minSizeHint;
+    qreal prefSizeHint;
+    qreal maxSizeHint;
 
+    if (item) {
+        // It is an internal anchor, fetch size information from the item
         if (isLayoutAnchor) {
             minSize = 0;
             prefSize = 0;
-            expSize = 0;
             maxSize = QWIDGETSIZE_MAX;
+            if (isCenterAnchor)
+                maxSize /= 2;
+            return;
         } else {
-            QGraphicsLayoutItem *item = from->m_item;
-            sizeHintsFromItem(item, orient, &minSize, &prefSize, &expSize, &maxSize);
-        }
-
-        const Qt::AnchorPoint centerEdge =
-            QGraphicsAnchorLayoutPrivate::pickEdge(Qt::AnchorHorizontalCenter, orient);
-        bool hasCenter = (from->m_edge == centerEdge || to->m_edge == centerEdge);
+            if (orientation == QGraphicsAnchorLayoutPrivate::Horizontal) {
+                policy = item->sizePolicy().horizontalPolicy();
+                minSizeHint = item->effectiveSizeHint(Qt::MinimumSize).width();
+                prefSizeHint = item->effectiveSizeHint(Qt::PreferredSize).width();
+                maxSizeHint = item->effectiveSizeHint(Qt::MaximumSize).width();
+            } else {
+                policy = item->sizePolicy().verticalPolicy();
+                minSizeHint = item->effectiveSizeHint(Qt::MinimumSize).height();
+                prefSizeHint = item->effectiveSizeHint(Qt::PreferredSize).height();
+                maxSizeHint = item->effectiveSizeHint(Qt::MaximumSize).height();
+            }
 
-        if (hasCenter) {
-            minSize /= 2;
-            prefSize /= 2;
-            expSize /= 2;
-            maxSize /= 2;
+            if (isCenterAnchor) {
+                minSizeHint /= 2;
+                prefSizeHint /= 2;
+                maxSizeHint /= 2;
+            }
         }
-
-    } else if (!hasSize) {
-        // Anchor has no size defined, use given default information
-        minSize = effectiveSpacing;
-        prefSize = effectiveSpacing;
-        expSize = effectiveSpacing;
-        maxSize = effectiveSpacing;
+    } else {
+        // It is a user-created anchor, fetch size information from the associated QGraphicsAnchor
+        Q_ASSERT(graphicsAnchor);
+        QGraphicsAnchorPrivate *anchorPrivate = graphicsAnchor->d_func();
+        policy = anchorPrivate->sizePolicy;
+        minSizeHint = 0;
+        if (anchorPrivate->hasSize) {
+            // One can only configure the preferred size of a normal anchor. Their minimum and
+            // maximum "size hints" are always 0 and QWIDGETSIZE_MAX, correspondingly. However,
+            // their effective size hints might be narrowed down due to their size policies.
+            prefSizeHint = anchorPrivate->preferredSize;
+        } else {
+            const Qt::Orientation orient = Qt::Orientation(QGraphicsAnchorLayoutPrivate::edgeOrientation(from->m_edge) + 1);
+            qreal s = styleInfo->defaultSpacing(orient);
+            if (s < 0) {
+                QSizePolicy::ControlType controlTypeFrom = from->m_item->sizePolicy().controlType();
+                QSizePolicy::ControlType controlTypeTo = to->m_item->sizePolicy().controlType();
+                s = styleInfo->perItemSpacing(controlTypeFrom, controlTypeTo, orient);
+
+                // ### Currently we do not support negative anchors inside the graph.
+                // To avoid those being created by a negative style spacing, we must
+                // make this test.
+                if (s < 0)
+                    s = 0;
+            }
+            prefSizeHint = s;
+        }
+        maxSizeHint = QWIDGETSIZE_MAX;
     }
+    internalSizeHints(policy, minSizeHint, prefSizeHint, maxSizeHint,
+                      &minSize, &prefSize, &maxSize);
 
     // Set the anchor effective sizes to preferred.
     //
@@ -195,52 +243,85 @@ void AnchorData::refreshSizeHints(qreal effectiveSpacing)
     // recalculate and override the values we set here.
     sizeAtMinimum = prefSize;
     sizeAtPreferred = prefSize;
-    sizeAtExpanding = prefSize;
     sizeAtMaximum = prefSize;
 }
 
 void ParallelAnchorData::updateChildrenSizes()
 {
-    firstEdge->sizeAtMinimum = secondEdge->sizeAtMinimum = sizeAtMinimum;
-    firstEdge->sizeAtPreferred = secondEdge->sizeAtPreferred = sizeAtPreferred;
-    firstEdge->sizeAtExpanding = secondEdge->sizeAtExpanding = sizeAtExpanding;
-    firstEdge->sizeAtMaximum = secondEdge->sizeAtMaximum = sizeAtMaximum;
+    firstEdge->sizeAtMinimum = sizeAtMinimum;
+    firstEdge->sizeAtPreferred = sizeAtPreferred;
+    firstEdge->sizeAtMaximum = sizeAtMaximum;
+
+    // We have the convention that the first children will define the direction of the
+    // pararell group. So we can check whether the second edge is "forward" in relation
+    // to the group if it have the same direction as the first edge. Note that we don't
+    // use 'this->from' because it might be changed by vertex simplification.
+    const bool secondForward = (firstEdge->from == secondEdge->from);
+
+    if (secondForward) {
+        secondEdge->sizeAtMinimum = sizeAtMinimum;
+        secondEdge->sizeAtPreferred = sizeAtPreferred;
+        secondEdge->sizeAtMaximum = sizeAtMaximum;
+    } else {
+        secondEdge->sizeAtMinimum = -sizeAtMinimum;
+        secondEdge->sizeAtPreferred = -sizeAtPreferred;
+        secondEdge->sizeAtMaximum = -sizeAtMaximum;
+    }
 
     firstEdge->updateChildrenSizes();
     secondEdge->updateChildrenSizes();
 }
 
-void ParallelAnchorData::refreshSizeHints(qreal effectiveSpacing)
+bool ParallelAnchorData::calculateSizeHints()
 {
-    refreshSizeHints_helper(effectiveSpacing);
-}
+    // Note that parallel groups can lead to unfeasibility, so during calculation, we can
+    // find out one unfeasibility. Because of that this method return boolean. This can't
+    // happen in sequential, so there the method is void.
 
-void ParallelAnchorData::refreshSizeHints_helper(qreal effectiveSpacing,
-                                                 bool refreshChildren)
-{
-    if (refreshChildren) {
-        firstEdge->refreshSizeHints(effectiveSpacing);
-        secondEdge->refreshSizeHints(effectiveSpacing);
-    }
+    // Account for parallel anchors where the second edge is backwards.
+    // We rely on the fact that a forward anchor of sizes min, pref, max is equivalent
+    // to a backwards anchor of size (-max, -pref, -min)
 
-    // ### should we warn if the parallel connection is invalid?
-    // e.g. 1-2-3 with 10-20-30, the minimum of the latter is
-    // bigger than the maximum of the former.
+    // Also see comments in updateChildrenSizes().
+    const bool secondForward = (firstEdge->from == secondEdge->from);
+    const qreal secondMin = secondForward ? secondEdge->minSize : -secondEdge->maxSize;
+    const qreal secondPref = secondForward ? secondEdge->prefSize : -secondEdge->prefSize;
+    const qreal secondMax = secondForward ? secondEdge->maxSize : -secondEdge->minSize;
 
-    minSize = qMax(firstEdge->minSize, secondEdge->minSize);
-    maxSize = qMin(firstEdge->maxSize, secondEdge->maxSize);
+    minSize = qMax(firstEdge->minSize, secondMin);
+    maxSize = qMin(firstEdge->maxSize, secondMax);
 
-    expSize = qMax(firstEdge->expSize, secondEdge->expSize);
-    expSize = qMin(expSize, maxSize);
+    // This condition means that the maximum size of one anchor being simplified is smaller than
+    // the minimum size of the other anchor. The consequence is that there won't be a valid size
+    // for this parallel setup.
+    if (minSize > maxSize) {
+        return false;
+    }
+
+    // The equivalent preferred Size of a parallel anchor is calculated as to
+    // reduce the deviation from the original preferred sizes _and_ to avoid shrinking
+    // items below their preferred sizes, unless strictly needed.
 
-    prefSize = qMax(firstEdge->prefSize, secondEdge->prefSize);
-    prefSize = qMin(prefSize, expSize);
+    // ### This logic only holds if all anchors in the layout are "well-behaved" in the
+    // following terms:
+    //
+    // - There are no negative-sized anchors
+    // - All sequential anchors are composed of children in the same direction as the
+    //   sequential anchor itself
+    //
+    // With these assumptions we can grow a child knowing that no hidden items will
+    // have to shrink as the result of that.
+    // If any of these does not hold, we have a situation where the ParallelAnchor
+    // does not have enough information to calculate its equivalent prefSize.
+    prefSize = qMax(firstEdge->prefSize, secondPref);
+    prefSize = qMin(prefSize, maxSize);
 
     // See comment in AnchorData::refreshSizeHints() about sizeAt* values
     sizeAtMinimum = prefSize;
     sizeAtPreferred = prefSize;
-    sizeAtExpanding = prefSize;
     sizeAtMaximum = prefSize;
+
+    return true;
 }
 
 /*!
@@ -250,44 +331,52 @@ void ParallelAnchorData::refreshSizeHints_helper(qreal effectiveSpacing,
      0 is at Preferred
      1 is at Maximum
 */
-static qreal getFactor(qreal value, qreal min, qreal pref, qreal max)
-{
-    // ### Maybe remove some of the assertions? (since outside is asserting us)
-    Q_ASSERT(value > min || qFuzzyCompare(value, min));
-    Q_ASSERT(value < max || qFuzzyCompare(value, max));
-
-    if (qFuzzyCompare(value, min)) {
-        return -1.0;
-    } else if (qFuzzyCompare(value, pref)) {
-        return 0.0;
-    } else if (qFuzzyCompare(value, max)) {
-        return 1.0;
-    } else if (value < pref) {
-        // Since value < pref and value != pref and min <= value,
-        // we can assert that min < pref.
-        Q_ASSERT(min < pref);
-        return (value - min) / (pref - min) - 1;
+static QPair<QGraphicsAnchorLayoutPrivate::Interval, qreal> getFactor(qreal value, qreal min,
+                                                                      qreal pref, qreal max)
+{
+    QGraphicsAnchorLayoutPrivate::Interval interval;
+    qreal lower;
+    qreal upper;
+
+    if (value < pref) {
+        interval = QGraphicsAnchorLayoutPrivate::MinToPreferred;
+        lower = min;
+        upper = pref;
     } else {
-        // Since value > pref and value != pref and max >= value,
-        // we can assert that max > pref.
-        Q_ASSERT(max > pref);
-        return (value - pref) / (max - pref);
+        interval = QGraphicsAnchorLayoutPrivate::PreferredToMax;
+        lower = pref;
+        upper = max;
     }
+
+    qreal progress;
+    if (upper == lower) {
+        progress = 0;
+    } else {
+        progress = (value - lower) / (upper - lower);
+    }
+
+    return qMakePair(interval, progress);
 }
 
-static qreal getExpandingFactor(const qreal &expSize, const qreal &sizeAtPreferred,
-                                const qreal &sizeAtExpanding, const qreal &sizeAtMaximum)
+static qreal interpolate(const QPair<QGraphicsAnchorLayoutPrivate::Interval, qreal> &factor,
+                         qreal min, qreal pref,
+                         qreal max)
 {
-    const qreal lower = qMin(sizeAtPreferred, sizeAtMaximum);
-    const qreal upper = qMax(sizeAtPreferred, sizeAtMaximum);
-    const qreal boundedExpSize = qBound(lower, expSize, upper);
+    qreal lower;
+    qreal upper;
 
-    const qreal bandSize = sizeAtMaximum - boundedExpSize;
-    if (bandSize == 0) {
-        return 0;
-    } else {
-        return (sizeAtExpanding - boundedExpSize) / bandSize;
+    switch (factor.first) {
+    case QGraphicsAnchorLayoutPrivate::MinToPreferred:
+        lower = min;
+        upper = pref;
+        break;
+    case QGraphicsAnchorLayoutPrivate::PreferredToMax:
+        lower = pref;
+        upper = max;
+        break;
     }
+
+    return lower + factor.second * (upper - lower);
 }
 
 void SequentialAnchorData::updateChildrenSizes()
@@ -295,74 +384,52 @@ void SequentialAnchorData::updateChildrenSizes()
     // ### REMOVE ME
     // ### check whether we are guarantee to get those or we need to warn stuff at this
     // point.
-    Q_ASSERT(sizeAtMinimum > minSize || qFuzzyCompare(sizeAtMinimum, minSize));
-    Q_ASSERT(sizeAtMinimum < maxSize || qFuzzyCompare(sizeAtMinimum, maxSize));
-    Q_ASSERT(sizeAtPreferred > minSize || qFuzzyCompare(sizeAtPreferred, minSize));
-    Q_ASSERT(sizeAtPreferred < maxSize || qFuzzyCompare(sizeAtPreferred, maxSize));
-    Q_ASSERT(sizeAtExpanding > minSize || qFuzzyCompare(sizeAtExpanding, minSize));
-    Q_ASSERT(sizeAtExpanding < maxSize || qFuzzyCompare(sizeAtExpanding, maxSize));
-    Q_ASSERT(sizeAtMaximum > minSize || qFuzzyCompare(sizeAtMaximum, minSize));
-    Q_ASSERT(sizeAtMaximum < maxSize || qFuzzyCompare(sizeAtMaximum, maxSize));
+    Q_ASSERT(sizeAtMinimum > minSize || qAbs(sizeAtMinimum - minSize) < 0.00000001);
+    Q_ASSERT(sizeAtPreferred > minSize || qAbs(sizeAtPreferred - minSize) < 0.00000001);
+    Q_ASSERT(sizeAtMaximum > minSize || qAbs(sizeAtMaximum - minSize) < 0.00000001);
+
+    // These may be false if this anchor was in parallel with the layout stucture
+    // Q_ASSERT(sizeAtMinimum < maxSize || qAbs(sizeAtMinimum - maxSize) < 0.00000001);
+    // Q_ASSERT(sizeAtPreferred < maxSize || qAbs(sizeAtPreferred - maxSize) < 0.00000001);
+    // Q_ASSERT(sizeAtMaximum < maxSize || qAbs(sizeAtMaximum - maxSize) < 0.00000001);
 
     // Band here refers if the value is in the Minimum To Preferred
     // band (the lower band) or the Preferred To Maximum (the upper band).
 
-    const qreal minFactor = getFactor(sizeAtMinimum, minSize, prefSize, maxSize);
-    const qreal prefFactor = getFactor(sizeAtPreferred, minSize, prefSize, maxSize);
-    const qreal maxFactor = getFactor(sizeAtMaximum, minSize, prefSize, maxSize);
-    const qreal expFactor = getExpandingFactor(expSize, sizeAtPreferred, sizeAtExpanding, sizeAtMaximum);
+    const QPair<QGraphicsAnchorLayoutPrivate::Interval, qreal> minFactor =
+        getFactor(sizeAtMinimum, minSize, prefSize, maxSize);
+    const QPair<QGraphicsAnchorLayoutPrivate::Interval, qreal> prefFactor =
+        getFactor(sizeAtPreferred, minSize, prefSize, maxSize);
+    const QPair<QGraphicsAnchorLayoutPrivate::Interval, qreal> maxFactor =
+        getFactor(sizeAtMaximum, minSize, prefSize, maxSize);
 
     for (int i = 0; i < m_edges.count(); ++i) {
         AnchorData *e = m_edges.at(i);
 
-        qreal bandSize = minFactor > 0 ? e->maxSize - e->prefSize : e->prefSize - e->minSize;
-        e->sizeAtMinimum = e->prefSize + bandSize * minFactor;
-
-        bandSize = prefFactor > 0 ? e->maxSize - e->prefSize : e->prefSize - e->minSize;
-        e->sizeAtPreferred = e->prefSize + bandSize * prefFactor;
-
-        bandSize = maxFactor > 0 ? e->maxSize - e->prefSize : e->prefSize - e->minSize;
-        e->sizeAtMaximum = e->prefSize + bandSize * maxFactor;
-
-        const qreal lower = qMin(e->sizeAtPreferred, e->sizeAtMaximum);
-        const qreal upper = qMax(e->sizeAtPreferred, e->sizeAtMaximum);
-        const qreal edgeBoundedExpSize = qBound(lower, e->expSize, upper);
-        e->sizeAtExpanding = edgeBoundedExpSize + expFactor * (e->sizeAtMaximum - edgeBoundedExpSize);
+        e->sizeAtMinimum = interpolate(minFactor, e->minSize, e->prefSize, e->maxSize);
+        e->sizeAtPreferred = interpolate(prefFactor, e->minSize, e->prefSize, e->maxSize);
+        e->sizeAtMaximum = interpolate(maxFactor, e->minSize, e->prefSize, e->maxSize);
 
         e->updateChildrenSizes();
     }
 }
 
-void SequentialAnchorData::refreshSizeHints(qreal effectiveSpacing)
-{
-    refreshSizeHints_helper(effectiveSpacing);
-}
-
-void SequentialAnchorData::refreshSizeHints_helper(qreal effectiveSpacing,
-                                                   bool refreshChildren)
+void SequentialAnchorData::calculateSizeHints()
 {
     minSize = 0;
     prefSize = 0;
-    expSize = 0;
     maxSize = 0;
 
     for (int i = 0; i < m_edges.count(); ++i) {
         AnchorData *edge = m_edges.at(i);
-
-        // If it's the case refresh children information first
-        if (refreshChildren)
-            edge->refreshSizeHints(effectiveSpacing);
-
         minSize += edge->minSize;
         prefSize += edge->prefSize;
-        expSize += edge->expSize;
         maxSize += edge->maxSize;
     }
 
     // See comment in AnchorData::refreshSizeHints() about sizeAt* values
     sizeAtMinimum = prefSize;
     sizeAtPreferred = prefSize;
-    sizeAtExpanding = prefSize;
     sizeAtMaximum = prefSize;
 }
 
@@ -429,18 +496,20 @@ QString GraphPath::toString() const
 #endif
 
 QGraphicsAnchorLayoutPrivate::QGraphicsAnchorLayoutPrivate()
-    : calculateGraphCacheDirty(1)
+    : calculateGraphCacheDirty(true), styleInfoDirty(true)
 {
     for (int i = 0; i < NOrientations; ++i) {
         for (int j = 0; j < 3; ++j) {
             sizeHints[i][j] = -1;
         }
-        sizeAtExpanding[i] = -1;
         interpolationProgress[i] = -1;
 
         spacings[i] = -1;
-        graphSimplified[i] = false;
         graphHasConflicts[i] = false;
+
+        layoutFirstVertex[i] = 0;
+        layoutCentralVertex[i] = 0;
+        layoutLastVertex[i] = 0;
     }
 }
 
@@ -481,67 +550,125 @@ inline static qreal checkAdd(qreal a, qreal b)
 }
 
 /*!
- * \internal
- *
- * Takes the sequence of vertices described by (\a before, \a vertices, \a after) and replaces
- * all anchors connected to the vertices in \a vertices with one simplified anchor between
- * \a before and \a after. The simplified anchor will be a placeholder for all the previous
- * anchors between \a before and \a after, and can be restored back to the anchors it is a
- * placeholder for.
- */
-static bool simplifySequentialChunk(Graph<AnchorVertex, AnchorData> *graph,
-                                    AnchorVertex *before,
-                                    const QVector<AnchorVertex*> &vertices,
-                                    AnchorVertex *after)
+    \internal
+
+    Adds \a newAnchor to the graph.
+
+    Returns the newAnchor itself if it could be added without further changes to the graph. If a
+    new parallel anchor had to be created, then returns the new parallel anchor. If a parallel anchor
+    had to be created and it results in an unfeasible setup, \a feasible is set to false, otherwise
+    true.
+
+    Note that in the case a new parallel anchor is created, it might also take over some constraints
+    from its children anchors.
+*/
+AnchorData *QGraphicsAnchorLayoutPrivate::addAnchorMaybeParallel(AnchorData *newAnchor, bool *feasible)
 {
-    int i;
+    Orientation orientation = Orientation(newAnchor->orientation);
+    Graph<AnchorVertex, AnchorData> &g = graph[orientation];
+    *feasible = true;
+
+    // If already exists one anchor where newAnchor is supposed to be, we create a parallel
+    // anchor.
+    if (AnchorData *oldAnchor = g.takeEdge(newAnchor->from, newAnchor->to)) {
+        ParallelAnchorData *parallel = new ParallelAnchorData(oldAnchor, newAnchor);
+
+        // The parallel anchor will "replace" its children anchors in
+        // every center constraint that they appear.
+
+        // ### If the dependent (center) anchors had reference(s) to their constraints, we
+        // could avoid traversing all the itemCenterConstraints.
+        QList<QSimplexConstraint *> &constraints = itemCenterConstraints[orientation];
+
+        AnchorData *children[2] = { oldAnchor, newAnchor };
+        QList<QSimplexConstraint *> *childrenConstraints[2] = { &parallel->m_firstConstraints,
+                                                                &parallel->m_secondConstraints };
+
+        for (int i = 0; i < 2; ++i) {
+            AnchorData *child = children[i];
+            QList<QSimplexConstraint *> *childConstraints = childrenConstraints[i];
+
+            if (!child->isCenterAnchor)
+                continue;
+
+            parallel->isCenterAnchor = true;
+
+            for (int i = 0; i < constraints.count(); ++i) {
+                QSimplexConstraint *c = constraints[i];
+                if (c->variables.contains(child)) {
+                    childConstraints->append(c);
+                    qreal v = c->variables.take(child);
+                    c->variables.insert(parallel, v);
+                }
+            }
+        }
+
+        // At this point we can identify that the parallel anchor is not feasible, e.g. one
+        // anchor minimum size is bigger than the other anchor maximum size.
+        *feasible = parallel->calculateSizeHints();
+        newAnchor = parallel;
+    }
+
+    g.createEdge(newAnchor->from, newAnchor->to, newAnchor);
+    return newAnchor;
+}
+
+/*!
+    \internal
+
+    Takes the sequence of vertices described by (\a before, \a vertices, \a after) and removes
+    all anchors connected to the vertices in \a vertices, returning one simplified anchor between
+    \a before and \a after.
+
+    Note that this function doesn't add the created anchor to the graph. This should be done by
+    the caller.
+*/
+static AnchorData *createSequence(Graph<AnchorVertex, AnchorData> *graph,
+                                  AnchorVertex *before,
+                                  const QVector<AnchorVertex*> &vertices,
+                                  AnchorVertex *after)
+{
+    AnchorData *data = graph->edgeData(before, vertices.first());
+    Q_ASSERT(data);
+
+    const bool forward = (before == data->from);
+    QVector<AnchorVertex *> orderedVertices;
+
+    if (forward) {
+        orderedVertices = vertices;
+    } else {
+        qSwap(before, after);
+        for (int i = vertices.count() - 1; i >= 0; --i)
+            orderedVertices.append(vertices.at(i));
+    }
+
 #if defined(QT_DEBUG) && 0
     QString strVertices;
-    for (i = 0; i < vertices.count(); ++i)
-        strVertices += QString::fromAscii("%1 - ").arg(vertices.at(i)->toString());
+    for (int i = 0; i < orderedVertices.count(); ++i) {
+        strVertices += QString::fromAscii("%1 - ").arg(orderedVertices.at(i)->toString());
+    }
     QString strPath = QString::fromAscii("%1 - %2%3").arg(before->toString(), strVertices, after->toString());
     qDebug("simplifying [%s] to [%s - %s]", qPrintable(strPath), qPrintable(before->toString()), qPrintable(after->toString()));
 #endif
 
-    SequentialAnchorData *sequence = new SequentialAnchorData;
     AnchorVertex *prev = before;
-    AnchorData *data;
-    for (i = 0; i <= vertices.count(); ++i) {
-        AnchorVertex *next = (i < vertices.count()) ? vertices.at(i) : after;
-        data = graph->takeEdge(prev, next);
-        sequence->m_edges.append(data);
+    QVector<AnchorData *> edges;
+
+    for (int i = 0; i <= orderedVertices.count(); ++i) {
+        AnchorVertex *next = (i < orderedVertices.count()) ? orderedVertices.at(i) : after;
+        AnchorData *ad = graph->takeEdge(prev, next);
+        Q_ASSERT(ad);
+        edges.append(ad);
         prev = next;
     }
-    sequence->setVertices(vertices);
+
+    SequentialAnchorData *sequence = new SequentialAnchorData(orderedVertices, edges);
     sequence->from = before;
     sequence->to = after;
 
-    sequence->refreshSizeHints_helper(0, false);
-
-    // data here is the last edge in the sequence
-    // ### this seems to be here for supporting reverse order sequences,
-    // but doesnt seem to be used right now
-    if (data->from != vertices.last())
-        qSwap(sequence->from, sequence->to);
-
-    // Note that since layout 'edges' can't be simplified away from
-    // the graph, it's safe to assume that if there's a layout
-    // 'edge', it'll be in the boundaries of the sequence.
-    sequence->isLayoutAnchor = (sequence->m_edges.first()->isLayoutAnchor
-                                || sequence->m_edges.last()->isLayoutAnchor);
-
-    AnchorData *newAnchor = sequence;
-    if (AnchorData *oldAnchor = graph->takeEdge(before, after)) {
-        ParallelAnchorData *parallel = new ParallelAnchorData(oldAnchor, sequence);
-        parallel->isLayoutAnchor = (oldAnchor->isLayoutAnchor
-                                     || sequence->isLayoutAnchor);
-        parallel->refreshSizeHints_helper(0, false);
-        newAnchor = parallel;
-    }
-    graph->createEdge(before, after, newAnchor);
+    sequence->calculateSizeHints();
 
-    // True if we created a parallel anchor
-    return newAnchor != sequence;
+    return sequence;
 }
 
 /*!
@@ -578,271 +705,546 @@ static bool simplifySequentialChunk(Graph<AnchorVertex, AnchorData> *graph,
    2. Go to (1)
    3. Done
 
-
-   * Gathering sequential anchors *
-   The algorithm walks the graph in depth-first order, and only collects vertices that has two
-   edges connected to it. If the vertex does not have two edges or if it is a layout edge,
-   it will take all the previously collected vertices and try to create a simplified sequential
-   anchor representing all the previously collected vertices.
-   Once the simplified anchor is inserted, the collected list is cleared in order to find the next
-   sequence to simplify.
-   Note that there are some catches to this that are not covered by the above explanation.
+   When creating the parallel anchors, the algorithm might identify unfeasible situations. In this
+   case the simplification process stops and returns false. Otherwise returns true.
 */
-void QGraphicsAnchorLayoutPrivate::simplifyGraph(Orientation orientation)
+bool QGraphicsAnchorLayoutPrivate::simplifyGraph(Orientation orientation)
 {
-    static bool noSimplification = !qgetenv("QT_ANCHORLAYOUT_NO_SIMPLIFICATION").isEmpty();
-    if (noSimplification || items.isEmpty())
-        return;
+    if (items.isEmpty())
+        return true;
 
-    if (graphSimplified[orientation])
-        return;
-    graphSimplified[orientation] = true;
-
-#if 0
+#if defined(QT_DEBUG) && 0
     qDebug("Simplifying Graph for %s",
            orientation == Horizontal ? "Horizontal" : "Vertical");
-#endif
 
-    AnchorVertex *rootVertex = graph[orientation].rootVertex();
+    static int count = 0;
+    if (orientation == Horizontal) {
+        count++;
+        dumpGraph(QString::fromAscii("%1-full").arg(count));
+    }
+#endif
 
-    if (!rootVertex)
-        return;
+    // Vertex simplification
+    if (!simplifyVertices(orientation)) {
+        restoreVertices(orientation);
+        return false;
+    }
 
+    // Anchor simplification
     bool dirty;
+    bool feasible = true;
     do {
-        dirty = simplifyGraphIteration(orientation);
-    } while (dirty);
+        dirty = simplifyGraphIteration(orientation, &feasible);
+    } while (dirty && feasible);
+
+    // Note that if we are not feasible, we fallback and make sure that the graph is fully restored
+    if (!feasible) {
+        restoreSimplifiedGraph(orientation);
+        restoreVertices(orientation);
+        return false;
+    }
+
+#if defined(QT_DEBUG) && 0
+    dumpGraph(QString::fromAscii("%1-simplified-%2").arg(count).arg(
+                  QString::fromAscii(orientation == Horizontal ? "Horizontal" : "Vertical")));
+#endif
+
+    return true;
+}
+
+static AnchorVertex *replaceVertex_helper(AnchorData *data, AnchorVertex *oldV, AnchorVertex *newV)
+{
+    AnchorVertex *other;
+    if (data->from == oldV) {
+        data->from = newV;
+        other = data->to;
+    } else {
+        data->to = newV;
+        other = data->from;
+    }
+    return other;
 }
 
-bool QGraphicsAnchorLayoutPrivate::simplifyGraphIteration(QGraphicsAnchorLayoutPrivate::Orientation orientation)
+bool QGraphicsAnchorLayoutPrivate::replaceVertex(Orientation orientation, AnchorVertex *oldV,
+                                                 AnchorVertex *newV, const QList<AnchorData *> &edges)
+{
+    Graph<AnchorVertex, AnchorData> &g = graph[orientation];
+    bool feasible = true;
+
+    for (int i = 0; i < edges.count(); ++i) {
+        AnchorData *ad = edges[i];
+        AnchorVertex *otherV = replaceVertex_helper(ad, oldV, newV);
+
+#if defined(QT_DEBUG)
+        ad->name = QString::fromAscii("%1 --to--> %2").arg(ad->from->toString()).arg(ad->to->toString());
+#endif
+
+        bool newFeasible;
+        AnchorData *newAnchor = addAnchorMaybeParallel(ad, &newFeasible);
+        feasible &= newFeasible;
+
+        if (newAnchor != ad) {
+            // A parallel was created, we mark that in the list of anchors created by vertex
+            // simplification. This is needed because we want to restore them in a separate step
+            // from the restoration of anchor simplification.
+            anchorsFromSimplifiedVertices[orientation].append(newAnchor);
+        }
+
+        g.takeEdge(oldV, otherV);
+    }
+
+    return feasible;
+}
+
+/*!
+    \internal
+*/
+bool QGraphicsAnchorLayoutPrivate::simplifyVertices(Orientation orientation)
 {
     Q_Q(QGraphicsAnchorLayout);
     Graph<AnchorVertex, AnchorData> &g = graph[orientation];
-    AnchorVertex *v = g.rootVertex();
 
-    QSet<AnchorVertex *> visited;
+    // We'll walk through vertices
     QStack<AnchorVertex *> stack;
-    stack.push(v);
-    QVector<AnchorVertex*> candidates;
+    stack.push(layoutFirstVertex[orientation]);
+    QSet<AnchorVertex *> visited;
 
-    const Qt::AnchorPoint centerEdge = pickEdge(Qt::AnchorHorizontalCenter, orientation);
-    const Qt::AnchorPoint layoutEdge = oppositeEdge(v->m_edge);
+    while (!stack.isEmpty()) {
+        AnchorVertex *v = stack.pop();
+        visited.insert(v);
+
+        // Each adjacent of 'v' is a possible vertex to be merged. So we traverse all of
+        // them. Since once a merge is made, we might add new adjacents, and we don't want to
+        // pass two times through one adjacent. The 'index' is used to track our position.
+        QList<AnchorVertex *> adjacents = g.adjacentVertices(v);
+        int index = 0;
+
+        while (index < adjacents.count()) {
+            AnchorVertex *next = adjacents.at(index);
+            index++;
+
+            AnchorData *data = g.edgeData(v, next);
+            const bool bothLayoutVertices = v->m_item == q && next->m_item == q;
+            const bool zeroSized = !data->minSize && !data->maxSize;
+
+            if (!bothLayoutVertices && zeroSized) {
+
+                // Create a new vertex pair, note that we keep a list of those vertices so we can
+                // easily process them when restoring the graph.
+                AnchorVertexPair *newV = new AnchorVertexPair(v, next, data);
+                simplifiedVertices[orientation].append(newV);
+
+                // Collect the anchors of both vertices, the new vertex pair will take their place
+                // in those anchors
+                const QList<AnchorVertex *> &vAdjacents = g.adjacentVertices(v);
+                const QList<AnchorVertex *> &nextAdjacents = g.adjacentVertices(next);
+
+                for (int i = 0; i < vAdjacents.count(); ++i) {
+                    AnchorVertex *adjacent = vAdjacents.at(i);
+                    if (adjacent != next) {
+                        AnchorData *ad = g.edgeData(v, adjacent);
+                        newV->m_firstAnchors.append(ad);
+                    }
+                }
 
-    bool dirty = false;
+                for (int i = 0; i < nextAdjacents.count(); ++i) {
+                    AnchorVertex *adjacent = nextAdjacents.at(i);
+                    if (adjacent != v) {
+                        AnchorData *ad = g.edgeData(next, adjacent);
+                        newV->m_secondAnchors.append(ad);
 
-    // walk depth-first.
-    while (!stack.isEmpty()) {
-        v = stack.pop();
-        QList<AnchorVertex *> vertices = g.adjacentVertices(v);
-        const int count = vertices.count();
-        bool endOfSequence = (v->m_item == q && v->m_edge == layoutEdge) || count != 2;
-        if (count == 2 && v->m_item != q) {
-            candidates.append(v);
-            if (visited.contains(vertices.first()) && visited.contains(vertices.last())) {
-                // in case of a cycle
-                endOfSequence = true;
+                        // We'll also add new vertices to the adjacent list of the new 'v', to be
+                        // created as a vertex pair and replace the current one.
+                        if (!adjacents.contains(adjacent))
+                            adjacents.append(adjacent);
+                    }
+                }
+
+                // ### merge this loop into the ones that calculated m_firstAnchors/m_secondAnchors?
+                // Make newV take the place of v and next
+                bool feasible = replaceVertex(orientation, v, newV, newV->m_firstAnchors);
+                feasible &= replaceVertex(orientation, next, newV, newV->m_secondAnchors);
+
+                // Update the layout vertex information if one of the vertices is a layout vertex.
+                AnchorVertex *layoutVertex = 0;
+                if (v->m_item == q)
+                    layoutVertex = v;
+                else if (next->m_item == q)
+                    layoutVertex = next;
+
+                if (layoutVertex) {
+                    // Layout vertices always have m_item == q...
+                    newV->m_item = q;
+                    changeLayoutVertex(orientation, layoutVertex, newV);
+                }
+
+                g.takeEdge(v, next);
+
+                // If a non-feasibility is found, we leave early and cancel the simplification
+                if (!feasible)
+                    return false;
+
+                v = newV;
+                visited.insert(newV);
+
+            } else if (!visited.contains(next) && !stack.contains(next)) {
+                // If the adjacent is not fit for merge and it wasn't visited by the outermost
+                // loop, we add it to the stack.
+                stack.push(next);
             }
         }
-        if (endOfSequence && candidates.count() >= 1) {
-            int i;
-            AnchorVertex *afterSequence= 0;
-            AnchorVertex *beforeSequence = 0;
-            // find the items before and after the valid sequence
-            if (candidates.count() == 1) {
-                QList<AnchorVertex *> beforeAndAfterVertices = g.adjacentVertices(candidates.at(0));
-                Q_ASSERT(beforeAndAfterVertices.count() == 2);
-                // Since we only have one vertex, we can pick
-                // any of the two vertices to become before/after.
-                afterSequence = beforeAndAfterVertices.last();
-                beforeSequence = beforeAndAfterVertices.first();
-            } else {
-                QList<AnchorVertex *> adjacentOfSecondLastVertex = g.adjacentVertices(candidates.last());
-                Q_ASSERT(adjacentOfSecondLastVertex.count() == 2);
-                if (adjacentOfSecondLastVertex.first() == candidates.at(candidates.count() - 2))
-                    afterSequence = adjacentOfSecondLastVertex.last();
-                else
-                    afterSequence = adjacentOfSecondLastVertex.first();
+    }
 
-                QList<AnchorVertex *> adjacentOfSecondVertex = g.adjacentVertices(candidates.first());
-                Q_ASSERT(adjacentOfSecondVertex.count() == 2);
-                if (adjacentOfSecondVertex.first() == candidates.at(1))
-                    beforeSequence = adjacentOfSecondVertex.last();
-                else
-                    beforeSequence = adjacentOfSecondVertex.first();
-            }
-            // The complete path of the sequence to simplify is: beforeSequence, <candidates>, afterSequence
-            // where beforeSequence and afterSequence are the endpoints where the anchor is inserted
-            // between.
-#if defined(QT_DEBUG) && 0
-            // ### DEBUG
-            QString strCandidates;
-            for (i = 0; i < candidates.count(); ++i)
-                strCandidates += QString::fromAscii("%1 - ").arg(candidates.at(i)->toString());
-            QString strPath = QString::fromAscii("%1 - %2%3").arg(beforeSequence->toString(), strCandidates, afterSequence->toString());
-            qDebug("candidate list for sequential simplification:\n[%s]", qPrintable(strPath));
-#endif
+    return true;
+}
+
+/*!
+    \internal
+
+    One iteration of the simplification algorithm. Returns true if another iteration is needed.
+
+    The algorithm walks the graph in depth-first order, and only collects vertices that has two
+    edges connected to it.  If the vertex does not have two edges or if it is a layout edge, it
+    will take all the previously collected vertices and try to create a simplified sequential
+    anchor representing all the previously collected vertices.  Once the simplified anchor is
+    inserted, the collected list is cleared in order to find the next sequence to simplify.
 
-            bool forward = true;
-            AnchorVertex *prev = beforeSequence;
-            int intervalFrom = 0;
+    Note that there are some catches to this that are not covered by the above explanation, see
+    the function comments for more details.
+*/
+bool QGraphicsAnchorLayoutPrivate::simplifyGraphIteration(QGraphicsAnchorLayoutPrivate::Orientation orientation,
+                                                          bool *feasible)
+{
+    Q_Q(QGraphicsAnchorLayout);
+    Graph<AnchorVertex, AnchorData> &g = graph[orientation];
 
-            // Check for directionality (from). We don't want to destroy that information,
-            // thus we only combine anchors with the same direction.
+    QSet<AnchorVertex *> visited;
+    QStack<QPair<AnchorVertex *, AnchorVertex *> > stack;
+    stack.push(qMakePair(static_cast<AnchorVertex *>(0), layoutFirstVertex[orientation]));
+    QVector<AnchorVertex*> candidates;
+    bool candidatesForward = true;
 
-            // "i" is the index *including* the beforeSequence and afterSequence vertices.
-            for (i = 1; i <= candidates.count() + 1; ++i) {
-                bool atVertexAfter = i > candidates.count();
-                AnchorVertex *v1 = atVertexAfter ? afterSequence : candidates.at(i - 1);
-                AnchorData *data = g.edgeData(prev, v1);
+    // Walk depth-first, in the stack we store start of the candidate sequence (beforeSequence)
+    // and the vertex to be visited.
+    while (!stack.isEmpty()) {
+        QPair<AnchorVertex *, AnchorVertex *> pair = stack.pop();
+        AnchorVertex *beforeSequence = pair.first;
+        AnchorVertex *v = pair.second;
+
+        // The basic idea is to determine whether we found an end of sequence,
+        // if that's the case, we stop adding vertices to the candidate list
+        // and do a simplification step.
+        //
+        // A vertex can trigger an end of sequence if
+        // (a) it is a layout vertex, we don't simplify away the layout vertices;
+        // (b) it does not have exactly 2 adjacents;
+        // (c) it will change the direction of the sequence;
+        // (d) its next adjacent is already visited (a cycle in the graph);
+        // (e) the next anchor is a center anchor.
+
+        const QList<AnchorVertex *> &adjacents = g.adjacentVertices(v);
+        const bool isLayoutVertex = v->m_item == q;
+        AnchorVertex *afterSequence = v;
+        bool endOfSequence = false;
+
+        //
+        // Identify the end cases.
+        //
+
+        // Identifies cases (a) and (b)
+        endOfSequence = isLayoutVertex || adjacents.count() != 2;
+
+        if (!endOfSequence) {
+            // If this is the first vertice, determine what is the direction to use for this
+            // sequence.
+            if (candidates.isEmpty()) {
+                const AnchorData *data = g.edgeData(beforeSequence, v);
                 Q_ASSERT(data);
-                if (i == 1) {
-                    forward = (prev == data->from ? true : false);
-                } else if (forward != (prev == data->from) || atVertexAfter) {
-                    int intervalTo = i;
-                    if (forward != (prev == data->from))
-                        --intervalTo;
-
-                    // intervalFrom and intervalTo should now be indices to the vertex before and
-                    // after the sequential anchor.
-                    if (intervalTo - intervalFrom >= 2) {
-                        // simplify in the range [intervalFrom, intervalTo]
-
-                        // Trim off internal center anchors (Left-Center/Center-Right) from the
-                        // start and the end of the sequence. We never want to simplify internal
-                        // center anchors where there is an external anchor connected to the center.
-                        AnchorVertex *intervalVertexFrom = intervalFrom == 0 ? beforeSequence : candidates.at(intervalFrom - 1);
-                        int effectiveIntervalFrom = intervalFrom;
-                        if (intervalVertexFrom->m_edge == centerEdge
-                            && intervalVertexFrom->m_item == candidates.at(effectiveIntervalFrom)->m_item) {
-                            ++effectiveIntervalFrom;
-                            intervalVertexFrom = candidates.at(effectiveIntervalFrom - 1);
-                        }
-                        AnchorVertex *intervalVertexTo = intervalTo <= candidates.count() ? candidates.at(intervalTo - 1) : afterSequence;
-                        int effectiveIntervalTo = intervalTo;
-                        if (intervalVertexTo->m_edge == centerEdge
-                            && intervalVertexTo->m_item == candidates.at(effectiveIntervalTo - 2)->m_item) {
-                            --effectiveIntervalTo;
-                            intervalVertexTo = candidates.at(effectiveIntervalTo - 1);
-                        }
-                        if (effectiveIntervalTo - effectiveIntervalFrom >= 2) {
-                            QVector<AnchorVertex*> subCandidates;
-                            if (forward) {
-                               subCandidates = candidates.mid(effectiveIntervalFrom, effectiveIntervalTo - effectiveIntervalFrom - 1);
-                            } else {
-                                // reverse the order of the candidates.
-                                qSwap(intervalVertexFrom, intervalVertexTo);
-                                do {
-                                    ++effectiveIntervalFrom;
-                                    subCandidates.prepend(candidates.at(effectiveIntervalFrom - 1));
-                                } while (effectiveIntervalFrom < effectiveIntervalTo - 1);
-                            }
-                            if (simplifySequentialChunk(&g, intervalVertexFrom, subCandidates, intervalVertexTo)) {
-                                dirty = true;
-                                break;
-                            }
-                            // finished simplification of chunk with same direction
-                        }
-                    }
-                    if (forward == (prev == data->from))
-                        --intervalTo;
-                    intervalFrom = intervalTo;
+                candidatesForward = (beforeSequence == data->from);
+            }
 
-                    forward = !forward;
+            // This is a tricky part. We peek at the next vertex to find out whether
+            //
+            // - the edge from this vertex to the next vertex has the same direction;
+            // - we already visited the next vertex;
+            // - the next anchor is a center.
+            //
+            // Those are needed to identify the remaining end of sequence cases. Note that unlike
+            // (a) and (b), we preempt the end of sequence by looking into the next vertex.
+
+            // Peek at the next vertex
+            AnchorVertex *after;
+            if (candidates.isEmpty())
+                after = (beforeSequence == adjacents.last() ? adjacents.first() : adjacents.last());
+            else
+                after = (candidates.last() == adjacents.last() ? adjacents.first() : adjacents.last());
+
+            // ### At this point we assumed that candidates will not contain 'after', this may not hold
+            // when simplifying FLOATing anchors.
+            Q_ASSERT(!candidates.contains(after));
+
+            const AnchorData *data = g.edgeData(v, after);
+            Q_ASSERT(data);
+            const bool willChangeDirection = (candidatesForward != (v == data->from));
+            const bool cycleFound = visited.contains(after);
+
+            // Now cases (c), (d) and (e)...
+            endOfSequence = willChangeDirection || cycleFound || data->isCenterAnchor;
+
+            if (endOfSequence) {
+                if (!willChangeDirection) {
+                    // If the direction will not change, we can add the current vertex to the
+                    // candidates list and we know that 'after' can be used as afterSequence.
+                    candidates.append(v);
+                    afterSequence = after;
                 }
-                prev = v1;
+            } else {
+                // If it's not an end of sequence, then the vertex didn't trigger neither of the
+                // previously four cases, so it can be added to the candidates list.
+                candidates.append(v);
             }
+        }
+
+        //
+        // Add next non-visited vertices to the stack.
+        //
+        for (int i = 0; i < adjacents.count(); ++i) {
+            AnchorVertex *next = adjacents.at(i);
+            if (visited.contains(next))
+                continue;
 
-            if (dirty)
-                break;
+            // If current vertex is an end of sequence, and it'll reset the candidates list. So
+            // the next vertices will build candidates lists with the current vertex as 'before'
+            // vertex. If it's not an end of sequence, we keep the original 'before' vertex,
+            // since we are keeping the candidates list.
+            if (endOfSequence)
+                stack.push(qMakePair(v, next));
+            else
+                stack.push(qMakePair(beforeSequence, next));
         }
 
-        if (endOfSequence)
-            candidates.clear();
+        visited.insert(v);
+
+        if (!endOfSequence || candidates.isEmpty())
+            continue;
+
+        //
+        // Create a sequence for (beforeSequence, candidates, afterSequence).
+        //
+
+        // One restriction we have is to not simplify half of an anchor and let the other half
+        // unsimplified. So we remove center edges before and after the sequence.
+        const AnchorData *firstAnchor = g.edgeData(beforeSequence, candidates.first());
+        if (firstAnchor->isCenterAnchor) {
+            beforeSequence = candidates.first();
+            candidates.remove(0);
 
-        for (int i = 0; i < count; ++i) {
-            AnchorVertex *next = vertices.at(i);
-            if (next->m_item == q && next->m_edge == centerEdge)
+            // If there's not candidates to be simplified, leave.
+            if (candidates.isEmpty())
                 continue;
-            if (visited.contains(next))
+        }
+
+        const AnchorData *lastAnchor = g.edgeData(candidates.last(), afterSequence);
+        if (lastAnchor->isCenterAnchor) {
+            afterSequence = candidates.last();
+            candidates.remove(candidates.count() - 1);
+
+            if (candidates.isEmpty())
                 continue;
-            stack.push(next);
         }
 
-        visited.insert(v);
+        //
+        // Add the sequence to the graph.
+        //
+
+        AnchorData *sequence = createSequence(&g, beforeSequence, candidates, afterSequence);
+
+        // If 'beforeSequence' and 'afterSequence' already had an anchor between them, we'll
+        // create a parallel anchor between the new sequence and the old anchor.
+        bool newFeasible;
+        AnchorData *newAnchor = addAnchorMaybeParallel(sequence, &newFeasible);
+
+        if (!newFeasible) {
+            *feasible = false;
+            return false;
+        }
+
+        // When a new parallel anchor is create in the graph, we finish the iteration and return
+        // true to indicate a new iteration is needed. This happens because a parallel anchor
+        // changes the number of adjacents one vertex has, possibly opening up oportunities for
+        // building candidate lists (when adjacents == 2).
+        if (newAnchor != sequence)
+            return true;
+
+        // If there was no parallel simplification, we'll keep walking the graph. So we clear the
+        // candidates list to start again.
+        candidates.clear();
     }
 
-    return dirty;
+    return false;
 }
 
-static void restoreSimplifiedAnchor(Graph<AnchorVertex, AnchorData> &g,
-                                    AnchorData *edge,
-                                    AnchorVertex *before,
-                                    AnchorVertex *after)
+void QGraphicsAnchorLayoutPrivate::restoreSimplifiedAnchor(AnchorData *edge)
 {
-    Q_ASSERT(edge->type != AnchorData::Normal);
 #if 0
     static const char *anchortypes[] = {"Normal",
                                         "Sequential",
                                         "Parallel"};
     qDebug("Restoring %s edge.", anchortypes[int(edge->type)]);
 #endif
-    if (edge->type == AnchorData::Sequential) {
-        SequentialAnchorData* seqEdge = static_cast<SequentialAnchorData*>(edge);
-        // restore the sequential anchor
-        AnchorVertex *prev = before;
-        AnchorVertex *last = after;
-        if (edge->from != prev)
-            qSwap(last, prev);
-
-        for (int i = 0; i < seqEdge->m_edges.count(); ++i) {
-            AnchorVertex *v1 = (i < seqEdge->m_children.count()) ? seqEdge->m_children.at(i) : last;
-            AnchorData *data = seqEdge->m_edges.at(i);
-            if (data->type != AnchorData::Normal) {
-                restoreSimplifiedAnchor(g, data, prev, v1);
-            } else {
-                g.createEdge(prev, v1, data);
-            }
-            prev = v1;
+
+    Graph<AnchorVertex, AnchorData> &g = graph[edge->orientation];
+
+    if (edge->type == AnchorData::Normal) {
+        g.createEdge(edge->from, edge->to, edge);
+
+    } else if (edge->type == AnchorData::Sequential) {
+        SequentialAnchorData *sequence = static_cast<SequentialAnchorData *>(edge);
+
+        for (int i = 0; i < sequence->m_edges.count(); ++i) {
+            AnchorData *data = sequence->m_edges.at(i);
+            restoreSimplifiedAnchor(data);
         }
+
+        delete sequence;
+
     } else if (edge->type == AnchorData::Parallel) {
-        ParallelAnchorData* parallelEdge = static_cast<ParallelAnchorData*>(edge);
-        AnchorData *parallelEdges[2] = {parallelEdge->firstEdge,
-                                        parallelEdge->secondEdge};
-        for (int i = 0; i < 2; ++i) {
-            AnchorData *data = parallelEdges[i];
-            if (data->type == AnchorData::Normal) {
-                g.createEdge(before, after, data);
-            } else {
-                restoreSimplifiedAnchor(g, data, before, after);
-            }
-        }
+
+        // Skip parallel anchors that were created by vertex simplification, they will be processed
+        // later, when restoring vertex simplification.
+        // ### we could improve this check bit having a bit inside 'edge'
+        if (anchorsFromSimplifiedVertices[edge->orientation].contains(edge))
+            return;
+
+        ParallelAnchorData* parallel = static_cast<ParallelAnchorData*>(edge);
+        restoreSimplifiedConstraints(parallel);
+
+        // ### Because of the way parallel anchors are created in the anchor simplification
+        // algorithm, we know that one of these will be a sequence, so it'll be safe if the other
+        // anchor create an edge between the same vertices as the parallel.
+        Q_ASSERT(parallel->firstEdge->type == AnchorData::Sequential
+                 || parallel->secondEdge->type == AnchorData::Sequential);
+        restoreSimplifiedAnchor(parallel->firstEdge);
+        restoreSimplifiedAnchor(parallel->secondEdge);
+
+        delete parallel;
     }
 }
 
-void QGraphicsAnchorLayoutPrivate::restoreSimplifiedGraph(Orientation orientation)
+void QGraphicsAnchorLayoutPrivate::restoreSimplifiedConstraints(ParallelAnchorData *parallel)
 {
-    if (!graphSimplified[orientation])
+    if (!parallel->isCenterAnchor)
         return;
-    graphSimplified[orientation] = false;
 
+    for (int i = 0; i < parallel->m_firstConstraints.count(); ++i) {
+        QSimplexConstraint *c = parallel->m_firstConstraints.at(i);
+        qreal v = c->variables[parallel];
+        c->variables.remove(parallel);
+        c->variables.insert(parallel->firstEdge, v);
+    }
+
+    for (int i = 0; i < parallel->m_secondConstraints.count(); ++i) {
+        QSimplexConstraint *c = parallel->m_secondConstraints.at(i);
+        qreal v = c->variables[parallel];
+        c->variables.remove(parallel);
+        c->variables.insert(parallel->secondEdge, v);
+    }
+}
+
+void QGraphicsAnchorLayoutPrivate::restoreSimplifiedGraph(Orientation orientation)
+{
 #if 0
     qDebug("Restoring Simplified Graph for %s",
            orientation == Horizontal ? "Horizontal" : "Vertical");
 #endif
 
+    // Restore anchor simplification
     Graph<AnchorVertex, AnchorData> &g = graph[orientation];
-
     QList<QPair<AnchorVertex*, AnchorVertex*> > connections = g.connections();
     for (int i = 0; i < connections.count(); ++i) {
         AnchorVertex *v1 = connections.at(i).first;
         AnchorVertex *v2 = connections.at(i).second;
         AnchorData *edge = g.edgeData(v1, v2);
-        if (edge->type != AnchorData::Normal) {
-            AnchorData *oldEdge = g.takeEdge(v1, v2);
-            restoreSimplifiedAnchor(g, edge, v1, v2);
-            delete oldEdge;
+
+        // We restore only sequential anchors and parallels that were not created by
+        // vertex simplification.
+        if (edge->type == AnchorData::Sequential
+            || (edge->type == AnchorData::Parallel &&
+                !anchorsFromSimplifiedVertices[orientation].contains(edge))) {
+
+            g.takeEdge(v1, v2);
+            restoreSimplifiedAnchor(edge);
+        }
+    }
+
+    restoreVertices(orientation);
+}
+
+void QGraphicsAnchorLayoutPrivate::restoreVertices(Orientation orientation)
+{
+    Q_Q(QGraphicsAnchorLayout);
+
+    Graph<AnchorVertex, AnchorData> &g = graph[orientation];
+    QList<AnchorVertexPair *> &toRestore = simplifiedVertices[orientation];
+
+    // We will restore the vertices in the inverse order of creation, this way we ensure that
+    // the vertex being restored was not wrapped by another simplification.
+    for (int i = toRestore.count() - 1; i >= 0; --i) {
+        AnchorVertexPair *pair = toRestore.at(i);
+        QList<AnchorVertex *> adjacents = g.adjacentVertices(pair);
+
+        // Restore the removed edge, this will also restore both vertices 'first' and 'second' to
+        // the graph structure.
+        AnchorVertex *first = pair->m_first;
+        AnchorVertex *second = pair->m_second;
+        g.createEdge(first, second, pair->m_removedAnchor);
+
+        // Restore the anchors for the first child vertex
+        for (int j = 0; j < pair->m_firstAnchors.count(); ++j) {
+            AnchorData *ad = pair->m_firstAnchors.at(j);
+            Q_ASSERT(ad->from == pair || ad->to == pair);
+
+            replaceVertex_helper(ad, pair, first);
+            g.createEdge(ad->from, ad->to, ad);
         }
+
+        // Restore the anchors for the second child vertex
+        for (int j = 0; j < pair->m_secondAnchors.count(); ++j) {
+            AnchorData *ad = pair->m_secondAnchors.at(j);
+            Q_ASSERT(ad->from == pair || ad->to == pair);
+
+            replaceVertex_helper(ad, pair, second);
+            g.createEdge(ad->from, ad->to, ad);
+        }
+
+        for (int j = 0; j < adjacents.count(); ++j) {
+            g.takeEdge(pair, adjacents.at(j));
+        }
+
+        // The pair simplified a layout vertex, so place back the correct vertex in the variable
+        // that track layout vertices
+        if (pair->m_item == q) {
+            AnchorVertex *layoutVertex = first->m_item == q ? first : second;
+            Q_ASSERT(layoutVertex->m_item == q);
+            changeLayoutVertex(orientation, pair, layoutVertex);
+        }
+
+        delete pair;
     }
+    toRestore.clear();
+
+    // The restoration process for vertex simplification also restored the effect of the
+    // parallel anchors created during vertex simplification, so we just need to restore
+    // the constraints in case of parallels that contain center anchors. For the same
+    // reason as above, order matters here.
+    QList<AnchorData *> &parallelAnchors = anchorsFromSimplifiedVertices[orientation];
+
+    for (int i = parallelAnchors.count() - 1; i >= 0; --i) {
+        ParallelAnchorData *parallel = static_cast<ParallelAnchorData *>(parallelAnchors.at(i));
+        restoreSimplifiedConstraints(parallel);
+        delete parallel;
+    }
+    parallelAnchors.clear();
 }
 
 QGraphicsAnchorLayoutPrivate::Orientation
@@ -872,9 +1274,10 @@ void QGraphicsAnchorLayoutPrivate::createLayoutEdges()
     data->maxSize = QWIDGETSIZE_MAX;
     data->skipInPreferred = 1;
 
-    // Set the Layout Left edge as the root of the horizontal graph.
-    AnchorVertex *v = internalVertex(layout, Qt::AnchorLeft);
-    graph[Horizontal].setRootVertex(v);
+    // Save a reference to layout vertices
+    layoutFirstVertex[Horizontal] = internalVertex(layout, Qt::AnchorLeft);
+    layoutCentralVertex[Horizontal] = 0;
+    layoutLastVertex[Horizontal] = internalVertex(layout, Qt::AnchorRight);
 
     // Vertical
     data = new AnchorData;
@@ -883,17 +1286,18 @@ void QGraphicsAnchorLayoutPrivate::createLayoutEdges()
     data->maxSize = QWIDGETSIZE_MAX;
     data->skipInPreferred = 1;
 
-    // Set the Layout Top edge as the root of the vertical graph.
-    v = internalVertex(layout, Qt::AnchorTop);
-    graph[Vertical].setRootVertex(v);
+    // Save a reference to layout vertices
+    layoutFirstVertex[Vertical] = internalVertex(layout, Qt::AnchorTop);
+    layoutCentralVertex[Vertical] = 0;
+    layoutLastVertex[Vertical] = internalVertex(layout, Qt::AnchorBottom);
 }
 
 void QGraphicsAnchorLayoutPrivate::deleteLayoutEdges()
 {
     Q_Q(QGraphicsAnchorLayout);
 
-    Q_ASSERT(internalVertex(q, Qt::AnchorHorizontalCenter) == NULL);
-    Q_ASSERT(internalVertex(q, Qt::AnchorVerticalCenter) == NULL);
+    Q_ASSERT(!internalVertex(q, Qt::AnchorHorizontalCenter));
+    Q_ASSERT(!internalVertex(q, Qt::AnchorVerticalCenter));
 
     removeAnchor_helper(internalVertex(q, Qt::AnchorLeft),
                         internalVertex(q, Qt::AnchorRight));
@@ -903,19 +1307,17 @@ void QGraphicsAnchorLayoutPrivate::deleteLayoutEdges()
 
 void QGraphicsAnchorLayoutPrivate::createItemEdges(QGraphicsLayoutItem *item)
 {
-    Q_ASSERT(!graphSimplified[Horizontal] && !graphSimplified[Vertical]);
-
     items.append(item);
 
     // Create horizontal and vertical internal anchors for the item and
     // refresh its size hint / policy values.
     AnchorData *data = new AnchorData;
     addAnchor_helper(item, Qt::AnchorLeft, item, Qt::AnchorRight, data);
-    data->refreshSizeHints(0); // 0 = effectiveSpacing, will not be used
+    data->refreshSizeHints();
 
     data = new AnchorData;
     addAnchor_helper(item, Qt::AnchorTop, item, Qt::AnchorBottom, data);
-    data->refreshSizeHints(0); // 0 = effectiveSpacing, will not be used
+    data->refreshSizeHints();
 }
 
 /*!
@@ -932,6 +1334,8 @@ void QGraphicsAnchorLayoutPrivate::createItemEdges(QGraphicsLayoutItem *item)
 void QGraphicsAnchorLayoutPrivate::createCenterAnchors(
     QGraphicsLayoutItem *item, Qt::AnchorPoint centerEdge)
 {
+    Q_Q(QGraphicsAnchorLayout);
+
     Orientation orientation;
     switch (centerEdge) {
     case Qt::AnchorHorizontalCenter:
@@ -945,8 +1349,6 @@ void QGraphicsAnchorLayoutPrivate::createCenterAnchors(
         return;
     }
 
-    Q_ASSERT(!graphSimplified[orientation]);
-
     // Check if vertex already exists
     if (internalVertex(item, centerEdge))
         return;
@@ -973,23 +1375,33 @@ void QGraphicsAnchorLayoutPrivate::createCenterAnchors(
     AnchorData *data = new AnchorData;
     c->variables.insert(data, 1.0);
     addAnchor_helper(item, firstEdge, item, centerEdge, data);
-    data->refreshSizeHints(0);
+    data->isCenterAnchor = true;
+    data->dependency = AnchorData::Master;
+    data->refreshSizeHints();
 
     data = new AnchorData;
     c->variables.insert(data, -1.0);
     addAnchor_helper(item, centerEdge, item, lastEdge, data);
-    data->refreshSizeHints(0);
+    data->isCenterAnchor = true;
+    data->dependency = AnchorData::Slave;
+    data->refreshSizeHints();
 
     itemCenterConstraints[orientation].append(c);
 
     // Remove old one
     removeAnchor_helper(first, last);
+
+    if (item == q) {
+        layoutCentralVertex[orientation] = internalVertex(q, centerEdge);
+    }
 }
 
 void QGraphicsAnchorLayoutPrivate::removeCenterAnchors(
     QGraphicsLayoutItem *item, Qt::AnchorPoint centerEdge,
     bool substitute)
 {
+    Q_Q(QGraphicsAnchorLayout);
+
     Orientation orientation;
     switch (centerEdge) {
     case Qt::AnchorHorizontalCenter:
@@ -1003,8 +1415,6 @@ void QGraphicsAnchorLayoutPrivate::removeCenterAnchors(
         return;
     }
 
-    Q_ASSERT(!graphSimplified[orientation]);
-
     // Orientation code
     Qt::AnchorPoint firstEdge;
     Qt::AnchorPoint lastEdge;
@@ -1031,7 +1441,7 @@ void QGraphicsAnchorLayoutPrivate::removeCenterAnchors(
     AnchorData *oldData = g.edgeData(first, center);
     // Remove center constraint
     for (int i = itemCenterConstraints[orientation].count() - 1; i >= 0; --i) {
-        if (itemCenterConstraints[orientation][i]->variables.contains(oldData)) {
+        if (itemCenterConstraints[orientation].at(i)->variables.contains(oldData)) {
             delete itemCenterConstraints[orientation].takeAt(i);
             break;
         }
@@ -1041,7 +1451,7 @@ void QGraphicsAnchorLayoutPrivate::removeCenterAnchors(
         // Create the new anchor that should substitute the left-center-right anchors.
         AnchorData *data = new AnchorData;
         addAnchor_helper(item, firstEdge, item, lastEdge, data);
-        data->refreshSizeHints(0);
+        data->refreshSizeHints();
 
         // Remove old anchors
         removeAnchor_helper(first, center);
@@ -1062,14 +1472,16 @@ void QGraphicsAnchorLayoutPrivate::removeCenterAnchors(
         // by this time, the center vertex is deleted and merged into a non-centered internal anchor
         removeAnchor_helper(first, internalVertex(item, lastEdge));
     }
+
+    if (item == q) {
+        layoutCentralVertex[orientation] = 0;
+    }
 }
 
 
 void QGraphicsAnchorLayoutPrivate::removeCenterConstraints(QGraphicsLayoutItem *item,
                                                            Orientation orientation)
 {
-    Q_ASSERT(!graphSimplified[orientation]);
-
     // Remove the item center constraints associated to this item
     // ### This is a temporary solution. We should probably use a better
     // data structure to hold items and/or their associated constraints
@@ -1091,7 +1503,7 @@ void QGraphicsAnchorLayoutPrivate::removeCenterConstraints(QGraphicsLayoutItem *
 
     // Look for our anchor in all item center constraints, then remove it
     for (int i = 0; i < itemCenterConstraints[orientation].size(); ++i) {
-        if (itemCenterConstraints[orientation][i]->variables.contains(internalAnchor)) {
+        if (itemCenterConstraints[orientation].at(i)->variables.contains(internalAnchor)) {
             delete itemCenterConstraints[orientation].takeAt(i);
             break;
         }
@@ -1100,15 +1512,21 @@ void QGraphicsAnchorLayoutPrivate::removeCenterConstraints(QGraphicsLayoutItem *
 
 /*!
  * \internal
+ * Implements the high level "addAnchor" feature. Called by the public API
+ * addAnchor method.
+ *
+ * The optional \a spacing argument defines the size of the anchor. If not provided,
+ * the anchor size is either 0 or not-set, depending on type of anchor created (see
+ * matrix below).
  *
- * Helper function that is called from the anchor functions in the public API.
- * If \a spacing is 0, it will pick up the spacing defined by the style.
+ * All anchors that remain with size not-set will assume the standard spacing,
+ * set either by the layout style or through the "setSpacing" layout API.
  */
 QGraphicsAnchor *QGraphicsAnchorLayoutPrivate::addAnchor(QGraphicsLayoutItem *firstItem,
-                                                      Qt::AnchorPoint firstEdge,
-                                                      QGraphicsLayoutItem *secondItem,
-                                                      Qt::AnchorPoint secondEdge,
-                                                      qreal *spacing)
+                                                         Qt::AnchorPoint firstEdge,
+                                                         QGraphicsLayoutItem *secondItem,
+                                                         Qt::AnchorPoint secondEdge,
+                                                         qreal *spacing)
 {
     Q_Q(QGraphicsAnchorLayout);
     if ((firstItem == 0) || (secondItem == 0)) {
@@ -1129,10 +1547,6 @@ QGraphicsAnchor *QGraphicsAnchorLayoutPrivate::addAnchor(QGraphicsLayoutItem *fi
         return 0;
     }
 
-    // Guarantee that the graph is no simplified when adding this anchor,
-    // anchor manipulation always happen in the full graph
-    restoreSimplifiedGraph(edgeOrientation(firstEdge));
-
     // In QGraphicsAnchorLayout, items are represented in its internal
     // graph as four anchors that connect:
     //  - Left -> HCenter
@@ -1142,12 +1556,10 @@ QGraphicsAnchor *QGraphicsAnchorLayoutPrivate::addAnchor(QGraphicsLayoutItem *fi
 
     // Ensure that the internal anchors have been created for both items.
     if (firstItem != q && !items.contains(firstItem)) {
-        restoreSimplifiedGraph(edgeOrientation(firstEdge) == Horizontal ? Vertical : Horizontal);
         createItemEdges(firstItem);
         addChildLayoutItem(firstItem);
     }
     if (secondItem != q && !items.contains(secondItem)) {
-        restoreSimplifiedGraph(edgeOrientation(firstEdge) == Horizontal ? Vertical : Horizontal);
         createItemEdges(secondItem);
         addChildLayoutItem(secondItem);
     }
@@ -1160,7 +1572,13 @@ QGraphicsAnchor *QGraphicsAnchorLayoutPrivate::addAnchor(QGraphicsLayoutItem *fi
     correctEdgeDirection(firstItem, firstEdge, secondItem, secondEdge);
 
     AnchorData *data = new AnchorData;
-    if (!spacing) {
+    QGraphicsAnchor *graphicsAnchor = acquireGraphicsAnchor(data);
+
+    addAnchor_helper(firstItem, firstEdge, secondItem, secondEdge, data);
+
+    if (spacing) {
+        graphicsAnchor->setSpacing(*spacing);
+    } else {
         // If firstItem or secondItem is the layout itself, the spacing will default to 0.
         // Otherwise, the following matrix is used (questionmark means that the spacing
         // is queried from the style):
@@ -1173,47 +1591,49 @@ QGraphicsAnchor *QGraphicsAnchorLayoutPrivate::addAnchor(QGraphicsLayoutItem *fi
             || secondItem == q
             || pickEdge(firstEdge, Horizontal) == Qt::AnchorHorizontalCenter
             || oppositeEdge(firstEdge) != secondEdge) {
-            data->setFixedSize(0);
+            graphicsAnchor->setSpacing(0);
         } else {
-            data->unsetSize();
+            graphicsAnchor->unsetSpacing();
         }
-        addAnchor_helper(firstItem, firstEdge, secondItem, secondEdge, data);
-
-    } else if (*spacing >= 0) {
-        data->setFixedSize(*spacing);
-        addAnchor_helper(firstItem, firstEdge, secondItem, secondEdge, data);
-
-    } else {
-        data->setFixedSize(-*spacing);
-        addAnchor_helper(secondItem, secondEdge, firstItem, firstEdge, data);
     }
 
-    return acquireGraphicsAnchor(data);
+    return graphicsAnchor;
 }
 
+/*
+  \internal
+
+  This method adds an AnchorData to the internal graph. It is responsible for doing
+  the boilerplate part of such task.
+
+  If another AnchorData exists between the mentioned vertices, it is deleted and
+  the new one is inserted.
+*/
 void QGraphicsAnchorLayoutPrivate::addAnchor_helper(QGraphicsLayoutItem *firstItem,
-                                             Qt::AnchorPoint firstEdge,
-                                             QGraphicsLayoutItem *secondItem,
-                                             Qt::AnchorPoint secondEdge,
-                                             AnchorData *data)
+                                                    Qt::AnchorPoint firstEdge,
+                                                    QGraphicsLayoutItem *secondItem,
+                                                    Qt::AnchorPoint secondEdge,
+                                                    AnchorData *data)
 {
     Q_Q(QGraphicsAnchorLayout);
 
-    // Guarantee that the graph is no simplified when adding this anchor,
-    // anchor manipulation always happen in the full graph
-    restoreSimplifiedGraph(edgeOrientation(firstEdge));
+    const Orientation orientation = edgeOrientation(firstEdge);
 
-    // Is the Vertex (firstItem, firstEdge) already represented in our
-    // internal structure?
+    // Create or increase the reference count for the related vertices.
     AnchorVertex *v1 = addInternalVertex(firstItem, firstEdge);
     AnchorVertex *v2 = addInternalVertex(secondItem, secondEdge);
 
     // Remove previous anchor
-    // ### Could we update the existing edgeData rather than creating a new one?
-    if (graph[edgeOrientation(firstEdge)].edgeData(v1, v2)) {
+    if (graph[orientation].edgeData(v1, v2)) {
         removeAnchor_helper(v1, v2);
     }
 
+    // If its an internal anchor, set the associated item
+    if (firstItem == secondItem)
+        data->item = firstItem;
+
+    data->orientation = orientation;
+
     // Create a bi-directional edge in the sense it can be transversed both
     // from v1 or v2. "data" however is shared between the two references
     // so we still know that the anchor direction is from 1 to 2.
@@ -1222,10 +1642,11 @@ void QGraphicsAnchorLayoutPrivate::addAnchor_helper(QGraphicsLayoutItem *firstIt
 #ifdef QT_DEBUG
     data->name = QString::fromAscii("%1 --to--> %2").arg(v1->toString()).arg(v2->toString());
 #endif
-    // Keep track of anchors that are connected to the layout 'edges'
-    data->isLayoutAnchor = (v1->m_item == q || v2->m_item == q);
+    // ### bit to track internal anchors, since inside AnchorData methods
+    // we don't have access to the 'q' pointer.
+    data->isLayoutAnchor = (data->item == q);
 
-    graph[edgeOrientation(firstEdge)].createEdge(v1, v2, data);
+    graph[orientation].createEdge(v1, v2, data);
 }
 
 QGraphicsAnchor *QGraphicsAnchorLayoutPrivate::getAnchor(QGraphicsLayoutItem *firstItem,
@@ -1233,15 +1654,13 @@ QGraphicsAnchor *QGraphicsAnchorLayoutPrivate::getAnchor(QGraphicsLayoutItem *fi
                                                          QGraphicsLayoutItem *secondItem,
                                                          Qt::AnchorPoint secondEdge)
 {
-    Orientation orient = edgeOrientation(firstEdge);
-    restoreSimplifiedGraph(orient);
-
+    const Orientation orientation = edgeOrientation(firstEdge);
     AnchorVertex *v1 = internalVertex(firstItem, firstEdge);
     AnchorVertex *v2 = internalVertex(secondItem, secondEdge);
 
     QGraphicsAnchor *graphicsAnchor = 0;
 
-    AnchorData *data = graph[orient].edgeData(v1, v2);
+    AnchorData *data = graph[orientation].edgeData(v1, v2);
     if (data)
         graphicsAnchor = acquireGraphicsAnchor(data);
     return graphicsAnchor;
@@ -1326,12 +1745,9 @@ void QGraphicsAnchorLayoutPrivate::removeAnchor(AnchorVertex *firstVertex,
 void QGraphicsAnchorLayoutPrivate::removeAnchor_helper(AnchorVertex *v1, AnchorVertex *v2)
 {
     Q_ASSERT(v1 && v2);
-    // Guarantee that the graph is no simplified when removing this anchor,
-    // anchor manipulation always happen in the full graph
-    Orientation o = edgeOrientation(v1->m_edge);
-    restoreSimplifiedGraph(o);
 
     // Remove edge from graph
+    const Orientation o = edgeOrientation(v1->m_edge);
     graph[o].removeEdge(v1, v2);
 
     // Decrease vertices reference count (may trigger a deletion)
@@ -1339,67 +1755,6 @@ void QGraphicsAnchorLayoutPrivate::removeAnchor_helper(AnchorVertex *v1, AnchorV
     removeInternalVertex(v2->m_item, v2->m_edge);
 }
 
-/*!
-    \internal
-    Only called from outside. (calls invalidate())
-*/
-void QGraphicsAnchorLayoutPrivate::setAnchorSize(AnchorData *data, const qreal *anchorSize)
-{
-    Q_Q(QGraphicsAnchorLayout);
-    // ### we can avoid restoration if we really want to, but we would have to
-    // search recursively through all composite anchors
-    Q_ASSERT(data);
-    restoreSimplifiedGraph(edgeOrientation(data->from->m_edge));
-
-    QGraphicsLayoutItem *firstItem = data->from->m_item;
-    QGraphicsLayoutItem *secondItem = data->to->m_item;
-    Qt::AnchorPoint firstEdge = data->from->m_edge;
-    Qt::AnchorPoint secondEdge = data->to->m_edge;
-
-    // Use heuristics to find out what the user meant with this anchor.
-    correctEdgeDirection(firstItem, firstEdge, secondItem, secondEdge);
-    if (data->from->m_item != firstItem)
-        qSwap(data->from, data->to);
-
-    if (anchorSize) {
-        // ### The current implementation makes "setAnchorSize" behavior
-        //     dependent on the argument order for cases where we have
-        //     no heuristic. Ie. two widgets, same anchor point.
-
-        // We cannot have negative sizes inside the graph. This would cause
-        // the simplex solver to fail because all simplex variables are
-        // positive by definition.
-        // "negative spacing" is handled by inverting the standard item order.
-        if (*anchorSize >= 0) {
-            data->setFixedSize(*anchorSize);
-        } else {
-            data->setFixedSize(-*anchorSize);
-            qSwap(data->from, data->to);
-        }
-    } else {
-        data->unsetSize();
-    }
-    q->invalidate();
-}
-
-void QGraphicsAnchorLayoutPrivate::anchorSize(const AnchorData *data,
-                                              qreal *minSize,
-                                              qreal *prefSize,
-                                              qreal *maxSize) const
-{
-    Q_ASSERT(minSize || prefSize || maxSize);
-    Q_ASSERT(data);
-    QGraphicsAnchorLayoutPrivate *that = const_cast<QGraphicsAnchorLayoutPrivate *>(this);
-    that->restoreSimplifiedGraph(edgeOrientation(data->from->m_edge));
-
-    if (minSize)
-        *minSize = data->minSize;
-    if (prefSize)
-        *prefSize = data->prefSize;
-    if (maxSize)
-        *maxSize = data->maxSize;
-}
-
 AnchorVertex *QGraphicsAnchorLayoutPrivate::addInternalVertex(QGraphicsLayoutItem *item,
                                                               Qt::AnchorPoint edge)
 {
@@ -1465,8 +1820,6 @@ void QGraphicsAnchorLayoutPrivate::removeVertex(QGraphicsLayoutItem *item, Qt::A
 
 void QGraphicsAnchorLayoutPrivate::removeAnchors(QGraphicsLayoutItem *item)
 {
-    Q_ASSERT(!graphSimplified[Horizontal] && !graphSimplified[Vertical]);
-
     // remove the center anchor first!!
     removeCenterAnchors(item, Qt::AnchorHorizontalCenter, false);
     removeVertex(item, Qt::AnchorLeft);
@@ -1530,27 +1883,32 @@ void QGraphicsAnchorLayoutPrivate::correctEdgeDirection(QGraphicsLayoutItem *&fi
     }
 }
 
-qreal QGraphicsAnchorLayoutPrivate::effectiveSpacing(Orientation orientation) const
+QLayoutStyleInfo &QGraphicsAnchorLayoutPrivate::styleInfo() const
 {
-    Q_Q(const QGraphicsAnchorLayout);
-    qreal s = spacings[orientation];
-    if (s < 0) {
-        // ### make sure behaviour is the same as in QGraphicsGridLayout
+    if (styleInfoDirty) {
+        Q_Q(const QGraphicsAnchorLayout);
+        //### Fix this if QGV ever gets support for Metal style or different Aqua sizes.
+        QWidget *wid = 0;
+
         QGraphicsLayoutItem *parent = q->parentLayoutItem();
         while (parent && parent->isLayout()) {
             parent = parent->parentLayoutItem();
         }
+        QGraphicsWidget *w = 0;
         if (parent) {
             QGraphicsItem *parentItem = parent->graphicsItem();
-            if (parentItem && parentItem->isWidget()) {
-                QGraphicsWidget *w = static_cast<QGraphicsWidget*>(parentItem);
-                s = w->style()->pixelMetric(orientation == Horizontal
-                                            ? QStyle::PM_LayoutHorizontalSpacing
-                                            : QStyle::PM_LayoutVerticalSpacing);
-            }
+            if (parentItem && parentItem->isWidget())
+                w = static_cast<QGraphicsWidget*>(parentItem);
         }
+
+        QStyle *style = w ? w->style() : QApplication::style();
+        cachedStyleInfo = QLayoutStyleInfo(style, wid);
+        cachedStyleInfo.setDefaultSpacing(Qt::Horizontal, spacings[0]);
+        cachedStyleInfo.setDefaultSpacing(Qt::Vertical, spacings[1]);
+
+        styleInfoDirty = false;
     }
-    return s;
+    return cachedStyleInfo;
 }
 
 /*!
@@ -1564,19 +1922,18 @@ void QGraphicsAnchorLayoutPrivate::calculateGraphs()
 {
     if (!calculateGraphCacheDirty)
         return;
-
     calculateGraphs(Horizontal);
     calculateGraphs(Vertical);
-
-    calculateGraphCacheDirty = 0;
+    calculateGraphCacheDirty = false;
 }
 
-// ### remove me:
+// ### Maybe getGraphParts could return the variables when traversing, at least
+// for trunk...
 QList<AnchorData *> getVariables(QList<QSimplexConstraint *> constraints)
 {
     QSet<AnchorData *> variableSet;
     for (int i = 0; i < constraints.count(); ++i) {
-        const QSimplexConstraint *c = constraints[i];
+        const QSimplexConstraint *c = constraints.at(i);
         foreach (QSimplexVariable *var, c->variables.keys()) {
             variableSet += static_cast<AnchorData *>(var);
         }
@@ -1585,38 +1942,46 @@ QList<AnchorData *> getVariables(QList<QSimplexConstraint *> constraints)
 }
 
 /*!
-  \internal
+    \internal
 
-  Calculate graphs is the method that puts together all the helper routines
-  so that the AnchorLayout can calculate the sizes of each item.
+    Calculate graphs is the method that puts together all the helper routines
+    so that the AnchorLayout can calculate the sizes of each item.
 
-  In a nutshell it should do:
+    In a nutshell it should do:
 
-  1) Update anchor nominal sizes, that is, the size that each anchor would
-     have if no other restrictions applied. This is done by quering the
-     layout style and the sizeHints of the items belonging to the layout.
+    1) Refresh anchor nominal sizes, that is, the size that each anchor would
+       have if no other restrictions applied. This is done by quering the
+       layout style and the sizeHints of the items belonging to the layout.
 
-  2) Simplify the graph by grouping together parallel and sequential anchors
-     into "group anchors". These have equivalent minimum, preferred and maximum
-     sizeHints as the anchors they replace.
+    2) Simplify the graph by grouping together parallel and sequential anchors
+       into "group anchors". These have equivalent minimum, preferred and maximum
+       sizeHints as the anchors they replace.
 
-  3) Check if we got to a trivial case. In some cases, the whole graph can be
-     simplified into a single anchor. If so, use this information. If not,
-     then call the Simplex solver to calculate the anchors sizes.
+    3) Check if we got to a trivial case. In some cases, the whole graph can be
+       simplified into a single anchor. If so, use this information. If not,
+       then call the Simplex solver to calculate the anchors sizes.
 
-  4) Once the root anchors had its sizes calculated, propagate that to the
-     anchors they represent.
+    4) Once the root anchors had its sizes calculated, propagate that to the
+       anchors they represent.
 */
 void QGraphicsAnchorLayoutPrivate::calculateGraphs(
     QGraphicsAnchorLayoutPrivate::Orientation orientation)
 {
-    Q_Q(QGraphicsAnchorLayout);
+#if defined(QT_DEBUG) || defined(Q_AUTOTEST_EXPORT)
+    lastCalculationUsedSimplex[orientation] = false;
+#endif
 
-    // Simplify the graph
-    simplifyGraph(orientation);
+    static bool simplificationEnabled = qgetenv("QT_ANCHORLAYOUT_NO_SIMPLIFICATION").isEmpty();
 
     // Reset the nominal sizes of each anchor based on the current item sizes
-    setAnchorSizeHintsFromItems(orientation);
+    refreshAllSizeHints(orientation);
+
+    // Simplify the graph
+    if (simplificationEnabled && !simplifyGraph(orientation)) {
+        qWarning("QGraphicsAnchorLayout: anchor setup is not feasible.");
+        graphHasConflicts[orientation] = true;
+        return;
+    }
 
     // Traverse all graph edges and store the possible paths to each vertex
     findPaths(orientation);
@@ -1635,163 +2000,161 @@ void QGraphicsAnchorLayoutPrivate::calculateGraphs(
     //  2) The floating or semi-floating anchors (items) that are those which
     //     are connected to only one (or none) of the layout sides, thus are not
     //     influenced by the layout size.
-    QList<QList<QSimplexConstraint *> > parts;
-    parts = getGraphParts(orientation);
+    QList<QList<QSimplexConstraint *> > parts = getGraphParts(orientation);
 
     // Now run the simplex solver to calculate Minimum, Preferred and Maximum sizes
     // of the "trunk" set of constraints and variables.
     // ### does trunk always exist? empty = trunk is the layout left->center->right
-    QList<QSimplexConstraint *> trunkConstraints = parts[0];
-    QList<QSimplexConstraint *> sizeHintConstraints;
-    sizeHintConstraints = constraintsFromSizeHints(getVariables(trunkConstraints));
-    trunkConstraints += sizeHintConstraints;
+    QList<QSimplexConstraint *> trunkConstraints = parts.at(0);
+    QList<AnchorData *> trunkVariables = getVariables(trunkConstraints);
 
     // For minimum and maximum, use the path between the two layout sides as the
     // objective function.
-
-    // Retrieve that path
-    AnchorVertex *v = internalVertex(q, pickEdge(Qt::AnchorRight, orientation));
+    AnchorVertex *v = layoutLastVertex[orientation];
     GraphPath trunkPath = graphPaths[orientation].value(v);
 
-    bool feasible = true;
-    if (!trunkConstraints.isEmpty()) {
-#if 0
-        qDebug("Simplex used for trunk of %s",
-               orientation == Horizontal ? "Horizontal" : "Vertical");
-#endif
+    bool feasible = calculateTrunk(orientation, trunkPath, trunkConstraints, trunkVariables);
 
-        // Solve min and max size hints for trunk
-        qreal min, max;
-        feasible = solveMinMax(trunkConstraints, trunkPath, &min, &max);
+    // For the other parts that not the trunk, solve only for the preferred size
+    // that is the size they will remain at, since they are not stretched by the
+    // layout.
 
-        if (feasible) {
-            // Solve for preferred. The objective function is calculated from the constraints
-            // and variables internally.
-            solvePreferred(trunkConstraints);
+    // Skipping the first (trunk)
+    for (int i = 1; i < parts.count(); ++i) {
+        if (!feasible)
+            break;
+
+        QList<QSimplexConstraint *> partConstraints = parts.at(i);
+        QList<AnchorData *> partVariables = getVariables(partConstraints);
+        Q_ASSERT(!partVariables.isEmpty());
+        feasible &= calculateNonTrunk(partConstraints, partVariables);
+    }
+
+    // Propagate the new sizes down the simplified graph, ie. tell the
+    // group anchors to set their children anchors sizes.
+    updateAnchorSizes(orientation);
+
+    graphHasConflicts[orientation] = !feasible;
+
+    // Clean up our data structures. They are not needed anymore since
+    // distribution uses just interpolation.
+    qDeleteAll(constraints[orientation]);
+    constraints[orientation].clear();
+    graphPaths[orientation].clear(); // ###
+
+    if (simplificationEnabled)
+        restoreSimplifiedGraph(orientation);
+}
+
+/*!
+    \internal
+
+    Calculate the sizes for all anchors which are part of the trunk. This works
+    on top of a (possibly) simplified graph.
+*/
+bool QGraphicsAnchorLayoutPrivate::calculateTrunk(Orientation orientation, const GraphPath &path,
+                                                  const QList<QSimplexConstraint *> &constraints,
+                                                  const QList<AnchorData *> &variables)
+{
+    bool feasible = true;
+    bool needsSimplex = !constraints.isEmpty();
 
-            // remove sizeHintConstraints from trunkConstraints
-            trunkConstraints = parts[0];
+#if 0
+    qDebug("Simplex %s for trunk of %s", needsSimplex ? "used" : "NOT used",
+           orientation == Horizontal ? "Horizontal" : "Vertical");
+#endif
 
-            // Solve for expanding. The objective function and the constraints from items
-            // are calculated internally.
-            solveExpanding(trunkConstraints);
+    if (needsSimplex) {
 
-            // Propagate the new sizes down the simplified graph, ie. tell the
-            // group anchors to set their children anchors sizes.
+        QList<QSimplexConstraint *> sizeHintConstraints = constraintsFromSizeHints(variables);
+        QList<QSimplexConstraint *> allConstraints = constraints + sizeHintConstraints;
 
-            // ### we calculated variables already a few times, can't we reuse that?
-            QList<AnchorData *> trunkVariables = getVariables(trunkConstraints);
+        // Solve min and max size hints
+        qreal min, max;
+        feasible = solveMinMax(allConstraints, path, &min, &max);
 
-            for (int i = 0; i < trunkVariables.count(); ++i)
-                trunkVariables.at(i)->updateChildrenSizes();
+        if (feasible) {
+            solvePreferred(allConstraints, variables);
 
-            // Calculate and set the preferred and expanding sizes for the layout,
+            // Calculate and set the preferred size for the layout,
             // from the edge sizes that were calculated above.
             qreal pref(0.0);
-            qreal expanding(0.0);
-            foreach (const AnchorData *ad, trunkPath.positives) {
+            foreach (const AnchorData *ad, path.positives) {
                 pref += ad->sizeAtPreferred;
-                expanding += ad->sizeAtExpanding;
             }
-            foreach (const AnchorData *ad, trunkPath.negatives) {
+            foreach (const AnchorData *ad, path.negatives) {
                 pref -= ad->sizeAtPreferred;
-                expanding -= ad->sizeAtExpanding;
             }
 
             sizeHints[orientation][Qt::MinimumSize] = min;
             sizeHints[orientation][Qt::PreferredSize] = pref;
             sizeHints[orientation][Qt::MaximumSize] = max;
-            sizeAtExpanding[orientation] = expanding;
         }
-    } else {
-#if 0
-        qDebug("Simplex NOT used for trunk of %s",
-               orientation == Horizontal ? "Horizontal" : "Vertical");
-#endif
 
+        qDeleteAll(sizeHintConstraints);
+
+    } else {
         // No Simplex is necessary because the path was simplified all the way to a single
         // anchor.
-        Q_ASSERT(trunkPath.positives.count() == 1);
-        Q_ASSERT(trunkPath.negatives.count() == 0);
+        Q_ASSERT(path.positives.count() == 1);
+        Q_ASSERT(path.negatives.count() == 0);
 
-        AnchorData *ad = trunkPath.positives.toList()[0];
+        AnchorData *ad = path.positives.toList()[0];
         ad->sizeAtMinimum = ad->minSize;
         ad->sizeAtPreferred = ad->prefSize;
-        ad->sizeAtExpanding = ad->expSize;
         ad->sizeAtMaximum = ad->maxSize;
 
-        // Propagate
-        ad->updateChildrenSizes();
-
         sizeHints[orientation][Qt::MinimumSize] = ad->sizeAtMinimum;
         sizeHints[orientation][Qt::PreferredSize] = ad->sizeAtPreferred;
         sizeHints[orientation][Qt::MaximumSize] = ad->sizeAtMaximum;
-        sizeAtExpanding[orientation] = ad->sizeAtExpanding;
     }
 
-    // Delete the constraints, we won't use them anymore.
-    qDeleteAll(sizeHintConstraints);
-    sizeHintConstraints.clear();
+#if defined(QT_DEBUG) || defined(Q_AUTOTEST_EXPORT)
+    lastCalculationUsedSimplex[orientation] = needsSimplex;
+#endif
 
-    // For the other parts that not the trunk, solve only for the preferred size
-    // that is the size they will remain at, since they are not stretched by the
-    // layout.
+    return feasible;
+}
 
-    // Solve the other only for preferred, skip trunk
-    if (feasible) {
-        for (int i = 1; i < parts.count(); ++i) {
-            QList<QSimplexConstraint *> partConstraints = parts[i];
-            QList<AnchorData *> partVariables = getVariables(partConstraints);
-            Q_ASSERT(!partVariables.isEmpty());
-
-            sizeHintConstraints = constraintsFromSizeHints(partVariables);
-            partConstraints += sizeHintConstraints;
-            feasible &= solvePreferred(partConstraints);
-            if (!feasible)
-                break;
-
-            // Propagate size at preferred to other sizes. Semi-floats
-            // always will be in their sizeAtPreferred.
-            for (int j = 0; j < partVariables.count(); ++j) {
-                AnchorData *ad = partVariables[j];
-                Q_ASSERT(ad);
-                ad->sizeAtMinimum = ad->sizeAtPreferred;
-                ad->sizeAtExpanding = ad->sizeAtPreferred;
-                ad->sizeAtMaximum = ad->sizeAtPreferred;
-                ad->updateChildrenSizes();
-            }
+/*!
+    \internal
+*/
+bool QGraphicsAnchorLayoutPrivate::calculateNonTrunk(const QList<QSimplexConstraint *> &constraints,
+                                                     const QList<AnchorData *> &variables)
+{
+    QList<QSimplexConstraint *> sizeHintConstraints = constraintsFromSizeHints(variables);
+    bool feasible = solvePreferred(constraints + sizeHintConstraints, variables);
 
-            // Delete the constraints, we won't use them anymore.
-            qDeleteAll(sizeHintConstraints);
-            sizeHintConstraints.clear();
+    if (feasible) {
+        // Propagate size at preferred to other sizes. Semi-floats always will be
+        // in their sizeAtPreferred.
+        for (int j = 0; j < variables.count(); ++j) {
+            AnchorData *ad = variables.at(j);
+            Q_ASSERT(ad);
+            ad->sizeAtMinimum = ad->sizeAtPreferred;
+            ad->sizeAtMaximum = ad->sizeAtPreferred;
         }
     }
-    graphHasConflicts[orientation] = !feasible;
 
-    // Clean up our data structures. They are not needed anymore since
-    // distribution uses just interpolation.
-    qDeleteAll(constraints[orientation]);
-    constraints[orientation].clear();
-    graphPaths[orientation].clear(); // ###
+    qDeleteAll(sizeHintConstraints);
+    return feasible;
 }
 
 /*!
-  \internal
+    \internal
 
-  For graph edges ("anchors") that represent items, this method updates their
-  intrinsic size restrictions, based on the item size hints.
+    Traverse the graph refreshing the size hints. Edges will query their associated
+    item or graphicsAnchor for their size hints.
 */
-void QGraphicsAnchorLayoutPrivate::setAnchorSizeHintsFromItems(Orientation orientation)
+void QGraphicsAnchorLayoutPrivate::refreshAllSizeHints(Orientation orientation)
 {
     Graph<AnchorVertex, AnchorData> &g = graph[orientation];
     QList<QPair<AnchorVertex *, AnchorVertex *> > vertices = g.connections();
 
-    qreal spacing = effectiveSpacing(orientation);
-
+    QLayoutStyleInfo styleInf = styleInfo();
     for (int i = 0; i < vertices.count(); ++i) {
-        AnchorData *data = g.edgeData(vertices.at(i).first, vertices.at(i).second);;
-        Q_ASSERT(data->from && data->to);
-        data->refreshSizeHints(spacing);
+        AnchorData *data = g.edgeData(vertices.at(i).first, vertices.at(i).second);
+        data->refreshSizeHints(&styleInf);
     }
 }
 
@@ -1811,7 +2174,7 @@ void QGraphicsAnchorLayoutPrivate::findPaths(Orientation orientation)
 
     QSet<AnchorData *> visited;
 
-    AnchorVertex *root = graph[orientation].rootVertex();
+    AnchorVertex *root = layoutFirstVertex[orientation];
 
     graphPaths[orientation].insert(root, GraphPath());
 
@@ -1869,13 +2232,27 @@ void QGraphicsAnchorLayoutPrivate::constraintsFromPaths(Orientation orientation)
         QList<GraphPath> pathsToVertex = graphPaths[orientation].values(vertex);
         for (int i = 1; i < valueCount; ++i) {
             constraints[orientation] += \
-                pathsToVertex[0].constraint(pathsToVertex[i]);
+                pathsToVertex[0].constraint(pathsToVertex.at(i));
         }
     }
 }
 
 /*!
   \internal
+*/
+void QGraphicsAnchorLayoutPrivate::updateAnchorSizes(Orientation orientation)
+{
+    Graph<AnchorVertex, AnchorData> &g = graph[orientation];
+    const QList<QPair<AnchorVertex *, AnchorVertex *> > &vertices = g.connections();
+
+    for (int i = 0; i < vertices.count(); ++i) {
+        AnchorData *ad = g.edgeData(vertices.at(i).first, vertices.at(i).second);
+        ad->updateChildrenSizes();
+    }
+}
+
+/*!
+  \internal
 
   Create LP constraints for each anchor based on its minimum and maximum
   sizes, as specified in its size hints
@@ -1883,17 +2260,72 @@ void QGraphicsAnchorLayoutPrivate::constraintsFromPaths(Orientation orientation)
 QList<QSimplexConstraint *> QGraphicsAnchorLayoutPrivate::constraintsFromSizeHints(
     const QList<AnchorData *> &anchors)
 {
+    if (anchors.isEmpty())
+        return QList<QSimplexConstraint *>();
+
+    // Look for the layout edge. That can be either the first half in case the
+    // layout is split in two, or the whole layout anchor.
+    Orientation orient = Orientation(anchors.first()->orientation);
+    AnchorData *layoutEdge = 0;
+    if (layoutCentralVertex[orient]) {
+        layoutEdge = graph[orient].edgeData(layoutFirstVertex[orient], layoutCentralVertex[orient]);
+    } else {
+        layoutEdge = graph[orient].edgeData(layoutFirstVertex[orient], layoutLastVertex[orient]);
+
+        // If maxSize is less then "infinite", that means there are other anchors
+        // grouped together with this one. We can't ignore its maximum value so we
+        // set back the variable to NULL to prevent the continue condition from being
+        // satisfied in the loop below.
+        if (layoutEdge->maxSize < QWIDGETSIZE_MAX)
+            layoutEdge = 0;
+    }
+
+    // For each variable, create constraints based on size hints
     QList<QSimplexConstraint *> anchorConstraints;
+    bool unboundedProblem = true;
     for (int i = 0; i < anchors.size(); ++i) {
-        QSimplexConstraint *c = new QSimplexConstraint;
-        c->variables.insert(anchors[i], 1.0);
-        c->constant = anchors[i]->minSize;
-        c->ratio = QSimplexConstraint::MoreOrEqual;
-        anchorConstraints += c;
+        AnchorData *ad = anchors.at(i);
+
+        // Anchors that have their size directly linked to another one don't need constraints
+        // For exammple, the second half of an item has exactly the same size as the first half
+        // thus constraining the latter is enough.
+        if (ad->dependency == AnchorData::Slave)
+            continue;
+
+        if ((ad->minSize == ad->maxSize) || qFuzzyCompare(ad->minSize, ad->maxSize)) {
+            QSimplexConstraint *c = new QSimplexConstraint;
+            c->variables.insert(ad, 1.0);
+            c->constant = ad->minSize;
+            c->ratio = QSimplexConstraint::Equal;
+            anchorConstraints += c;
+            unboundedProblem = false;
+        } else {
+            QSimplexConstraint *c = new QSimplexConstraint;
+            c->variables.insert(ad, 1.0);
+            c->constant = ad->minSize;
+            c->ratio = QSimplexConstraint::MoreOrEqual;
+            anchorConstraints += c;
+
+            // We avoid adding restrictions to the layout internal anchors. That's
+            // to prevent unnecessary fair distribution from happening due to this
+            // artificial restriction.
+            if (ad == layoutEdge)
+                continue;
 
-        c = new QSimplexConstraint;
-        c->variables.insert(anchors[i], 1.0);
-        c->constant = anchors[i]->maxSize;
+            c = new QSimplexConstraint;
+            c->variables.insert(ad, 1.0);
+            c->constant = ad->maxSize;
+            c->ratio = QSimplexConstraint::LessOrEqual;
+            anchorConstraints += c;
+            unboundedProblem = false;
+        }
+    }
+
+    // If no upper boundary restriction was added, add one to avoid unbounded problem
+    if (unboundedProblem) {
+        QSimplexConstraint *c = new QSimplexConstraint;
+        c->variables.insert(layoutEdge, 1.0);
+        c->constant = QWIDGETSIZE_MAX;
         c->ratio = QSimplexConstraint::LessOrEqual;
         anchorConstraints += c;
     }
@@ -1907,38 +2339,26 @@ QList<QSimplexConstraint *> QGraphicsAnchorLayoutPrivate::constraintsFromSizeHin
 QList< QList<QSimplexConstraint *> >
 QGraphicsAnchorLayoutPrivate::getGraphParts(Orientation orientation)
 {
-    Q_Q(QGraphicsAnchorLayout);
-
-    // Find layout vertices and edges for the current orientation.
-    AnchorVertex *layoutFirstVertex = \
-        internalVertex(q, pickEdge(Qt::AnchorLeft, orientation));
-
-    AnchorVertex *layoutCentralVertex = \
-        internalVertex(q, pickEdge(Qt::AnchorHorizontalCenter, orientation));
-
-    AnchorVertex *layoutLastVertex = \
-        internalVertex(q, pickEdge(Qt::AnchorRight, orientation));
+    Q_ASSERT(layoutFirstVertex[orientation] && layoutLastVertex[orientation]);
 
-    Q_ASSERT(layoutFirstVertex && layoutLastVertex);
-
-    AnchorData *edgeL1 = NULL;
-    AnchorData *edgeL2 = NULL;
+    AnchorData *edgeL1 = 0;
+    AnchorData *edgeL2 = 0;
 
     // The layout may have a single anchor between Left and Right or two half anchors
     // passing through the center
-    if (layoutCentralVertex) {
-        edgeL1 = graph[orientation].edgeData(layoutFirstVertex, layoutCentralVertex);
-        edgeL2 = graph[orientation].edgeData(layoutCentralVertex, layoutLastVertex);
+    if (layoutCentralVertex[orientation]) {
+        edgeL1 = graph[orientation].edgeData(layoutFirstVertex[orientation], layoutCentralVertex[orientation]);
+        edgeL2 = graph[orientation].edgeData(layoutCentralVertex[orientation], layoutLastVertex[orientation]);
     } else {
-        edgeL1 = graph[orientation].edgeData(layoutFirstVertex, layoutLastVertex);
+        edgeL1 = graph[orientation].edgeData(layoutFirstVertex[orientation], layoutLastVertex[orientation]);
     }
 
     QLinkedList<QSimplexConstraint *> remainingConstraints;
     for (int i = 0; i < constraints[orientation].count(); ++i) {
-        remainingConstraints += constraints[orientation][i];
+        remainingConstraints += constraints[orientation].at(i);
     }
     for (int i = 0; i < itemCenterConstraints[orientation].count(); ++i) {
-        remainingConstraints += itemCenterConstraints[orientation][i];
+        remainingConstraints += itemCenterConstraints[orientation].at(i);
     }
 
     QList<QSimplexConstraint *> trunkConstraints;
@@ -2035,8 +2455,8 @@ void QGraphicsAnchorLayoutPrivate::identifyNonFloatItems_helper(const AnchorData
 
     switch(ad->type) {
     case AnchorData::Normal:
-        if (ad->from->m_item == ad->to->m_item && ad->to->m_item != q)
-            nonFloatingItemsIdentifiedSoFar->insert(ad->to->m_item);
+        if (ad->item && ad->item != q)
+            nonFloatingItemsIdentifiedSoFar->insert(ad->item);
         break;
     case AnchorData::Sequential:
         foreach (const AnchorData *d, static_cast<const SequentialAnchorData *>(ad)->m_edges)
@@ -2120,7 +2540,7 @@ void QGraphicsAnchorLayoutPrivate::calculateVertexPositions(
     QSet<AnchorVertex *> visited;
 
     // Get root vertex
-    AnchorVertex *root = graph[orientation].rootVertex();
+    AnchorVertex *root = layoutFirstVertex[orientation];
 
     root->distance = 0;
     visited.insert(root);
@@ -2133,20 +2553,16 @@ void QGraphicsAnchorLayoutPrivate::calculateVertexPositions(
     // Do initial calculation required by "interpolateEdge()"
     setupEdgesInterpolation(orientation);
 
-    // Traverse the graph and calculate vertex positions, we need to
-    // visit all pairs since each of them could have a sequential
-    // anchor inside, which hides more vertices.
+    // Traverse the graph and calculate vertex positions
     while (!queue.isEmpty()) {
         QPair<AnchorVertex *, AnchorVertex *> pair = queue.dequeue();
         AnchorData *edge = graph[orientation].edgeData(pair.first, pair.second);
 
-        // Both vertices were interpolated, and the anchor itself can't have other
-        // anchors inside (it's not a complex anchor).
-        if (edge->type == AnchorData::Normal && visited.contains(pair.second))
+        if (visited.contains(pair.second))
             continue;
 
         visited.insert(pair.second);
-        interpolateEdge(pair.first, edge, orientation);
+        interpolateEdge(pair.first, edge);
 
         QList<AnchorVertex *> adjacents = graph[orientation].adjacentVertices(pair.second);
         for (int i = 0; i < adjacents.count(); ++i) {
@@ -2160,150 +2576,62 @@ void QGraphicsAnchorLayoutPrivate::calculateVertexPositions(
   \internal
 
   Calculate interpolation parameters based on current Layout Size.
-  Must once before calling "interpolateEdgeSize()" for each edge.
+  Must be called once before calling "interpolateEdgeSize()" for
+  the edges.
 */
 void QGraphicsAnchorLayoutPrivate::setupEdgesInterpolation(
     Orientation orientation)
 {
     Q_Q(QGraphicsAnchorLayout);
-    qreal lower, upper, current;
 
-    if (orientation == Horizontal) {
-        current = q->contentsRect().width();
-    } else {
-        current = q->contentsRect().height();
-    }
+    qreal current;
+    current = (orientation == Horizontal) ? q->contentsRect().width() : q->contentsRect().height();
 
-    if (current < sizeHints[orientation][Qt::PreferredSize]) {
-        interpolationInterval[orientation] = MinToPreferred;
-        lower = sizeHints[orientation][Qt::MinimumSize];
-        upper = sizeHints[orientation][Qt::PreferredSize];
-    } else if (current < sizeAtExpanding[orientation]) {
-        interpolationInterval[orientation] = PreferredToExpanding;
-        lower = sizeHints[orientation][Qt::PreferredSize];
-        upper = sizeAtExpanding[orientation];
-    } else {
-        interpolationInterval[orientation] = ExpandingToMax;
-        lower = sizeAtExpanding[orientation];
-        upper = sizeHints[orientation][Qt::MaximumSize];
-    }
+    QPair<Interval, qreal> result;
+    result = getFactor(current,
+                       sizeHints[orientation][Qt::MinimumSize],
+                       sizeHints[orientation][Qt::PreferredSize],
+                       sizeHints[orientation][Qt::MaximumSize]);
 
-    if (upper == lower) {
-        interpolationProgress[orientation] = 0;
-    } else {
-        interpolationProgress[orientation] = (current - lower) / (upper - lower);
-    }
+    interpolationInterval[orientation] = result.first;
+    interpolationProgress[orientation] = result.second;
 }
 
 /*!
-  \internal
-
-  Calculate the current Edge size based on the current Layout size and the
-  size the edge is supposed to have when the layout is at its:
+    \internal
 
-   - minimum size,
-   - preferred size,
-   - size when all expanding anchors are expanded,
-   - maximum size.
+    Calculate the current Edge size based on the current Layout size and the
+    size the edge is supposed to have when the layout is at its:
 
-   These three key values are calculated in advance using linear
-   programming (more expensive) or the simplification algorithm, then
-   subsequential resizes of the parent layout require a simple
-   interpolation.
+    - minimum size,
+    - preferred size,
+    - maximum size.
 
-   If the edge is sequential or parallel, it's possible to have more
-   vertices to be initalized, so it calls specialized functions that
-   will recurse back to interpolateEdge().
- */
-void QGraphicsAnchorLayoutPrivate::interpolateEdge(AnchorVertex *base,
-                                                   AnchorData *edge,
-                                                   Orientation orientation)
-{
-    qreal lower, upper;
-
-    if (interpolationInterval[orientation] == MinToPreferred) {
-        lower = edge->sizeAtMinimum;
-        upper = edge->sizeAtPreferred;
-    } else if (interpolationInterval[orientation] == PreferredToExpanding) {
-        lower = edge->sizeAtPreferred;
-        upper = edge->sizeAtExpanding;
-    } else {
-        lower = edge->sizeAtExpanding;
-        upper = edge->sizeAtMaximum;
-    }
+    These three key values are calculated in advance using linear
+    programming (more expensive) or the simplification algorithm, then
+    subsequential resizes of the parent layout require a simple
+    interpolation.
+*/
+void QGraphicsAnchorLayoutPrivate::interpolateEdge(AnchorVertex *base, AnchorData *edge)
+{
+    const Orientation orientation = Orientation(edge->orientation);
+    const QPair<Interval, qreal> factor(interpolationInterval[orientation],
+                                        interpolationProgress[orientation]);
 
-    qreal edgeDistance = (interpolationProgress[orientation] * (upper - lower)) + lower;
+    qreal edgeDistance = interpolate(factor, edge->sizeAtMinimum, edge->sizeAtPreferred,
+                                     edge->sizeAtMaximum);
 
     Q_ASSERT(edge->from == base || edge->to == base);
 
-    if (edge->from == base)
+    // Calculate the distance for the vertex opposite to the base
+    if (edge->from == base) {
         edge->to->distance = base->distance + edgeDistance;
-    else
+    } else {
         edge->from->distance = base->distance - edgeDistance;
+    }
+}
 
-    // Process child anchors
-    if (edge->type == AnchorData::Sequential)
-        interpolateSequentialEdges(edge->from,
-                                   static_cast<SequentialAnchorData *>(edge),
-                                   orientation);
-    else if (edge->type == AnchorData::Parallel)
-        interpolateParallelEdges(edge->from,
-                                 static_cast<ParallelAnchorData *>(edge),
-                                 orientation);
-}
-
-void QGraphicsAnchorLayoutPrivate::interpolateParallelEdges(
-    AnchorVertex *base, ParallelAnchorData *data, Orientation orientation)
-{
-    // In parallels the boundary vertices are already calculate, we
-    // just need to look for sequential groups inside, because only
-    // them may have new vertices associated.
-
-    // First edge
-    if (data->firstEdge->type == AnchorData::Sequential)
-        interpolateSequentialEdges(base,
-                                   static_cast<SequentialAnchorData *>(data->firstEdge),
-                                   orientation);
-    else if (data->firstEdge->type == AnchorData::Parallel)
-        interpolateParallelEdges(base,
-                                 static_cast<ParallelAnchorData *>(data->firstEdge),
-                                 orientation);
-
-    // Second edge
-    if (data->secondEdge->type == AnchorData::Sequential)
-        interpolateSequentialEdges(base,
-                                   static_cast<SequentialAnchorData *>(data->secondEdge),
-                                   orientation);
-    else if (data->secondEdge->type == AnchorData::Parallel)
-        interpolateParallelEdges(base,
-                                 static_cast<ParallelAnchorData *>(data->secondEdge),
-                                 orientation);
-}
-
-void QGraphicsAnchorLayoutPrivate::interpolateSequentialEdges(
-    AnchorVertex *base, SequentialAnchorData *data, Orientation orientation)
-{
-    AnchorVertex *prev = base;
-
-    // ### I'm not sure whether this assumption is safe. If not,
-    // consider that m_edges.last() could be used instead (so
-    // at(0) would be the one to be treated specially).
-    Q_ASSERT(base == data->m_edges.at(0)->to || base == data->m_edges.at(0)->from);
-
-    // Skip the last
-    for (int i = 0; i < data->m_edges.count() - 1; ++i) {
-        AnchorData *child = data->m_edges.at(i);
-        interpolateEdge(prev, child, orientation);
-        prev = child->to;
-    }
-
-    // Treat the last specially, since we already calculated it's end
-    // vertex, so it's only interesting if it's a complex one
-    if (data->m_edges.last()->type != AnchorData::Normal)
-        interpolateEdge(prev, data->m_edges.last(), orientation);
-}
-
-bool QGraphicsAnchorLayoutPrivate::solveMinMax(QList<QSimplexConstraint *> constraints,
+bool QGraphicsAnchorLayoutPrivate::solveMinMax(const QList<QSimplexConstraint *> &constraints,
                                                GraphPath path, qreal *min, qreal *max)
 {
     QSimplex simplex;
@@ -2324,11 +2652,12 @@ bool QGraphicsAnchorLayoutPrivate::solveMinMax(QList<QSimplexConstraint *> const
         *min = simplex.solveMin();
 
         // Save sizeAtMinimum results
-        QList<QSimplexVariable *> variables = simplex.constraintsVariables();
+        QList<AnchorData *> variables = getVariables(constraints);
         for (int i = 0; i < variables.size(); ++i) {
-            AnchorData *ad = static_cast<AnchorData *>(variables[i]);
-            Q_ASSERT(ad->result >= ad->minSize || qFuzzyCompare(ad->result, ad->minSize));
+            AnchorData *ad = static_cast<AnchorData *>(variables.at(i));
             ad->sizeAtMinimum = ad->result;
+            Q_ASSERT(ad->sizeAtMinimum >= ad->minSize ||
+                     qAbs(ad->sizeAtMinimum - ad->minSize) < 0.00000001);
         }
 
         // Calculate maximum values
@@ -2336,17 +2665,18 @@ bool QGraphicsAnchorLayoutPrivate::solveMinMax(QList<QSimplexConstraint *> const
 
         // Save sizeAtMaximum results
         for (int i = 0; i < variables.size(); ++i) {
-            AnchorData *ad = static_cast<AnchorData *>(variables[i]);
-            Q_ASSERT(ad->result <= ad->maxSize || qFuzzyCompare(ad->result, ad->maxSize));
+            AnchorData *ad = static_cast<AnchorData *>(variables.at(i));
             ad->sizeAtMaximum = ad->result;
+            // Q_ASSERT(ad->sizeAtMaximum <= ad->maxSize ||
+            //          qAbs(ad->sizeAtMaximum - ad->maxSize) < 0.00000001);
         }
     }
     return feasible;
 }
 
-bool QGraphicsAnchorLayoutPrivate::solvePreferred(QList<QSimplexConstraint *> constraints)
+bool QGraphicsAnchorLayoutPrivate::solvePreferred(const QList<QSimplexConstraint *> &constraints,
+                                                  const QList<AnchorData *> &variables)
 {
-    QList<AnchorData *> variables = getVariables(constraints);
     QList<QSimplexConstraint *> preferredConstraints;
     QList<QSimplexVariable *> preferredVariables;
     QSimplexConstraint objective;
@@ -2369,7 +2699,7 @@ bool QGraphicsAnchorLayoutPrivate::solvePreferred(QList<QSimplexConstraint *> co
     //      A + A_shrinker - A_grower = A_pref
     //
     for (int i = 0; i < variables.size(); ++i) {
-        AnchorData *ad = static_cast<AnchorData *>(variables[i]);
+        AnchorData *ad = variables.at(i);
         if (ad->skipInPreferred)
             continue;
 
@@ -2400,7 +2730,7 @@ bool QGraphicsAnchorLayoutPrivate::solvePreferred(QList<QSimplexConstraint *> co
 
         // Save sizeAtPreferred results
         for (int i = 0; i < variables.size(); ++i) {
-            AnchorData *ad = static_cast<AnchorData *>(variables[i]);
+            AnchorData *ad = variables.at(i);
             ad->sizeAtPreferred = ad->result;
         }
 
@@ -2417,139 +2747,6 @@ bool QGraphicsAnchorLayoutPrivate::solvePreferred(QList<QSimplexConstraint *> co
 
 /*!
     \internal
-    Calculate the "expanding" keyframe
-
-    This new keyframe sits between the already existing sizeAtPreferred and
-    sizeAtMaximum keyframes. Its goal is to modify the interpolation between
-    the latter as to respect the "expanding" size policy of some anchors.
-
-    Previously all items would be subject to a linear interpolation between
-    sizeAtPreferred and sizeAtMaximum values. This will change now, the
-    expanding anchors will change their size before the others. To calculate
-    this keyframe we use the following logic:
-
-    1) Ask each anchor for their desired expanding size (ad->expSize), this
-    value depends on the anchor expanding property in the following way:
-
-    - Expanding normal anchors want to grow towards their maximum size
-    - Non-expanding normal anchors want to remain at their preferred size.
-    - Sequential anchors wants to grow towards a size that is calculated by:
-        summarizing it's child anchors, where it will use preferred size for non-expanding anchors
-        and maximum size for expanding anchors.
-    - Parallel anchors want to grow towards the smallest maximum size of all the expanding anchors.
-
-    2) Clamp their desired values to the value they assume in the neighbour
-    keyframes (sizeAtPreferred and sizeAtExpanding)
-
-    3) Run simplex with a setup that ensures the following:
-
-      a. Anchors will change their value from their sizeAtPreferred towards
-         their sizeAtMaximum as much as required to ensure that ALL anchors
-         reach their respective "desired" expanding sizes.
-
-      b. No anchors will change their value beyond what is NEEDED to satisfy
-         the requirement above.
-
-    The final result is that, at the "expanding" keyframe expanding anchors
-    will grow and take with them all anchors that are parallel to them.
-    However, non-expanding anchors will remain at their preferred size unless
-    they are forced to grow by a parallel expanding anchor.
-
-    Note: For anchors where the sizeAtPreferred is bigger than sizeAtMaximum,
-          the visual effect when the layout grows from its preferred size is
-          the following: Expanding anchors will keep their size while non
-          expanding ones will shrink. Only after non-expanding anchors have
-          shrinked all the way, the expanding anchors will start to shrink too.
-*/
-void QGraphicsAnchorLayoutPrivate::solveExpanding(QList<QSimplexConstraint *> constraints)
-{
-    QList<AnchorData *> variables = getVariables(constraints);
-    QList<QSimplexConstraint *> itemConstraints;
-    QSimplexConstraint *objective = new QSimplexConstraint;
-    bool hasExpanding = false;
-
-    // Construct the simplex constraints and objective
-    for (int i = 0; i < variables.size(); ++i) {
-        // For each anchor
-        AnchorData *ad = variables[i];
-
-        // Clamp the desired expanding size
-        qreal upperBoundary = qMax(ad->sizeAtPreferred, ad->sizeAtMaximum);
-        qreal lowerBoundary = qMin(ad->sizeAtPreferred, ad->sizeAtMaximum);
-        qreal boundedExpSize = qBound(lowerBoundary, ad->expSize, upperBoundary);
-
-        // Expanding anchors are those that want to move from their preferred size
-        if (boundedExpSize != ad->sizeAtPreferred)
-            hasExpanding = true;
-
-        // Lock anchor between boundedExpSize and sizeAtMaximum (ensure 3.a)
-        if (boundedExpSize == ad->sizeAtMaximum) {
-            // The interval has only one possible value, we can use an "Equal"
-            // constraint and don't need to add this variable to the objective.
-            QSimplexConstraint *itemC = new QSimplexConstraint;
-            itemC->ratio = QSimplexConstraint::Equal;
-            itemC->variables.insert(ad, 1.0);
-            itemC->constant = boundedExpSize;
-            itemConstraints << itemC;
-        } else {
-            // Add MoreOrEqual and LessOrEqual constraints.
-            QSimplexConstraint *itemC = new QSimplexConstraint;
-            itemC->ratio = QSimplexConstraint::MoreOrEqual;
-            itemC->variables.insert(ad, 1.0);
-            itemC->constant = qMin(boundedExpSize, ad->sizeAtMaximum);
-            itemConstraints << itemC;
-
-            itemC = new QSimplexConstraint;
-            itemC->ratio = QSimplexConstraint::LessOrEqual;
-            itemC->variables.insert(ad, 1.0);
-            itemC->constant = qMax(boundedExpSize, ad->sizeAtMaximum);
-            itemConstraints << itemC;
-
-            // Create objective to avoid the anchors from moving away from
-            // the preferred size more than the needed amount. (ensure 3.b)
-            // The objective function is the distance between sizeAtPreferred
-            // and sizeAtExpanding, it will be minimized.
-            if (ad->sizeAtExpanding < ad->sizeAtMaximum) {
-                // Try to shrink this variable towards its sizeAtPreferred value
-                objective->variables.insert(ad, 1.0);
-            } else {
-                // Try to grow this variable towards its sizeAtPreferred value
-                objective->variables.insert(ad, -1.0);
-            }
-        }
-    }
-
-    // Solve
-    if (hasExpanding == false) {
-        // If no anchors are expanding, we don't need to run the simplex
-        // Set all variables to their preferred size
-        for (int i = 0; i < variables.size(); ++i) {
-            variables[i]->sizeAtExpanding = variables[i]->sizeAtPreferred;
-        }
-    } else {
-        // Run simplex
-        QSimplex simplex;
-
-        // Satisfy expanding (3.a)
-        bool feasible = simplex.setConstraints(constraints + itemConstraints);
-        Q_ASSERT(feasible);
-
-        // Reduce damage (3.b)
-        simplex.setObjective(objective);
-        simplex.solveMin();
-
-        // Collect results
-        for (int i = 0; i < variables.size(); ++i) {
-            variables[i]->sizeAtExpanding = variables[i]->result;
-        }
-    }
-
-    delete objective;
-    qDeleteAll(itemConstraints);
-}
-
-/*!
-    \internal
     Returns true if there are no arrangement that satisfies all constraints.
     Otherwise returns false.
 
@@ -2566,9 +2763,9 @@ bool QGraphicsAnchorLayoutPrivate::hasConflicts() const
 }
 
 #ifdef QT_DEBUG
-void QGraphicsAnchorLayoutPrivate::dumpGraph()
+void QGraphicsAnchorLayoutPrivate::dumpGraph(const QString &name)
 {
-    QFile file(QString::fromAscii("anchorlayout.dot"));
+    QFile file(QString::fromAscii("anchorlayout.%1.dot").arg(name));
     if (!file.open(QIODevice::WriteOnly | QIODevice::Text | QIODevice::Truncate))
         qWarning("Could not write to %s", file.fileName().toLocal8Bit().constData());
 
@@ -2582,3 +2779,4 @@ void QGraphicsAnchorLayoutPrivate::dumpGraph()
 #endif
 
 QT_END_NAMESPACE
+#endif //QT_NO_GRAPHICSVIEW
diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.h b/src/gui/graphicsview/qgraphicsanchorlayout_p.h
index 9ac0e19..2b365fb 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout_p.h
+++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.h
@@ -60,7 +60,7 @@
 #include "qgraphicsanchorlayout.h"
 #include "qgraph_p.h"
 #include "qsimplex_p.h"
-
+#ifndef QT_NO_GRAPHICSVIEW
 QT_BEGIN_NAMESPACE
 
 /*
@@ -78,66 +78,30 @@ QT_BEGIN_NAMESPACE
   Represents a vertex (anchorage point) in the internal graph
 */
 struct AnchorVertex {
+    enum Type {
+        Normal = 0,
+        Pair
+    };
+
     AnchorVertex(QGraphicsLayoutItem *item, Qt::AnchorPoint edge)
-        : m_item(item), m_edge(edge) {}
+        : m_item(item), m_edge(edge), m_type(Normal) {}
 
     AnchorVertex()
-        : m_item(0), m_edge(Qt::AnchorPoint(0)) {}
+        : 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;
 };
 
-#ifdef QT_DEBUG
-inline QString AnchorVertex::toString() const
-{
-    if (!this || !m_item) {
-        return QLatin1String("NULL");
-    }
-    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
-
 /*!
   \internal
 
@@ -150,16 +114,24 @@ struct AnchorData : public QSimplexVariable {
         Parallel
     };
 
+    enum Dependency {
+        Independent = 0,
+        Master,
+        Slave
+    };
+
     AnchorData()
         : QSimplexVariable(), from(0), to(0),
-          minSize(0), prefSize(0), expSize(0), maxSize(0),
+          minSize(0), prefSize(0), maxSize(0),
           sizeAtMinimum(0), sizeAtPreferred(0),
-          sizeAtExpanding(0), sizeAtMaximum(0),
+          sizeAtMaximum(0), item(0),
           graphicsAnchor(0), skipInPreferred(0),
-          type(Normal), hasSize(true), isLayoutAnchor(false) {}
+          type(Normal), isLayoutAnchor(false),
+          isCenterAnchor(false), orientation(0),
+          dependency(Independent) {}
 
     virtual void updateChildrenSizes() {}
-    virtual void refreshSizeHints(qreal effectiveSpacing);
+    void refreshSizeHints(const QLayoutStyleInfo *styleInfo = 0);
 
     virtual ~AnchorData() {}
 
@@ -169,50 +141,40 @@ struct AnchorData : public QSimplexVariable {
     QString name;
 #endif
 
-    inline void setFixedSize(qreal size)
-    {
-        minSize = size;
-        prefSize = size;
-        expSize = size;
-        maxSize = size;
-        sizeAtMinimum = size;
-        sizeAtPreferred = size;
-        sizeAtExpanding = size;
-        sizeAtMaximum = size;
-        hasSize = true;
-    }
-
-    inline void unsetSize()
-    {
-        hasSize = false;
-    }
-
     // Anchor is semantically directed
     AnchorVertex *from;
     AnchorVertex *to;
 
-    // Size restrictions of this edge. For anchors internal to items, these
-    // values are derived from the respective item size hints. For anchors
-    // that were added by users, these values are equal to the specified anchor
-    // size.
+    // 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 expSize;
     qreal maxSize;
 
+    // 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 sizeAtExpanding;
     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 skipInPreferred : 1;
     uint type : 2;            // either Normal, Sequential or Parallel
-    uint hasSize : 1;         // if false, get size from style.
-    uint isLayoutAnchor : 1;  // if this anchor is connected to a layout 'edge'
+    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
@@ -224,26 +186,18 @@ inline QString AnchorData::toString() const
 
 struct SequentialAnchorData : public AnchorData
 {
-    SequentialAnchorData() : 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 = QLatin1String("SequentialAnchorData");
+        name = QString::fromAscii("%1 -- %2").arg(vertices.first()->toString(), vertices.last()->toString());
 #endif
     }
 
     virtual void updateChildrenSizes();
-    virtual void refreshSizeHints(qreal effectiveSpacing);
-
-    void refreshSizeHints_helper(qreal effectiveSpacing, bool refreshChildren = true);
-
-    void setVertices(const QVector<AnchorVertex*> &vertices)
-    {
-        m_children = vertices;
-#ifdef QT_DEBUG
-        name = QString::fromAscii("%1 -- %2").arg(vertices.first()->toString(), vertices.last()->toString());
-#endif
-    }
+    void calculateSizeHints();
 
     QVector<AnchorVertex*> m_children;          // list of vertices in the sequence
     QVector<AnchorData*> m_edges;               // keep the list of edges too.
@@ -255,11 +209,13 @@ struct ParallelAnchorData : public AnchorData
         : AnchorData(), firstEdge(first), secondEdge(second)
     {
         type = AnchorData::Parallel;
+        orientation = first->orientation;
 
-        // ### Those asserts force that both child anchors have the same direction,
-        // but can't we simplify a pair of anchors in opposite directions?
-        Q_ASSERT(first->from == second->from);
-        Q_ASSERT(first->to == second->to);
+        // 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)));
+
+        // We arbitrarily choose the direction of the first child as "our" direction
         from = first->from;
         to = first->to;
 #ifdef QT_DEBUG
@@ -268,14 +224,77 @@ struct ParallelAnchorData : public AnchorData
     }
 
     virtual void updateChildrenSizes();
-    virtual void refreshSizeHints(qreal effectiveSpacing);
-
-    void refreshSizeHints_helper(qreal effectiveSpacing, bool refreshChildren = true);
+    bool calculateSizeHints();
 
     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
+
 /*!
   \internal
 
@@ -316,8 +335,17 @@ public:
     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.
+    uint reversed : 1;        // if true, the anchor was inverted to keep its value positive
 };
 
 
@@ -340,8 +368,7 @@ public:
     // Interval represents which interpolation interval are we operating in.
     enum Interval {
         MinToPreferred = 0,
-        PreferredToExpanding,
-        ExpandingToMax
+        PreferredToMax
     };
 
     // Several structures internal to the layout are duplicated to handle
@@ -413,11 +440,6 @@ public:
 
     void removeAnchor(AnchorVertex *firstVertex, AnchorVertex *secondVertex);
     void removeAnchor_helper(AnchorVertex *v1, AnchorVertex *v2);
-    void setAnchorSize(AnchorData *data, const qreal *anchorSize);
-    void anchorSize(const AnchorData *data,
-                    qreal *minSize = 0,
-                    qreal *prefSize = 0,
-                    qreal *maxSize = 0) const;
 
     void removeAnchors(QGraphicsLayoutItem *item);
 
@@ -427,20 +449,40 @@ public:
                               Qt::AnchorPoint &firstEdge,
                               QGraphicsLayoutItem *&secondItem,
                               Qt::AnchorPoint &secondEdge);
-    // for getting the actual spacing (will query the style if the
-    // spacing is not explicitly set).
-    qreal effectiveSpacing(Orientation orientation) const;
 
-    // Activation methods
-    void simplifyGraph(Orientation orientation);
-    bool simplifyGraphIteration(Orientation orientation);
-    void restoreSimplifiedGraph(Orientation orientation);
+    QLayoutStyleInfo &styleInfo() const;
+
+    AnchorData *addAnchorMaybeParallel(AnchorData *newAnchor, bool *feasible);
 
+    // Activation
     void calculateGraphs();
     void calculateGraphs(Orientation orientation);
-    void setAnchorSizeHintsFromItems(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);
@@ -456,6 +498,17 @@ public:
         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);
 
@@ -464,28 +517,23 @@ public:
 
     void calculateVertexPositions(Orientation orientation);
     void setupEdgesInterpolation(Orientation orientation);
-    void interpolateEdge(AnchorVertex *base, AnchorData *edge, Orientation orientation);
-    void interpolateSequentialEdges(AnchorVertex *base, SequentialAnchorData *edge,
-                                    Orientation orientation);
-    void interpolateParallelEdges(AnchorVertex *base, ParallelAnchorData *edge,
-                                  Orientation orientation);
+    void interpolateEdge(AnchorVertex *base, AnchorData *edge);
 
     // Linear Programming solver methods
-    bool solveMinMax(QList<QSimplexConstraint *> constraints,
+    bool solveMinMax(const QList<QSimplexConstraint *> &constraints,
                      GraphPath path, qreal *min, qreal *max);
-    bool solvePreferred(QList<QSimplexConstraint *> constraints);
-    void solveExpanding(QList<QSimplexConstraint *> constraints);
+    bool solvePreferred(const QList<QSimplexConstraint *> &constraints,
+                        const QList<AnchorData *> &variables);
     bool hasConflicts() const;
 
 #ifdef QT_DEBUG
-    void dumpGraph();
+    void dumpGraph(const QString &name = QString());
 #endif
 
 
     qreal spacings[NOrientations];
     // Size hints from simplex engine
     qreal sizeHints[2][3];
-    qreal sizeAtExpanding[2];
 
     // Items
     QVector<QGraphicsLayoutItem *> items;
@@ -498,6 +546,14 @@ public:
     // 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];
@@ -508,14 +564,21 @@ public:
     Interval interpolationInterval[2];
     qreal interpolationProgress[2];
 
-    // ###
-    bool graphSimplified[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
diff --git a/src/gui/graphicsview/qgraphicsgridlayout.cpp b/src/gui/graphicsview/qgraphicsgridlayout.cpp
index d1d91db..9a8dba0 100644
--- a/src/gui/graphicsview/qgraphicsgridlayout.cpp
+++ b/src/gui/graphicsview/qgraphicsgridlayout.cpp
@@ -63,7 +63,7 @@
     You can access each item in the layout by calling count() and itemAt(). Calling
     removeAt() will remove an item from the layout, without
     destroying it.
-    
+
     \sa QGraphicsLinearLayout, QGraphicsWidget
 */
 
@@ -89,7 +89,7 @@ public:
     QLayoutStyleInfo styleInfo() const;
 
     QGridLayoutEngine engine;
-#ifdef QT_DEBUG    
+#ifdef QT_DEBUG
     void dump(int indent) const;
 #endif
 };
@@ -121,7 +121,7 @@ QGraphicsGridLayout::~QGraphicsGridLayout()
     for (int i = count() - 1; i >= 0; --i) {
         QGraphicsLayoutItem *item = itemAt(i);
         // The following lines can be removed, but this removes the item
-        // from the layout more efficiently than the implementation of 
+        // from the layout more efficiently than the implementation of
         // ~QGraphicsLayoutItem.
         removeAt(i);
         if (item) {
@@ -141,18 +141,22 @@ void QGraphicsGridLayout::addItem(QGraphicsLayoutItem *item, int row, int column
 {
     Q_D(QGraphicsGridLayout);
     if (row < 0 || column < 0) {
-	qWarning("QGraphicsGridLayout::addItem: invalid row/column: %d",
-		 row < 0 ? row : column);
-	return;
+        qWarning("QGraphicsGridLayout::addItem: invalid row/column: %d",
+                 row < 0 ? row : column);
+        return;
     }
     if (columnSpan < 1 || rowSpan < 1) {
-	qWarning("QGraphicsGridLayout::addItem: invalid row span/column span: %d",
-		 rowSpan < 1 ? rowSpan : columnSpan);
-	return;
+        qWarning("QGraphicsGridLayout::addItem: invalid row span/column span: %d",
+                 rowSpan < 1 ? rowSpan : columnSpan);
+        return;
     }
     if (!item) {
-	qWarning("QGraphicsGridLayout::addItem: cannot add null item");
-	return;
+        qWarning("QGraphicsGridLayout::addItem: cannot add null item");
+        return;
+    }
+    if (item == this) {
+        qWarning("QGraphicsGridLayout::addItem: cannot insert itself");
+        return;
     }
 
     d->addChildLayoutItem(item);
@@ -647,5 +651,5 @@ QSizePolicy::ControlTypes QGraphicsGridLayout::controlTypes(LayoutSide side) con
 #endif
 
 QT_END_NAMESPACE
-        
-#endif //QT_NO_GRAPHICSVIEW        
+
+#endif //QT_NO_GRAPHICSVIEW
diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index 45627f6..3f6dff2 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -386,6 +386,12 @@
     introduced in Qt 4.6.
 
     \omitvalue ItemIsFocusScope Internal only (for now).
+
+    \value ItemSendsScenePositionChanges The item enables itemChange()
+    notifications for ItemScenePositionHasChanged. For performance reasons,
+    these notifications are disabled by default. You must enable this flag
+    to receive notifications for scene position changes. This flag was
+    introduced in Qt 4.6.
 */
 
 /*!
@@ -562,6 +568,14 @@
     \value ItemOpacityHasChanged The item's opacity has changed. The value
     argument is the new opacity (i.e., a double). Do not call setOpacity() as
     this notification is delivered. The return value is ignored.
+
+    \value ItemScenePositionHasChanged The item's scene position has changed.
+    This notification is sent if the ItemSendsScenePositionChanges flag is
+    enabled, and after the item's scene position has changed (i.e., the
+    position or transformation of the item itself or the position or
+    transformation of any ancestor has changed). The value argument is the
+    new scene position (the same as scenePos()), and QGraphicsItem ignores
+    the return value for this notification (i.e., a read-only notification).
 */
 
 /*!
@@ -990,6 +1004,10 @@ void QGraphicsItemPrivate::setParentItemHelper(QGraphicsItem *newParent)
     if (scene) {
         // Deliver the change to the index
         scene->d_func()->index->itemChange(q, QGraphicsItem::ItemParentChange, newParentVariant);
+
+        // Disable scene pos notifications for old ancestors
+        if (scenePosDescendants || (flags & QGraphicsItem::ItemSendsScenePositionChanges))
+            scene->d_func()->setScenePosItemEnabled(q, false);
     }
 
     if (subFocusItem && parent) {
@@ -1039,13 +1057,31 @@ void QGraphicsItemPrivate::setParentItemHelper(QGraphicsItem *newParent)
     }
 
     // Update focus scope item ptr in new scope.
-    if (newParent) {
+    QGraphicsItem *newFocusScopeItem = subFocusItem ? subFocusItem : parentFocusScopeItem;
+    if (newFocusScopeItem && newParent) {
+        if (subFocusItem) {
+            // Find the subFocusItem's topmost focus scope.
+            QGraphicsItem *ancestorScope = 0;
+            QGraphicsItem *p = subFocusItem->d_ptr->parent;
+            while (p) {
+                if (p->flags() & QGraphicsItem::ItemIsFocusScope)
+                    ancestorScope = p;
+                if (p->isPanel())
+                    break;
+                p = p->parentItem();
+            }
+            if (ancestorScope)
+                newFocusScopeItem = ancestorScope;
+        }
+
         QGraphicsItem *p = newParent;
         while (p) {
             if (p->flags() & QGraphicsItem::ItemIsFocusScope) {
-                p->d_ptr->focusScopeItem = subFocusItem ? subFocusItem : parentFocusScopeItem;
-                // ### The below line might not make sense...
-                if (subFocusItem)
+                p->d_ptr->focusScopeItem = newFocusScopeItem;
+                // Ensure the new item is no longer the subFocusItem. The
+                // only way to set focus on a child of a focus scope is
+                // by setting focus on the scope itself.
+                if (subFocusItem && !p->focusItem())
                     subFocusItem->d_ptr->clearSubFocus();
                 break;
             }
@@ -1066,10 +1102,15 @@ void QGraphicsItemPrivate::setParentItemHelper(QGraphicsItem *newParent)
 
         parent->d_ptr->addChild(q);
         parent->itemChange(QGraphicsItem::ItemChildAddedChange, thisPointerVariant);
-        if (!implicitUpdate && scene) {
-            scene->d_func()->markDirty(q_ptr, QRect(),
-                                       /*invalidateChildren=*/false,
-                                       /*maybeDirtyClipPath=*/true);
+        if (scene) {
+            if (!implicitUpdate)
+                scene->d_func()->markDirty(q_ptr, QRect(),
+                                           /*invalidateChildren=*/false,
+                                           /*maybeDirtyClipPath=*/true);
+
+            // Re-enable scene pos notifications for new ancestors
+            if (scenePosDescendants || (flags & QGraphicsItem::ItemSendsScenePositionChanges))
+                scene->d_func()->setScenePosItemEnabled(q, true);
         }
 
         // Inherit ancestor flags from the new parent.
@@ -1228,7 +1269,8 @@ void QGraphicsItemCache::purge()
 }
 
 /*!
-    Constructs a QGraphicsItem with the given \a parent.
+    Constructs a QGraphicsItem with the given \a parent item.
+    It does not modify the parent object returned by QObject::parent().
 
     If \a parent is 0, you can add the item to a scene by calling
     QGraphicsScene::addItem(). The item will then become a top-level item.
@@ -1286,6 +1328,8 @@ QGraphicsItem::QGraphicsItem(QGraphicsItemPrivate &dd, QGraphicsItem *parent,
 */
 QGraphicsItem::~QGraphicsItem()
 {
+    if (d_ptr->isObject)
+        QObjectPrivate::get(static_cast<QGraphicsObject *>(this))->wasDeleted = true;
     d_ptr->inDestructor = 1;
     d_ptr->removeExtraItemCache();
 
@@ -1315,7 +1359,9 @@ QGraphicsItem::~QGraphicsItem()
         d_ptr->setParentItemHelper(0);
     }
 
+#ifndef QT_NO_GRAPHICSEFFECT
     delete d_ptr->graphicsEffect;
+#endif //QT_NO_GRAPHICSEFFECT
     if (d_ptr->transformData) {
         for(int i = 0; i < d_ptr->transformData->graphicsTransforms.size(); ++i) {
             QGraphicsTransform *t = d_ptr->transformData->graphicsTransforms.at(i);
@@ -1511,6 +1557,8 @@ const QGraphicsObject *QGraphicsItem::toGraphicsObject() const
     the parent. You should not \l{QGraphicsScene::addItem()}{add} the
     item to the scene yourself.
 
+    Calling this function on an item that is an ancestor of \a parent have undefined behaviour.
+
     \sa parentItem(), childItems()
 */
 void QGraphicsItem::setParentItem(QGraphicsItem *parent)
@@ -1655,7 +1703,7 @@ void QGraphicsItem::setFlags(GraphicsItemFlags flags)
         d_ptr->scene->d_func()->index->itemChange(this, ItemFlagsChange, quint32(flags));
 
     // Flags that alter the geometry of the item (or its children).
-    const quint32 geomChangeFlagsMask = (ItemClipsChildrenToShape | ItemClipsToShape | ItemIgnoresTransformations);
+    const quint32 geomChangeFlagsMask = (ItemClipsChildrenToShape | ItemClipsToShape | ItemIgnoresTransformations | ItemIsSelectable);
     bool fullUpdate = (quint32(flags) & geomChangeFlagsMask) != (d_ptr->flags & geomChangeFlagsMask);
     if (fullUpdate)
         d_ptr->paintedViewBoundingRectsNeedRepaint = 1;
@@ -1723,6 +1771,12 @@ void QGraphicsItem::setFlags(GraphicsItemFlags flags)
     }
 
     if (d_ptr->scene) {
+        if ((flags & ItemSendsScenePositionChanges) != (oldFlags & ItemSendsScenePositionChanges)) {
+            if (flags & ItemSendsScenePositionChanges)
+                d_ptr->scene->d_func()->registerScenePosItem(this);
+            else
+                d_ptr->scene->d_func()->unregisterScenePosItem(this);
+        }
         d_ptr->scene->d_func()->markDirty(this, QRectF(),
                                           /*invalidateChildren=*/true,
                                           /*maybeDirtyClipPath*/true);
@@ -2482,12 +2536,16 @@ void QGraphicsItem::setOpacity(qreal opacity)
     itemChange(ItemOpacityHasChanged, newOpacityVariant);
 
     // Update.
-    if (d_ptr->scene)
+    if (d_ptr->scene) {
+#ifndef QT_NO_GRAPHICSEFFECT
+        d_ptr->invalidateGraphicsEffectsRecursively();
+#endif //QT_NO_GRAPHICSEFFECT
         d_ptr->scene->d_func()->markDirty(this, QRectF(),
                                           /*invalidateChildren=*/true,
                                           /*maybeDirtyClipPath=*/false,
                                           /*force=*/false,
                                           /*ignoreOpacity=*/true);
+    }
 
     if (d_ptr->isObject)
         emit static_cast<QGraphicsObject *>(this)->opacityChanged();
@@ -2498,6 +2556,7 @@ void QGraphicsItem::setOpacity(qreal opacity)
 
     \since 4.6
 */
+#ifndef QT_NO_GRAPHICSEFFECT
 QGraphicsEffect *QGraphicsItem::graphicsEffect() const
 {
     return d_ptr->graphicsEffect;
@@ -2544,6 +2603,7 @@ void QGraphicsItem::setGraphicsEffect(QGraphicsEffect *effect)
 
     prepareGeometryChange();
 }
+#endif //QT_NO_GRAPHICSEFFECT
 
 /*!
     \internal
@@ -2557,6 +2617,7 @@ void QGraphicsItem::setGraphicsEffect(QGraphicsEffect *effect)
 */
 QRectF QGraphicsItemPrivate::effectiveBoundingRect() const
 {
+#ifndef QT_NO_GRAPHICSEFFECT
     QGraphicsEffect *effect = graphicsEffect;
     QRectF brect = effect && effect->isEnabled() ? effect->boundingRect() : q_ptr->boundingRect();
     if (ancestorFlags & QGraphicsItemPrivate::AncestorClipsChildren)
@@ -2573,6 +2634,10 @@ QRectF QGraphicsItemPrivate::effectiveBoundingRect() const
     }
 
     return brect;
+#else //QT_NO_GRAPHICSEFFECT
+    return q_ptr->boundingRect();
+#endif //QT_NO_GRAPHICSEFFECT
+
 }
 
 /*!
@@ -2926,7 +2991,7 @@ bool QGraphicsItem::hasFocus() const
 {
     if (d_ptr->focusProxy)
         return d_ptr->focusProxy->hasFocus();
-    return (d_ptr->scene && d_ptr->scene->focusItem() == this);
+    return isActive() && (d_ptr->scene && d_ptr->scene->focusItem() == this);
 }
 
 /*!
@@ -2977,8 +3042,11 @@ void QGraphicsItemPrivate::setFocusHelper(Qt::FocusReason focusReason, bool clim
     while (p) {
         if (p->flags() & QGraphicsItem::ItemIsFocusScope) {
             p->d_ptr->focusScopeItem = q_ptr;
-            if (!q_ptr->isActive() || !p->focusItem())
+            if (!p->focusItem()) {
+                // If you call setFocus on a child of a focus scope that
+                // doesn't currently have a focus item, then stop.
                 return;
+            }
             break;
         }
         p = p->d_ptr->parent;
@@ -3281,6 +3349,9 @@ QPointF QGraphicsItem::pos() const
 */
 void QGraphicsItem::setX(qreal x)
 {
+    if (d_ptr->inDestructor)
+        return;
+
     d_ptr->setPosHelper(QPointF(x, d_ptr->pos.y()));
 }
 
@@ -3302,6 +3373,9 @@ void QGraphicsItem::setX(qreal x)
 */
 void QGraphicsItem::setY(qreal y)
 {
+    if (d_ptr->inDestructor)
+        return;
+
     d_ptr->setPosHelper(QPointF(d_ptr->pos.x(), y));
 }
 
@@ -3367,6 +3441,9 @@ void QGraphicsItem::setPos(const QPointF &pos)
     if (d_ptr->pos == pos)
         return;
 
+    if (d_ptr->inDestructor)
+        return;
+
     // Update and repositition.
     if (!(d_ptr->flags & ItemSendsGeometryChanges)) {
         d_ptr->setPosHelper(pos);
@@ -3384,6 +3461,7 @@ void QGraphicsItem::setPos(const QPointF &pos)
 
     // Send post-notification.
     itemChange(QGraphicsItem::ItemPositionHasChanged, newPosVariant);
+    d_ptr->sendScenePosChange();
 }
 
 /*!
@@ -3994,6 +4072,7 @@ void QGraphicsItem::setTransform(const QTransform &matrix, bool combine)
 
     // Send post-notification.
     itemChange(ItemTransformHasChanged, newTransformVariant);
+    d_ptr->sendScenePosChange();
 }
 
 /*!
@@ -4218,6 +4297,24 @@ void QGraphicsItemPrivate::ensureSequentialSiblingIndex()
 }
 
 /*!
+    \internal
+*/
+inline void QGraphicsItemPrivate::sendScenePosChange()
+{
+    Q_Q(QGraphicsItem);
+    if (scene) {
+        if (flags & QGraphicsItem::ItemSendsScenePositionChanges)
+            q->itemChange(QGraphicsItem::ItemScenePositionHasChanged, q->scenePos());
+        if (scenePosDescendants) {
+            foreach (QGraphicsItem *item, scene->d_func()->scenePosItems) {
+                if (q->isAncestorOf(item))
+                    item->itemChange(QGraphicsItem::ItemScenePositionHasChanged, item->scenePos());
+            }
+        }
+    }
+}
+
+/*!
     \since 4.6
 
     Stacks this item before \a sibling, which must be a sibling item (i.e., the
@@ -4259,7 +4356,7 @@ void QGraphicsItem::stackBefore(const QGraphicsItem *sibling)
     // Only move items with the same Z value, and that need moving.
     int siblingIndex = sibling->d_ptr->siblingIndex;
     int myIndex = d_ptr->siblingIndex;
-    if (myIndex >= siblingIndex && d_ptr->z == sibling->d_ptr->z) {
+    if (myIndex >= siblingIndex) {
         siblings->move(myIndex, siblingIndex);
         // Fixup the insertion ordering.
         for (int i = 0; i < siblings->size(); ++i) {
@@ -4268,6 +4365,12 @@ void QGraphicsItem::stackBefore(const QGraphicsItem *sibling)
                 ++index;
         }
         d_ptr->siblingIndex = siblingIndex;
+        for (int i = 0; i < siblings->size(); ++i) {
+            int &index = siblings->at(i)->d_ptr->siblingIndex;
+            if (i != siblingIndex && index >= siblingIndex && index <= myIndex)
+                siblings->at(i)->d_ptr->siblingOrderChange();
+        }
+        d_ptr->siblingOrderChange();
     }
 }
 
@@ -4735,7 +4838,7 @@ bool QGraphicsItem::isObscuredBy(const QGraphicsItem *item) const
 {
     if (!item)
         return false;
-    return QGraphicsSceneBspTreeIndexPrivate::closestItemFirst_withoutCache(item, this)
+    return qt_closestItemFirst(item, this)
         && qt_QGraphicsItem_isObscured(this, item, boundingRect());
 }
 
@@ -4949,6 +5052,24 @@ int QGraphicsItemPrivate::depth() const
 /*!
     \internal
 */
+#ifndef QT_NO_GRAPHICSEFFECT
+void QGraphicsItemPrivate::invalidateGraphicsEffectsRecursively()
+{
+    QGraphicsItemPrivate *itemPrivate = this;
+    do {
+        if (itemPrivate->graphicsEffect) {
+            itemPrivate->notifyInvalidated = 1;
+
+            if (!itemPrivate->updateDueToGraphicsEffect)
+                static_cast<QGraphicsItemEffectSourcePrivate *>(itemPrivate->graphicsEffect->d_func()->source->d_func())->invalidateCache();
+        }
+    } while ((itemPrivate = itemPrivate->parent ? itemPrivate->parent->d_ptr.data() : 0));
+}
+#endif //QT_NO_GRAPHICSEFFECT
+
+/*!
+    \internal
+*/
 void QGraphicsItemPrivate::invalidateDepthRecursively()
 {
     if (itemDepth == -1)
@@ -5249,6 +5370,16 @@ void QGraphicsItemPrivate::subFocusItemChange()
 /*!
     \internal
 
+    Subclasses can reimplement this function to be notified when its
+    siblingIndex order is changed.
+*/
+void QGraphicsItemPrivate::siblingOrderChange()
+{
+}
+
+/*!
+    \internal
+
     Tells us if it is a proxy widget
 */
 bool QGraphicsItemPrivate::isProxyWidget() const
@@ -5280,11 +5411,9 @@ void QGraphicsItem::update(const QRectF &rect)
         return;
 
     // Make sure we notify effects about invalidated source.
-    QGraphicsItem *item = this;
-    do {
-        if (item->d_ptr->graphicsEffect)
-            item->d_ptr->notifyInvalidated = 1;
-    } while ((item = item->d_ptr->parent));
+#ifndef QT_NO_GRAPHICSEFFECT
+    d_ptr->invalidateGraphicsEffectsRecursively();
+#endif //QT_NO_GRAPHICSEFFECT
 
     if (CacheMode(d_ptr->cacheMode) != NoCache) {
         // Invalidate cache.
@@ -7267,6 +7396,21 @@ static void qt_graphicsItem_highlightSelected(
     The class extends a QGraphicsItem with QObject's signal/slot and property mechanisms.
     It maps many of QGraphicsItem's basic setters and getters to properties and adds notification
     signals for many of them.
+
+    \section1 Parents and Children
+
+    Each graphics object can be constructed with a parent item. This ensures that the
+    item will be destroyed when its parent item is destroyed. Although QGraphicsObject
+    inherits from both QObject and QGraphicsItem, you should use the functions provided
+    by QGraphicsItem, \e not QObject, to manage the relationships between parent and
+    child items.
+
+    The relationships between items can be explored using the parentItem() and childItems()
+    functions. In the hierarchy of items in a scene, the parentObject() and parentWidget()
+    functions are the equivalent of the QWidget::parent() and QWidget::parentWidget()
+    functions for QWidget subclasses.
+
+    \sa QGraphicsWidget
 */
 
 /*!
@@ -7288,22 +7432,38 @@ QGraphicsObject::QGraphicsObject(QGraphicsItemPrivate &dd, QGraphicsItem *parent
 }
 
 /*!
-    Subscribes the graphics object to the given \a gesture for the specified \a context.
+    Subscribes the graphics object to the given \a gesture with specific \a flags.
 
-    \sa QGestureEvent
+    \sa ungrabGesture(), QGestureEvent
 */
-
-void QGraphicsObject::grabGesture(Qt::GestureType gesture, Qt::GestureContext context)
+void QGraphicsObject::grabGesture(Qt::GestureType gesture, Qt::GestureFlags flags)
 {
     QGraphicsItemPrivate * const d = QGraphicsItem::d_func();
-    d->gestureContext.insert(gesture, context);
+    d->gestureContext.insert(gesture, flags);
     (void)QGestureManager::instance(); // create a gesture manager
 }
 
 /*!
+    Unsubscribes the graphics object from the given \a gesture.
+
+    \sa grabGesture(), QGestureEvent
+*/
+void QGraphicsObject::ungrabGesture(Qt::GestureType gesture)
+{
+    QGraphicsItemPrivate * const d = QGraphicsItem::d_func();
+    if (d->gestureContext.remove(gesture)) {
+        QGestureManager *manager = QGestureManager::instance();
+        manager->cleanupCachedGestures(this, gesture);
+    }
+}
+
+/*!
   \property QGraphicsObject::parent
   \brief the parent of the item
 
+  \note The item's parent is set independently of the parent object returned
+  by QObject::parent().
+
   \sa QGraphicsItem::setParentItem(), QGraphicsItem::parentObject()
 */
 
@@ -9122,10 +9282,14 @@ void QGraphicsPixmapItem::setOffset(const QPointF &offset)
 QRectF QGraphicsPixmapItem::boundingRect() const
 {
     Q_D(const QGraphicsPixmapItem);
-    qreal pw = 1.0;
     if (d->pixmap.isNull())
         return QRectF();
-    return QRectF(d->offset, d->pixmap.size()).adjusted(-pw/2, -pw/2, pw/2, pw/2);
+    if (d->flags & ItemIsSelectable) {
+        qreal pw = 1.0;
+        return QRectF(d->offset, d->pixmap.size()).adjusted(-pw/2, -pw/2, pw/2, pw/2);
+    } else {
+        return QRectF(d->offset, d->pixmap.size());
+    }
 }
 
 /*!
@@ -9442,6 +9606,7 @@ void QGraphicsTextItem::setDefaultTextColor(const QColor &col)
     QPalette pal = c->palette();
     pal.setColor(QPalette::Text, col);
     c->setPalette(pal);
+    update();
 }
 
 /*!
@@ -9635,12 +9800,14 @@ bool QGraphicsTextItem::sceneEvent(QEvent *event)
         // Reset the focus widget's input context, regardless
         // of how this item gained or lost focus.
         if (QWidget *fw = qApp->focusWidget()) {
+#ifndef QT_NO_IM
             if (QInputContext *qic = fw->inputContext()) {
                 if (event->type() == QEvent::FocusIn || event->type() == QEvent::FocusOut)
                     qic->reset();
                 else
                     qic->update();
             }
+#endif //QT_NO_IM
         }
         break;
     default:
@@ -10011,9 +10178,10 @@ bool QGraphicsTextItemPrivate::_q_mouseOnEdge(QGraphicsSceneMouseEvent *event)
 void QGraphicsTextItem::setTextInteractionFlags(Qt::TextInteractionFlags flags)
 {
     if (flags == Qt::NoTextInteraction)
-        setFlags(this->flags() & ~QGraphicsItem::ItemIsFocusable);
+        setFlags(this->flags() & ~(QGraphicsItem::ItemIsFocusable | QGraphicsItem::ItemAcceptsInputMethod));
     else
-        setFlags(this->flags() | QGraphicsItem::ItemIsFocusable);
+        setFlags(this->flags() | QGraphicsItem::ItemIsFocusable | QGraphicsItem::ItemAcceptsInputMethod);
+
     dd->textControl()->setTextInteractionFlags(flags);
 }
 
@@ -10601,6 +10769,7 @@ int QGraphicsItemGroup::type() const
     return Type;
 }
 
+#ifndef QT_NO_GRAPHICSEFFECT
 QRectF QGraphicsItemEffectSourcePrivate::boundingRect(Qt::CoordinateSystem system) const
 {
     const bool deviceCoordinates = (system == Qt::DeviceCoordinates);
@@ -10644,7 +10813,8 @@ void QGraphicsItemEffectSourcePrivate::draw(QPainter *painter)
     }
 }
 
-QPixmap QGraphicsItemEffectSourcePrivate::pixmap(Qt::CoordinateSystem system, QPoint *offset) const
+QPixmap QGraphicsItemEffectSourcePrivate::pixmap(Qt::CoordinateSystem system, QPoint *offset,
+                                                 QGraphicsEffect::PixmapPadMode mode) const
 {
     const bool deviceCoordinates = (system == Qt::DeviceCoordinates);
     if (!info && deviceCoordinates) {
@@ -10658,7 +10828,17 @@ QPixmap QGraphicsItemEffectSourcePrivate::pixmap(Qt::CoordinateSystem system, QP
     QGraphicsScenePrivate *scened = item->d_ptr->scene->d_func();
 
     const QRectF sourceRect = boundingRect(system);
-    QRect effectRect = item->graphicsEffect()->boundingRectFor(sourceRect).toAlignedRect();
+    QRect effectRect;
+
+    if (mode == QGraphicsEffect::PadToEffectiveBoundingRect) {
+        effectRect = item->graphicsEffect()->boundingRectFor(sourceRect).toAlignedRect();
+    } else if (mode == QGraphicsEffect::PadToTransparentBorder) {
+        // adjust by 1.5 to account for cosmetic pens
+        effectRect = sourceRect.adjusted(-1.5, -1.5, 1.5, 1.5).toAlignedRect();
+    } else {
+        effectRect = sourceRect.toAlignedRect();
+    }
+
     if (offset)
         *offset = effectRect.topLeft();
 
@@ -10686,10 +10866,15 @@ QPixmap QGraphicsItemEffectSourcePrivate::pixmap(Qt::CoordinateSystem system, QP
             effectRect.setBottom(deviceHeight -1);
 
     }
-
     if (effectRect.isEmpty())
         return QPixmap();
 
+    if (system == Qt::LogicalCoordinates
+        && effectRect.size() == sourceRect.size()
+        && isPixmap()) {
+        return static_cast<QGraphicsPixmapItem *>(item)->pixmap();
+    }
+
     QPixmap pixmap(effectRect.size());
     pixmap.fill(Qt::transparent);
     QPainter pixmapPainter(&pixmap);
@@ -10721,8 +10906,10 @@ QPixmap QGraphicsItemEffectSourcePrivate::pixmap(Qt::CoordinateSystem system, QP
     }
 
     pixmapPainter.end();
+
     return pixmap;
 }
+#endif //QT_NO_GRAPHICSEFFECT
 
 #ifndef QT_NO_DEBUG_STREAM
 QDebug operator<<(QDebug debug, QGraphicsItem *item)
@@ -10732,14 +10919,35 @@ QDebug operator<<(QDebug debug, QGraphicsItem *item)
         return debug;
     }
 
-    debug << "QGraphicsItem(this =" << ((void*)item)
-          << ", parent =" << ((void*)item->parentItem())
+    if (QGraphicsObject *o = item->toGraphicsObject())
+        debug << o->metaObject()->className();
+    else
+        debug << "QGraphicsItem";
+    debug << "(this =" << (void*)item
+          << ", parent =" << (void*)item->parentItem()
           << ", pos =" << item->pos()
           << ", z =" << item->zValue() << ", flags = "
           << item->flags() << ")";
     return debug;
 }
 
+QDebug operator<<(QDebug debug, QGraphicsObject *item)
+{
+    if (!item) {
+        debug << "QGraphicsObject(0)";
+        return debug;
+    }
+
+    debug.nospace() << item->metaObject()->className() << '(' << (void*)item;
+    if (!item->objectName().isEmpty())
+        debug << ", name = " << item->objectName();
+    debug.nospace() << ", parent = " << ((void*)item->parentItem())
+          << ", pos = " << item->pos()
+          << ", z = " << item->zValue() << ", flags = "
+          << item->flags() << ')';
+    return debug.space();
+}
+
 QDebug operator<<(QDebug debug, QGraphicsItem::GraphicsItemChange change)
 {
     const char *str = "UnknownChange";
@@ -10825,6 +11033,9 @@ QDebug operator<<(QDebug debug, QGraphicsItem::GraphicsItemChange change)
     case QGraphicsItem::ItemOpacityHasChanged:
         str = "ItemOpacityHasChanged";
         break;
+    case QGraphicsItem::ItemScenePositionHasChanged:
+        str = "ItemScenePositionHasChanged";
+        break;
     }
     debug << str;
     return debug;
@@ -10882,6 +11093,9 @@ QDebug operator<<(QDebug debug, QGraphicsItem::GraphicsItemFlag flag)
     case QGraphicsItem::ItemIsFocusScope:
         str = "ItemIsFocusScope";
         break;
+    case QGraphicsItem::ItemSendsScenePositionChanges:
+        str = "ItemSendsScenePositionChanges";
+        break;
     }
     debug << str;
     return debug;
diff --git a/src/gui/graphicsview/qgraphicsitem.h b/src/gui/graphicsview/qgraphicsitem.h
index 2665235..8bbe9f1 100644
--- a/src/gui/graphicsview/qgraphicsitem.h
+++ b/src/gui/graphicsview/qgraphicsitem.h
@@ -105,7 +105,8 @@ public:
         ItemAcceptsInputMethod = 0x1000,
         ItemNegativeZStacksBehindParent = 0x2000,
         ItemIsPanel = 0x4000,
-        ItemIsFocusScope = 0x8000 // internal
+        ItemIsFocusScope = 0x8000, // internal
+        ItemSendsScenePositionChanges = 0x10000
         // NB! Don't forget to increase the d_ptr->flags bit field by 1 when adding a new flag.
     };
     Q_DECLARE_FLAGS(GraphicsItemFlags, GraphicsItemFlag)
@@ -137,7 +138,8 @@ public:
         ItemZValueChange,
         ItemZValueHasChanged,
         ItemOpacityChange,
-        ItemOpacityHasChanged
+        ItemOpacityHasChanged,
+        ItemScenePositionHasChanged
     };
 
     enum CacheMode {
@@ -225,9 +227,11 @@ public:
     qreal effectiveOpacity() const;
     void setOpacity(qreal opacity);
 
+#ifndef QT_NO_GRAPHICSEFFECT
     // Effect
     QGraphicsEffect *graphicsEffect() const;
     void setGraphicsEffect(QGraphicsEffect *effect);
+#endif //QT_NO_GRAPHICSEFFECT
 
     Qt::MouseButtons acceptedMouseButtons() const;
     void setAcceptedMouseButtons(Qt::MouseButtons buttons);
@@ -555,7 +559,8 @@ public:
     using QObject::children;
 #endif
 
-    void grabGesture(Qt::GestureType type, Qt::GestureContext context = Qt::WidgetWithChildrenGesture);
+    void grabGesture(Qt::GestureType type, Qt::GestureFlags flags = Qt::GestureFlags());
+    void ungrabGesture(Qt::GestureType type);
 
 Q_SIGNALS:
     void parentChanged();
@@ -1120,6 +1125,7 @@ template <class T> inline T qgraphicsitem_cast(const QGraphicsItem *item)
 
 #ifndef QT_NO_DEBUG_STREAM
 Q_GUI_EXPORT QDebug operator<<(QDebug debug, QGraphicsItem *item);
+Q_GUI_EXPORT QDebug operator<<(QDebug debug, QGraphicsObject *item);
 Q_GUI_EXPORT QDebug operator<<(QDebug debug, QGraphicsItem::GraphicsItemChange change);
 Q_GUI_EXPORT QDebug operator<<(QDebug debug, QGraphicsItem::GraphicsItemFlag flag);
 Q_GUI_EXPORT QDebug operator<<(QDebug debug, QGraphicsItem::GraphicsItemFlags flags);
diff --git a/src/gui/graphicsview/qgraphicsitem_p.h b/src/gui/graphicsview/qgraphicsitem_p.h
index 6550362..75c8246 100644
--- a/src/gui/graphicsview/qgraphicsitem_p.h
+++ b/src/gui/graphicsview/qgraphicsitem_p.h
@@ -61,6 +61,7 @@
 #include <private/qgraphicstransform_p.h>
 
 #include <private/qgraphicseffect_p.h>
+#include <qgraphicseffect.h>
 
 #include <QtCore/qpoint.h>
 
@@ -177,6 +178,8 @@ public:
         wantsActive(0),
         holesInSiblingIndex(0),
         sequentialOrdering(1),
+        updateDueToGraphicsEffect(0),
+        scenePosDescendants(0),
         globalStackingOrder(-1),
         q_ptr(0)
     {
@@ -221,6 +224,9 @@ public:
     bool discardUpdateRequest(bool ignoreClipping = false, bool ignoreVisibleBit = false,
                               bool ignoreDirtyBit = false, bool ignoreOpacity = false) const;
     int depth() const;
+#ifndef QT_NO_GRAPHICSEFFECT
+    void invalidateGraphicsEffectsRecursively();
+#endif //QT_NO_GRAPHICSEFFECT
     void invalidateDepthRecursively();
     void resolveDepth();
     void addChild(QGraphicsItem *child);
@@ -426,6 +432,8 @@ public:
     inline void ensureSortedChildren();
     static inline bool insertionOrder(QGraphicsItem *a, QGraphicsItem *b);
     void ensureSequentialSiblingIndex();
+    inline void sendScenePosChange();
+    virtual void siblingOrderChange();
 
     QPainterPath cachedClipPath;
     QRectF childrenBoundingRect;
@@ -450,7 +458,7 @@ public:
     QGraphicsItem *focusScopeItem;
     Qt::InputMethodHints imHints;
     QGraphicsItem::PanelModality panelModality;
-    QMap<Qt::GestureType, Qt::GestureContext> gestureContext;
+    QMap<Qt::GestureType, Qt::GestureFlags> gestureContext;
 
     // Packed 32 bits
     quint32 acceptedMouseButtons : 5;
@@ -480,7 +488,7 @@ public:
 
     // Packed 32 bits
     quint32 fullUpdatePending : 1;
-    quint32 flags : 16;
+    quint32 flags : 17;
     quint32 dirtyChildrenBoundingRect : 1;
     quint32 paintedViewBoundingRectsNeedRepaint : 1;
     quint32 dirtySceneTransform : 1;
@@ -495,13 +503,15 @@ public:
     quint32 sceneTransformTranslateOnly : 1;
     quint32 notifyBoundingRectChanged : 1;
     quint32 notifyInvalidated : 1;
-    quint32 mouseSetsFocus : 1;
 
     // New 32 bits
+    quint32 mouseSetsFocus : 1;
     quint32 explicitActivate : 1;
     quint32 wantsActive : 1;
     quint32 holesInSiblingIndex : 1;
     quint32 sequentialOrdering : 1;
+    quint32 updateDueToGraphicsEffect : 1;
+    quint32 scenePosDescendants : 1;
 
     // Optional stacking order
     int globalStackingOrder;
@@ -573,6 +583,7 @@ struct QGraphicsItemPaintInfo
     quint32 drawItem : 1;
 };
 
+#ifndef QT_NO_GRAPHICSEFFECT
 class QGraphicsItemEffectSourcePrivate : public QGraphicsEffectSourcePrivate
 {
 public:
@@ -589,16 +600,21 @@ public:
     inline const QWidget *widget() const
     { return 0; }
 
-    inline void update()
-    { item->update(); }
+    inline void update() {
+        item->d_ptr->updateDueToGraphicsEffect = true;
+        item->update();
+        item->d_ptr->updateDueToGraphicsEffect = false;
+    }
 
     inline void effectBoundingRectChanged()
     { item->prepareGeometryChange(); }
 
     inline bool isPixmap() const
     {
-        return (item->type() == QGraphicsPixmapItem::Type);
-            //|| (item->d_ptr->isObject && qobject_cast<QFxImage *>(q_func()));
+        return item->type() == QGraphicsPixmapItem::Type
+               && !(item->flags() & QGraphicsItem::ItemIsSelectable)
+               && item->d_ptr->children.size() == 0;
+            //|| (item->d_ptr->isObject && qobject_cast<QmlGraphicsImage *>(q_func()));
     }
 
     inline const QStyleOption *styleOption() const
@@ -615,12 +631,80 @@ public:
 
     QRectF boundingRect(Qt::CoordinateSystem system) const;
     void draw(QPainter *);
-    QPixmap pixmap(Qt::CoordinateSystem system, QPoint *offset) const;
+    QPixmap pixmap(Qt::CoordinateSystem system,
+                   QPoint *offset,
+                   QGraphicsEffect::PixmapPadMode mode) const;
 
     QGraphicsItem *item;
     QGraphicsItemPaintInfo *info;
+    QTransform lastEffectTransform;
 };
+#endif //QT_NO_GRAPHICSEFFECT
 
+/*!
+    Returns true if \a item1 is on top of \a item2.
+    The items dont need to be siblings.
+
+    \internal
+*/
+inline bool qt_closestItemFirst(const QGraphicsItem *item1, const QGraphicsItem *item2)
+{
+    // Siblings? Just check their z-values.
+    const QGraphicsItemPrivate *d1 = item1->d_ptr.data();
+    const QGraphicsItemPrivate *d2 = item2->d_ptr.data();
+    if (d1->parent == d2->parent)
+        return qt_closestLeaf(item1, item2);
+
+    // Find common ancestor, and each item's ancestor closest to the common
+    // ancestor.
+    int item1Depth = d1->depth();
+    int item2Depth = d2->depth();
+    const QGraphicsItem *p = item1;
+    const QGraphicsItem *t1 = item1;
+    while (item1Depth > item2Depth && (p = p->d_ptr->parent)) {
+        if (p == item2) {
+            // item2 is one of item1's ancestors; item1 is on top
+            return !(t1->d_ptr->flags & QGraphicsItem::ItemStacksBehindParent);
+        }
+        t1 = p;
+        --item1Depth;
+    }
+    p = item2;
+    const QGraphicsItem *t2 = item2;
+    while (item2Depth > item1Depth && (p = p->d_ptr->parent)) {
+        if (p == item1) {
+            // item1 is one of item2's ancestors; item1 is not on top
+            return (t2->d_ptr->flags & QGraphicsItem::ItemStacksBehindParent);
+        }
+        t2 = p;
+        --item2Depth;
+    }
+
+    // item1Ancestor is now at the same level as item2Ancestor, but not the same.
+    const QGraphicsItem *p1 = t1;
+    const QGraphicsItem *p2 = t2;
+    while (t1 && t1 != t2) {
+        p1 = t1;
+        p2 = t2;
+        t1 = t1->d_ptr->parent;
+        t2 = t2->d_ptr->parent;
+    }
+
+    // in case we have a common ancestor, we compare the immediate children in the ancestor's path.
+    // otherwise we compare the respective items' topLevelItems directly.
+    return qt_closestLeaf(p1, p2);
+}
+
+/*!
+    Returns true if \a item2 is on top of \a item1.
+    The items dont need to be siblings.
+
+    \internal
+*/
+inline bool qt_closestItemLast(const QGraphicsItem *item1, const QGraphicsItem *item2)
+{
+    return qt_closestItemFirst(item2, item1);
+}
 
 /*!
     \internal
@@ -642,7 +726,7 @@ inline bool qt_closestLeaf(const QGraphicsItem *item1, const QGraphicsItem *item
 /*!
     \internal
 */
-static inline bool qt_notclosestLeaf(const QGraphicsItem *item1, const QGraphicsItem *item2)
+inline bool qt_notclosestLeaf(const QGraphicsItem *item1, const QGraphicsItem *item2)
 { return qt_closestLeaf(item2, item1); }
 
 /*
diff --git a/src/gui/graphicsview/qgraphicslayout_p.h b/src/gui/graphicsview/qgraphicslayout_p.h
index 59c6dba..4aeae39 100644
--- a/src/gui/graphicsview/qgraphicslayout_p.h
+++ b/src/gui/graphicsview/qgraphicslayout_p.h
@@ -60,6 +60,8 @@
 #include "qgraphicslayout.h"
 #include "qgraphicslayoutitem_p.h"
 #include <QtGui/qstyle.h>
+#include <QtGui/qwidget.h>
+#include <QtGui/qstyleoption.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -76,6 +78,55 @@ inline bool qt_graphicsLayoutDebug()
 }
 #endif
 
+
+class QLayoutStyleInfo
+{
+public:
+    inline QLayoutStyleInfo() { invalidate(); }
+    inline QLayoutStyleInfo(QStyle *style, QWidget *widget)
+        : m_valid(true), m_style(style), m_widget(widget) 
+    {
+        Q_ASSERT(style);
+        if (widget) //###
+            m_styleOption.initFrom(widget);
+        m_defaultSpacing[0] = style->pixelMetric(QStyle::PM_LayoutHorizontalSpacing);
+        m_defaultSpacing[1] = style->pixelMetric(QStyle::PM_LayoutVerticalSpacing);
+    }
+
+    inline void invalidate() { m_valid = false; m_style = 0; m_widget = 0; }
+
+    inline QStyle *style() const { return m_style; }
+    inline QWidget *widget() const { return m_widget; }
+
+    inline bool operator==(const QLayoutStyleInfo &other)
+        { return m_style == other.m_style && m_widget == other.m_widget; }
+    inline bool operator!=(const QLayoutStyleInfo &other)
+        { return !(*this == other); }
+
+    inline void setDefaultSpacing(Qt::Orientation o, qreal spacing){
+        if (spacing >= 0)
+            m_defaultSpacing[o - 1] = spacing;
+    }
+
+    inline qreal defaultSpacing(Qt::Orientation o) const {
+        return m_defaultSpacing[o - 1];
+    }
+
+    inline qreal perItemSpacing(QSizePolicy::ControlType control1, 
+                                  QSizePolicy::ControlType control2,
+                                  Qt::Orientation orientation) const
+    {
+        Q_ASSERT(style());
+        return style()->layoutSpacing(control1, control2, orientation, &m_styleOption, widget());
+    }
+private:
+    bool m_valid;
+    QStyle *m_style;
+    QWidget *m_widget;
+    QStyleOption m_styleOption;
+    qreal m_defaultSpacing[2];
+};
+
 class Q_AUTOTEST_EXPORT QGraphicsLayoutPrivate : public QGraphicsLayoutItemPrivate
 {
     Q_DECLARE_PUBLIC(QGraphicsLayout)
diff --git a/src/gui/graphicsview/qgraphicslinearlayout.cpp b/src/gui/graphicsview/qgraphicslinearlayout.cpp
index 0aa68df..cb68741 100644
--- a/src/gui/graphicsview/qgraphicslinearlayout.cpp
+++ b/src/gui/graphicsview/qgraphicslinearlayout.cpp
@@ -59,7 +59,7 @@
 
     You can add widgets, layouts, stretches (addStretch(), insertStretch() or
     setStretchFactor()), and spacings (setItemSpacing()) to a linear
-    layout. The layout takes ownership of the items. In some cases when the layout 
+    layout. The layout takes ownership of the items. In some cases when the layout
     item also inherits from QGraphicsItem (such as QGraphicsWidget) there will be a
     ambiguity in ownership because the layout item belongs to two ownership hierarchies.
 	See the documentation of QGraphicsLayoutItem::setOwnedByLayout() how to handle
@@ -208,7 +208,7 @@ QGraphicsLinearLayout::~QGraphicsLinearLayout()
     for (int i = count() - 1; i >= 0; --i) {
         QGraphicsLayoutItem *item = itemAt(i);
         // The following lines can be removed, but this removes the item
-        // from the layout more efficiently than the implementation of 
+        // from the layout more efficiently than the implementation of
         // ~QGraphicsLayoutItem.
         removeAt(i);
         if (item) {
@@ -272,6 +272,10 @@ void QGraphicsLinearLayout::insertItem(int index, QGraphicsLayoutItem *item)
         qWarning("QGraphicsLinearLayout::insertItem: cannot insert null item");
         return;
     }
+    if (item == this) {
+        qWarning("QGraphicsLinearLayout::insertItem: cannot insert itself");
+        return;
+    }
     d->addChildLayoutItem(item);
 
     Q_ASSERT(item);
@@ -538,18 +542,21 @@ void QGraphicsLinearLayout::invalidate()
     QGraphicsLayout::invalidate();
 }
 
-#ifdef QT_DEBUG
+/*!
+    \internal
+*/
 void QGraphicsLinearLayout::dump(int indent) const
 {
+#ifdef QT_DEBUG
     if (qt_graphicsLayoutDebug()) {
         Q_D(const QGraphicsLinearLayout);
         qDebug("%*s%s layout", indent, "",
                d->orientation == Qt::Horizontal ? "Horizontal" : "Vertical");
         d->engine.dump(indent + 1);
     }
-}
 #endif
+}
 
 QT_END_NAMESPACE
-        
+
 #endif //QT_NO_GRAPHICSVIEW
diff --git a/src/gui/graphicsview/qgraphicslinearlayout.h b/src/gui/graphicsview/qgraphicslinearlayout.h
index 742392e..15fe81a 100644
--- a/src/gui/graphicsview/qgraphicslinearlayout.h
+++ b/src/gui/graphicsview/qgraphicslinearlayout.h
@@ -97,9 +97,7 @@ public:
     Q5SizePolicy::ControlTypes controlTypes(LayoutSide side) const;
 #endif
 
-#ifdef QT_DEBUG
     void dump(int indent = 0) const;
-#endif
 
 protected:
 #if 0
diff --git a/src/gui/graphicsview/qgraphicsproxywidget.cpp b/src/gui/graphicsview/qgraphicsproxywidget.cpp
index b7a3962..e9173a9 100644
--- a/src/gui/graphicsview/qgraphicsproxywidget.cpp
+++ b/src/gui/graphicsview/qgraphicsproxywidget.cpp
@@ -57,6 +57,9 @@
 #include <QtGui/qpainter.h>
 #include <QtGui/qstyleoption.h>
 #include <QtGui/qgraphicsview.h>
+#include <QtGui/qlistview.h>
+#include <QtGui/qlineedit.h>
+#include <QtGui/qtextedit.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -86,7 +89,9 @@ QT_BEGIN_NAMESPACE
     of embedded widgets through creating a child proxy for each popup. This
     means that when an embedded QComboBox shows its popup list, a new
     QGraphicsProxyWidget is created automatically, embedding the popup, and
-    positioning it correctly.
+    positioning it correctly. This only works if the popup is child of the
+    embedded widget (for example QToolButton::setMenu() requires the QMenu instance
+    to be child of the QToolButton).
 
     \section1 Embedding a Widget with QGraphicsProxyWidget
 
@@ -184,6 +189,7 @@ QT_BEGIN_NAMESPACE
 */
 
 extern bool qt_sendSpontaneousEvent(QObject *, QEvent *);
+extern bool qt_tab_all_widgets;
 
 /*!
     \internal
@@ -369,6 +375,7 @@ QVariant QGraphicsProxyWidgetPrivate::inputMethodQueryHelper(Qt::InputMethodQuer
 
 /*!
     \internal
+    Some of the logic is shared with QApplicationPrivate::focusNextPrevChild_helper
 */
 QWidget *QGraphicsProxyWidgetPrivate::findFocusChild(QWidget *child, bool next) const
 {
@@ -382,14 +389,16 @@ QWidget *QGraphicsProxyWidgetPrivate::findFocusChild(QWidget *child, bool next)
         child = next ? child->d_func()->focus_next : child->d_func()->focus_prev;
         if ((next && child == widget) || (!next && child == widget->d_func()->focus_prev)) {
              return 0;
-	}
+        }
     }
 
     QWidget *oldChild = child;
+    uint focus_flag = qt_tab_all_widgets ? Qt::TabFocus : Qt::StrongFocus;
     do {
         if (child->isEnabled()
 	    && child->isVisibleTo(widget)
-            && (child->focusPolicy() & Qt::TabFocus)) {
+            && ((child->focusPolicy() & focus_flag) == focus_flag)
+            && !(child->d_func()->extra && child->d_func()->extra->focus_proxy)) {
             return child;
         }
         child = next ? child->d_func()->focus_next : child->d_func()->focus_prev;
diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index 0773559..5b0643d 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -242,7 +242,6 @@
 #include <QtGui/qstyleoption.h>
 #include <QtGui/qtooltip.h>
 #include <QtGui/qtransform.h>
-#include <QtGui/qgesture.h>
 #include <QtGui/qinputcontext.h>
 #include <QtGui/qgraphicseffect.h>
 #include <private/qapplication_p.h>
@@ -251,6 +250,14 @@
 #include <private/qt_x11_p.h>
 #endif
 #include <private/qgraphicseffect_p.h>
+#include <private/qgesturemanager_p.h>
+
+// #define GESTURE_DEBUG
+#ifndef GESTURE_DEBUG
+# define DEBUG if (0) qDebug
+#else
+# define DEBUG qDebug
+#endif
 
 QT_BEGIN_NAMESPACE
 
@@ -287,6 +294,7 @@ QGraphicsScenePrivate::QGraphicsScenePrivate()
       needSortTopLevelItems(true),
       holesInTopLevelSiblingIndex(false),
       topLevelSequentialOrdering(true),
+      scenePosDescendantsUpdatePending(false),
       stickyFocus(false),
       hasFocus(false),
       focusItem(0),
@@ -481,6 +489,55 @@ void QGraphicsScenePrivate::_q_processDirtyItems()
 
 /*!
     \internal
+*/
+void QGraphicsScenePrivate::setScenePosItemEnabled(QGraphicsItem *item, bool enabled)
+{
+    QGraphicsItem *p = item->d_ptr->parent;
+    while (p) {
+        p->d_ptr->scenePosDescendants = enabled;
+        p = p->d_ptr->parent;
+    }
+    if (!enabled && !scenePosDescendantsUpdatePending) {
+        scenePosDescendantsUpdatePending = true;
+        QMetaObject::invokeMethod(q_func(), "_q_updateScenePosDescendants", Qt::QueuedConnection);
+    }
+}
+
+/*!
+    \internal
+*/
+void QGraphicsScenePrivate::registerScenePosItem(QGraphicsItem *item)
+{
+    scenePosItems.insert(item);
+    setScenePosItemEnabled(item, true);
+}
+
+/*!
+    \internal
+*/
+void QGraphicsScenePrivate::unregisterScenePosItem(QGraphicsItem *item)
+{
+    scenePosItems.remove(item);
+    setScenePosItemEnabled(item, false);
+}
+
+/*!
+    \internal
+*/
+void QGraphicsScenePrivate::_q_updateScenePosDescendants()
+{
+    foreach (QGraphicsItem *item, scenePosItems) {
+        QGraphicsItem *p = item->d_ptr->parent;
+        while (p) {
+            p->d_ptr->scenePosDescendants = 1;
+            p = p->d_ptr->parent;
+        }
+    }
+    scenePosDescendantsUpdatePending = false;
+}
+
+/*!
+    \internal
 
     Schedules an item for removal. This function leaves some stale indexes
     around in the BSP tree if called from the item's destructor; these will
@@ -516,8 +573,19 @@ void QGraphicsScenePrivate::removeItemHelper(QGraphicsItem *item)
         widget->d_func()->fixFocusChainBeforeReparenting(0, 0);
     }
 
+    if (item->flags() & QGraphicsItem::ItemSendsScenePositionChanges)
+        unregisterScenePosItem(item);
+
     item->d_func()->scene = 0;
 
+    //We need to remove all children first because they might use their parent
+    //attributes (e.g. sceneTransform).
+    if (!item->d_ptr->inDestructor) {
+        // Remove all children recursively
+        for (int i = 0; i < item->d_ptr->children.size(); ++i)
+            q->removeItem(item->d_ptr->children.at(i));
+    }
+
     // Unregister focus proxy.
     item->d_ptr->resetFocusProxy();
 
@@ -564,12 +632,6 @@ void QGraphicsScenePrivate::removeItemHelper(QGraphicsItem *item)
             ++iterator;
     }
 
-    if (!item->d_ptr->inDestructor) {
-        // Remove all children recursively
-        for (int i = 0; i < item->d_ptr->children.size(); ++i)
-            q->removeItem(item->d_ptr->children.at(i));
-    }
-
     if (item->isPanel() && item->isVisible() && item->panelModality() != QGraphicsItem::NonModal)
         leaveModal(item);
 
@@ -684,6 +746,7 @@ void QGraphicsScenePrivate::setFocusItemHelper(QGraphicsItem *item,
         focusItem = 0;
         sendEvent(lastFocusItem, &event);
 
+#ifndef QT_NO_IM
         if (lastFocusItem
             && (lastFocusItem->flags() & QGraphicsItem::ItemAcceptsInputMethod)) {
             // Reset any visible preedit text
@@ -699,6 +762,7 @@ void QGraphicsScenePrivate::setFocusItemHelper(QGraphicsItem *item,
                     views.at(i)->inputContext()->reset();
             }
         }
+#endif //QT_NO_IM
     }
 
     if (item) {
@@ -1052,6 +1116,13 @@ bool QGraphicsScenePrivate::filterEvent(QGraphicsItem *item, QEvent *event)
 */
 bool QGraphicsScenePrivate::sendEvent(QGraphicsItem *item, QEvent *event)
 {
+    if (QGraphicsObject *object = item->toGraphicsObject()) {
+        if (qt_gestureManager) {
+            if (qt_gestureManager->filterEvent(object, event))
+                return true;
+        }
+    }
+
     if (filterEvent(item, event))
         return false;
     if (filterDescendantEvent(item, event))
@@ -2275,8 +2346,9 @@ void QGraphicsScene::clear()
     // NB! We have to clear the index before deleting items; otherwise the
     // index might try to access dangling item pointers.
     d->index->clear();
-    const QList<QGraphicsItem *> items = d->topLevelItems;
-    qDeleteAll(items);
+    // NB! QGraphicsScenePrivate::unregisterTopLevelItem() removes items
+    while (!d->topLevelItems.isEmpty())
+        delete d->topLevelItems.first();
     Q_ASSERT(d->topLevelItems.isEmpty());
     d->lastItemCount = 0;
     d->allItemsIgnoreHoverEvents = true;
@@ -2522,6 +2594,9 @@ void QGraphicsScene::addItem(QGraphicsItem *item)
         }
     }
 
+    if (item->flags() & QGraphicsItem::ItemSendsScenePositionChanges)
+        d->registerScenePosItem(item);
+
     // Ensure that newly added items that have subfocus set, gain
     // focus automatically if there isn't a focus item already.
     if (!d->focusItem && item != d->lastFocusItem && item->focusItem() == item)
@@ -2808,18 +2883,20 @@ void QGraphicsScene::removeItem(QGraphicsItem *item)
 }
 
 /*!
-    Returns the scene's current focus item, or 0 if no item currently has
-    focus.
+    When the scene is active, this functions returns the scene's current focus
+    item, or 0 if no item currently has focus. When the scene is inactive, this
+    functions returns the item that will gain input focus when the scene becomes
+    active.
 
     The focus item receives keyboard input when the scene receives a
     key event.
 
-    \sa setFocusItem(), QGraphicsItem::hasFocus()
+    \sa setFocusItem(), QGraphicsItem::hasFocus(), isActive()
 */
 QGraphicsItem *QGraphicsScene::focusItem() const
 {
     Q_D(const QGraphicsScene);
-    return d->focusItem;
+    return isActive() ? d->focusItem : d->lastFocusItem;
 }
 
 /*!
@@ -3365,6 +3442,10 @@ bool QGraphicsScene::event(QEvent *event)
     case QEvent::TouchEnd:
         d->touchEventHandler(static_cast<QTouchEvent *>(event));
         break;
+    case QEvent::Gesture:
+    case QEvent::GestureOverride:
+        d->gestureEventHandler(static_cast<QGestureEvent *>(event));
+        break;
     default:
         return QObject::event(event);
     }
@@ -4127,7 +4208,7 @@ static void _q_paintIntoCache(QPixmap *pix, QGraphicsItem *item, const QRegion &
     QRect br = pixmapExposed.boundingRect();
 
     // Don't use subpixmap if we get a full update.
-    if (pixmapExposed.isEmpty() || (pixmapExposed.numRects() == 1 && br.contains(pix->rect()))) {
+    if (pixmapExposed.isEmpty() || (pixmapExposed.rectCount() == 1 && br.contains(pix->rect()))) {
         pix->fill(Qt::transparent);
         pixmapPainter.begin(pix);
     } else {
@@ -4470,6 +4551,10 @@ void QGraphicsScenePrivate::drawItemHelper(QGraphicsItem *item, QPainter *painte
 void QGraphicsScenePrivate::drawItems(QPainter *painter, const QTransform *const viewTransform,
                                       QRegion *exposedRegion, QWidget *widget)
 {
+    // Make sure we don't have unpolished items before we draw.
+    if (!unpolishedItems.isEmpty())
+        _q_polishItems();
+
     QRectF exposedSceneRect;
     if (exposedRegion && indexMethod != QGraphicsScene::NoIndex) {
         exposedSceneRect = exposedRegion->boundingRect().adjusted(-1, -1, 1, 1);
@@ -4555,6 +4640,7 @@ void QGraphicsScenePrivate::drawSubtreeRecursive(QGraphicsItem *item, QPainter *
     if (itemHasChildren && itemClipsChildrenToShape)
         ENSURE_TRANSFORM_PTR;
 
+#ifndef QT_NO_GRAPHICSEFFECT
     if (item->d_ptr->graphicsEffect && item->d_ptr->graphicsEffect->isEnabled()) {
         ENSURE_TRANSFORM_PTR;
         QGraphicsItemPaintInfo info(viewTransform, transformPtr, effectTransform, exposedRegion, widget, &styleOptionTmp,
@@ -4569,10 +4655,17 @@ void QGraphicsScenePrivate::drawSubtreeRecursive(QGraphicsItem *item, QPainter *
         else
             painter->setWorldTransform(*transformPtr);
         painter->setOpacity(opacity);
-        item->d_ptr->graphicsEffect->draw(painter, source);
+
+        if (sourced->lastEffectTransform != painter->worldTransform()) {
+            sourced->lastEffectTransform = painter->worldTransform();
+            sourced->invalidateCache();
+        }
+        item->d_ptr->graphicsEffect->draw(painter);
         painter->setWorldTransform(restoreTransform);
         sourced->info = 0;
-    } else {
+    } else
+#endif //QT_NO_GRAPHICSEFFECT
+    {
         draw(item, painter, viewTransform, transformPtr, exposedRegion, widget, opacity,
              effectTransform, wasDirtyParentSceneTransform, drawItem);
     }
@@ -4741,10 +4834,12 @@ void QGraphicsScenePrivate::markDirty(QGraphicsItem *item, const QRectF &rect, b
     QGraphicsItem *p = item->d_ptr->parent;
     while (p) {
         p->d_ptr->dirtyChildren = 1;
+#ifndef QT_NO_GRAPHICSEFFECT
         if (p->d_ptr->graphicsEffect && p->d_ptr->graphicsEffect->isEnabled()) {
             p->d_ptr->dirty = 1;
             p->d_ptr->fullUpdatePending = 1;
         }
+#endif //QT_NO_GRAPHICSEFFECT
         p = p->d_ptr->parent;
     }
 }
@@ -4886,7 +4981,7 @@ void QGraphicsScenePrivate::processDirtyItemsRecursive(QGraphicsItem *item, bool
                     continue;
                 }
 
-                if (item->d_ptr->paintedViewBoundingRectsNeedRepaint && !paintedViewBoundingRect.isEmpty()) {
+                if (item->d_ptr->paintedViewBoundingRectsNeedRepaint) {
                     paintedViewBoundingRect.translate(viewPrivate->dirtyScrollOffset);
                     if (!viewPrivate->updateRect(paintedViewBoundingRect))
                         paintedViewBoundingRect = QRect(-1, -1, -1, -1); // Outside viewport.
@@ -4986,6 +5081,10 @@ void QGraphicsScene::drawItems(QPainter *painter,
                                const QStyleOptionGraphicsItem options[], QWidget *widget)
 {
     Q_D(QGraphicsScene);
+    // Make sure we don't have unpolished items before we draw.
+    if (!d->unpolishedItems.isEmpty())
+        d->_q_polishItems();
+
     QTransform viewTransform = painter->worldTransform();
     Q_UNUSED(options);
 
@@ -5297,7 +5396,7 @@ void QGraphicsScene::setActivePanel(QGraphicsItem *item)
 /*!
     \since 4.4
 
-    Returns the current active window, or 0 if there is no window is currently
+    Returns the current active window, or 0 if no window is currently
     active.
 
     \sa QGraphicsScene::setActiveWindow()
@@ -5699,6 +5798,336 @@ void QGraphicsScenePrivate::leaveModal(QGraphicsItem *panel)
     dispatchHoverEvent(&hoverEvent);
 }
 
+void QGraphicsScenePrivate::getGestureTargets(const QSet<QGesture *> &gestures,
+                                              QWidget *viewport,
+                                              QMap<Qt::GestureType, QGesture *> *conflictedGestures,
+                                              QList<QList<QGraphicsObject *> > *conflictedItems,
+                                              QHash<QGesture *, QGraphicsObject *> *normalGestures)
+{
+    foreach (QGesture *gesture, gestures) {
+        Qt::GestureType gestureType = gesture->gestureType();
+        if (gesture->hasHotSpot()) {
+            QPoint screenPos = gesture->hotSpot().toPoint();
+            QList<QGraphicsItem *> items = itemsAtPosition(screenPos, QPointF(), viewport);
+            QList<QGraphicsObject *> result;
+            for (int j = 0; j < items.size(); ++j) {
+                QGraphicsObject *item = items.at(j)->toGraphicsObject();
+                if (!item)
+                    continue;
+                QGraphicsItemPrivate *d = item->QGraphicsItem::d_func();
+                if (d->gestureContext.contains(gestureType)) {
+                    result.append(item);
+                }
+            }
+            DEBUG() << "QGraphicsScenePrivate::getGestureTargets:"
+                    << gesture << result;
+            if (result.size() == 1) {
+                normalGestures->insert(gesture, result.first());
+            } else if (!result.isEmpty()) {
+                conflictedGestures->insert(gestureType, gesture);
+                conflictedItems->append(result);
+            }
+        }
+    }
+}
+
+void QGraphicsScenePrivate::gestureEventHandler(QGestureEvent *event)
+{
+    QWidget *viewport = event->widget();
+    if (!viewport)
+        return;
+    QList<QGesture *> allGestures = event->gestures();
+    DEBUG() << "QGraphicsScenePrivate::gestureEventHandler:"
+            << "Delivering gestures:" <<  allGestures;
+
+    typedef QHash<QGraphicsObject *, QList<QGesture *> > GesturesPerItem;
+    GesturesPerItem gesturesPerItem;
+
+    QSet<QGesture *> startedGestures;
+    foreach (QGesture *gesture, allGestures) {
+        QGraphicsObject *target = gestureTargets.value(gesture, 0);
+        if (!target) {
+            // when we are not in started mode but don't have a target
+            // then the only one interested in gesture is the view/scene
+            if (gesture->state() == Qt::GestureStarted)
+                startedGestures.insert(gesture);
+        } else {
+            gesturesPerItem[target].append(gesture);
+        }
+    }
+
+    QMap<Qt::GestureType, QGesture *> conflictedGestures;
+    QList<QList<QGraphicsObject *> > conflictedItems;
+    QHash<QGesture *, QGraphicsObject *> normalGestures;
+    getGestureTargets(startedGestures, viewport, &conflictedGestures, &conflictedItems,
+                      &normalGestures);
+    DEBUG() << "QGraphicsScenePrivate::gestureEventHandler:"
+            << "Conflicting gestures:" <<  conflictedGestures.values() << conflictedItems;
+    Q_ASSERT((conflictedGestures.isEmpty() && conflictedItems.isEmpty()) ||
+              (!conflictedGestures.isEmpty() && !conflictedItems.isEmpty()));
+
+    // gestures that were sent as override events, but no one accepted them
+    QHash<QGesture *, QGraphicsObject *> ignoredConflictedGestures;
+
+    // deliver conflicted gestures as override events first
+    while (!conflictedGestures.isEmpty() && !conflictedItems.isEmpty()) {
+        // get the topmost item to deliver the override event
+        Q_ASSERT(!conflictedItems.isEmpty());
+        Q_ASSERT(!conflictedItems.first().isEmpty());
+        QGraphicsObject *topmost = conflictedItems.first().first();
+        for (int i = 1; i < conflictedItems.size(); ++i) {
+            QGraphicsObject *item = conflictedItems.at(i).first();
+            if (qt_closestItemFirst(item, topmost)) {
+                topmost = item;
+            }
+        }
+        // get a list of gestures to send to the item
+        QList<Qt::GestureType> grabbedGestures =
+                topmost->QGraphicsItem::d_func()->gestureContext.keys();
+        QList<QGesture *> gestures;
+        for (int i = 0; i < grabbedGestures.size(); ++i) {
+            if (QGesture *g = conflictedGestures.value(grabbedGestures.at(i), 0)) {
+                gestures.append(g);
+                if (!ignoredConflictedGestures.contains(g))
+                    ignoredConflictedGestures.insert(g, topmost);
+            }
+        }
+
+        // send gesture override to the topmost item
+        QGestureEvent ev(gestures);
+        ev.t = QEvent::GestureOverride;
+        ev.setWidget(event->widget());
+        // mark event and individual gestures as ignored
+        ev.ignore();
+        foreach(QGesture *g, gestures)
+            ev.setAccepted(g, false);
+        DEBUG() << "QGraphicsScenePrivate::gestureEventHandler:"
+                << "delivering override to"
+                << topmost << gestures;
+        sendEvent(topmost, &ev);
+        // mark all accepted gestures to deliver them as normal gesture events
+        foreach (QGesture *g, gestures) {
+            if (ev.isAccepted() || ev.isAccepted(g)) {
+                conflictedGestures.remove(g->gestureType());
+                gestureTargets.remove(g);
+                // add the gesture to the list of normal delivered gestures
+                normalGestures.insert(g, topmost);
+                DEBUG() << "QGraphicsScenePrivate::gestureEventHandler:"
+                        << "override was accepted:"
+                        << g << topmost;
+                ignoredConflictedGestures.remove(g);
+            }
+        }
+        // remove the item that we've already delivered from the list
+        for (int i = 0; i < conflictedItems.size(); ) {
+            QList<QGraphicsObject *> &items = conflictedItems[i];
+            if (items.first() == topmost) {
+                items.removeFirst();
+                if (items.isEmpty()) {
+                    conflictedItems.removeAt(i);
+                    continue;
+                }
+            }
+            ++i;
+        }
+    }
+
+    // put back those started gestures that are not in the conflicted state
+    // and remember their targets
+    QHash<QGesture *, QGraphicsObject *>::const_iterator it = normalGestures.begin(),
+                                                          e = normalGestures.end();
+    for (; it != e; ++it) {
+        QGesture *g = it.key();
+        QGraphicsObject *receiver = it.value();
+        Q_ASSERT(!gestureTargets.contains(g));
+        gestureTargets.insert(g, receiver);
+        gesturesPerItem[receiver].append(g);
+    }
+    it = ignoredConflictedGestures.begin();
+    e = ignoredConflictedGestures.end();
+    for (; it != e; ++it) {
+        QGesture *g = it.key();
+        QGraphicsObject *receiver = it.value();
+        Q_ASSERT(!gestureTargets.contains(g));
+        gestureTargets.insert(g, receiver);
+        gesturesPerItem[receiver].append(g);
+    }
+
+    DEBUG() << "QGraphicsScenePrivate::gestureEventHandler:"
+            << "Started gestures:" << normalGestures.keys()
+            << "All gestures:" << gesturesPerItem.values();
+
+    // deliver all events
+    QList<QGesture *> alreadyIgnoredGestures;
+    QHash<QGraphicsObject *, QSet<QGesture *> > itemIgnoredGestures;
+    QList<QGraphicsObject *> targetItems = gesturesPerItem.keys();
+    qSort(targetItems.begin(), targetItems.end(), qt_closestItemFirst);
+    for (int i = 0; i < targetItems.size(); ++i) {
+        QGraphicsObject *item = targetItems.at(i);
+        QList<QGesture *> gestures = gesturesPerItem.value(item);
+        // remove gestures that were already delivered once and were ignored
+        DEBUG() << "QGraphicsScenePrivate::gestureEventHandler:"
+                << "already ignored gestures for item"
+                << item << ":" << itemIgnoredGestures.value(item);
+
+        if (itemIgnoredGestures.contains(item)) // don't deliver twice to the same item
+            continue;
+
+        QGraphicsItemPrivate *gid = item->QGraphicsItem::d_func();
+        foreach(QGesture *g, alreadyIgnoredGestures) {
+            QMap<Qt::GestureType, Qt::GestureFlags>::iterator contextit =
+                    gid->gestureContext.find(g->gestureType());
+            bool deliver = contextit != gid->gestureContext.end() &&
+                (g->state() == Qt::GestureStarted ||
+                 (contextit.value() & Qt::ReceivePartialGestures));
+            if (deliver)
+                gestures += g;
+        }
+        if (gestures.isEmpty())
+            continue;
+        DEBUG() << "QGraphicsScenePrivate::gestureEventHandler:"
+                << "delivering to"
+                << item << gestures;
+        QGestureEvent ev(gestures);
+        ev.setWidget(event->widget());
+        sendEvent(item, &ev);
+        QSet<QGesture *> ignoredGestures;
+        foreach (QGesture *g, gestures) {
+            if (!ev.isAccepted() && !ev.isAccepted(g)) {
+                ignoredGestures.insert(g);
+            } else {
+                if (g->state() == Qt::GestureStarted)
+                    gestureTargets[g] = item;
+            }
+        }
+        if (!ignoredGestures.isEmpty()) {
+            // get a list of items under the (current) hotspot of each ignored
+            // gesture and start delivery again from the beginning
+            DEBUG() << "QGraphicsScenePrivate::gestureEventHandler:"
+                    << "item has ignored the event, will propagate."
+                    << item << ignoredGestures;
+            itemIgnoredGestures[item] += ignoredGestures;
+            QMap<Qt::GestureType, QGesture *> conflictedGestures;
+            QList<QList<QGraphicsObject *> > itemsForConflictedGestures;
+            QHash<QGesture *, QGraphicsObject *> normalGestures;
+            getGestureTargets(ignoredGestures, viewport,
+                              &conflictedGestures, &itemsForConflictedGestures,
+                              &normalGestures);
+            QSet<QGraphicsObject *> itemsSet = targetItems.toSet();
+            for (int k = 0; k < itemsForConflictedGestures.size(); ++k)
+                itemsSet += itemsForConflictedGestures.at(k).toSet();
+            targetItems = itemsSet.toList();
+            qSort(targetItems.begin(), targetItems.end(), qt_closestItemFirst);
+            alreadyIgnoredGestures = conflictedGestures.values();
+            DEBUG() << "QGraphicsScenePrivate::gestureEventHandler:"
+                    << "new targets:" << targetItems;
+            i = -1; // start delivery again
+            continue;
+        }
+    }
+    foreach (QGesture *g, startedGestures) {
+        if (g->gestureCancelPolicy() == QGesture::CancelAllInContext) {
+            DEBUG() << "lets try to cancel some";
+            // find gestures in context in Qt::GestureStarted or Qt::GestureUpdated state and cancel them
+            cancelGesturesForChildren(g, event->widget());
+        }
+    }
+
+    // forget about targets for gestures that have ended
+    foreach (QGesture *g, allGestures) {
+        switch (g->state()) {
+        case Qt::GestureFinished:
+        case Qt::GestureCanceled:
+            gestureTargets.remove(g);
+            break;
+        default:
+            break;
+        }
+    }
+}
+
+void QGraphicsScenePrivate::cancelGesturesForChildren(QGesture *original, QWidget *viewport)
+{
+    Q_ASSERT(original);
+    QGraphicsItem *originalItem = gestureTargets.value(original);
+    Q_ASSERT(originalItem);
+
+    // iterate over all active gestures and for each find the owner
+    // if the owner is part of our sub-hierarchy, cancel it.
+
+    QSet<QGesture *> canceledGestures;
+    QHash<QGesture *, QGraphicsObject *>::Iterator iter = gestureTargets.begin();
+    while (iter != gestureTargets.end()) {
+        QGraphicsObject *item = iter.value();
+        // note that we don't touch the gestures for our originalItem
+        if (item != originalItem && originalItem->isAncestorOf(item)) {
+            DEBUG() << "  found a gesture to cancel" << iter.key();
+            iter.key()->d_func()->state = Qt::GestureCanceled;
+            canceledGestures << iter.key();
+        }
+        ++iter;
+    }
+
+    // sort them per target item by cherry picking from almostCanceledGestures and delivering
+    QSet<QGesture *> almostCanceledGestures = canceledGestures;
+    QSet<QGesture *>::Iterator setIter;
+    while (!almostCanceledGestures.isEmpty()) {
+        QGraphicsObject *target = 0;
+        QSet<QGesture*> gestures;
+        setIter = almostCanceledGestures.begin();
+        // sort per target item
+        while (setIter != almostCanceledGestures.end()) {
+            QGraphicsObject *item = gestureTargets.value(*setIter);
+            if (target == 0)
+                target = item;
+            if (target == item) {
+                gestures << *setIter;
+                setIter = almostCanceledGestures.erase(setIter);
+            } else {
+                ++setIter;
+            }
+        }
+        Q_ASSERT(target);
+
+        QList<QGesture *> list = gestures.toList();
+        QGestureEvent ev(list);
+        sendEvent(target, &ev);
+
+        foreach (QGesture *g, list) {
+            if (ev.isAccepted() || ev.isAccepted(g))
+                gestures.remove(g);
+        }
+
+        foreach (QGesture *g, gestures) {
+            if (!g->hasHotSpot())
+                continue;
+
+            QPoint screenPos = g->hotSpot().toPoint();
+            QList<QGraphicsItem *> items = itemsAtPosition(screenPos, QPointF(), viewport);
+            for (int j = 0; j < items.size(); ++j) {
+                QGraphicsObject *item = items.at(j)->toGraphicsObject();
+                if (!item)
+                    continue;
+                QGraphicsItemPrivate *d = item->QGraphicsItem::d_func();
+                if (d->gestureContext.contains(g->gestureType())) {
+                    QList<QGesture *> list;
+                    list << g;
+                    QGestureEvent ev(list);
+                    sendEvent(item, &ev);
+                    if (ev.isAccepted() || ev.isAccepted(g))
+                        break; // successfully delivered
+                }
+            }
+        }
+    }
+
+    Q_ASSERT(qt_gestureManager); // it would be very odd if we got called without a manager.
+    for (setIter = canceledGestures.begin(); setIter != canceledGestures.end(); ++setIter) {
+        qt_gestureManager->recycle(*setIter);
+        gestureTargets.remove(*setIter);
+    }
+}
+
 QT_END_NAMESPACE
 
 #include "moc_qgraphicsscene.cpp"
diff --git a/src/gui/graphicsview/qgraphicsscene.h b/src/gui/graphicsview/qgraphicsscene.h
index d6d48d7..a47574e 100644
--- a/src/gui/graphicsview/qgraphicsscene.h
+++ b/src/gui/graphicsview/qgraphicsscene.h
@@ -299,6 +299,7 @@ private:
     Q_PRIVATE_SLOT(d_func(), void _q_emitUpdated())
     Q_PRIVATE_SLOT(d_func(), void _q_polishItems())
     Q_PRIVATE_SLOT(d_func(), void _q_processDirtyItems())
+    Q_PRIVATE_SLOT(d_func(), void _q_updateScenePosDescendants())
     friend class QGraphicsItem;
     friend class QGraphicsItemPrivate;
     friend class QGraphicsView;
diff --git a/src/gui/graphicsview/qgraphicsscene_p.h b/src/gui/graphicsview/qgraphicsscene_p.h
index 8073695..fdec466 100644
--- a/src/gui/graphicsview/qgraphicsscene_p.h
+++ b/src/gui/graphicsview/qgraphicsscene_p.h
@@ -122,6 +122,13 @@ public:
 
     void _q_processDirtyItems();
 
+    QSet<QGraphicsItem *> scenePosItems;
+    bool scenePosDescendantsUpdatePending;
+    void setScenePosItemEnabled(QGraphicsItem *item, bool enabled);
+    void registerScenePosItem(QGraphicsItem *item);
+    void unregisterScenePosItem(QGraphicsItem *item);
+    void _q_updateScenePosDescendants();
+
     void removeItemHelper(QGraphicsItem *item);
 
     QBrush backgroundBrush;
@@ -234,6 +241,7 @@ public:
         item->d_ptr->fullUpdatePending = 0;
         item->d_ptr->ignoreVisible = 0;
         item->d_ptr->ignoreOpacity = 0;
+#ifndef QT_NO_GRAPHICSEFFECT
         QGraphicsEffect::ChangeFlags flags;
         if (item->d_ptr->notifyBoundingRectChanged) {
             flags |= QGraphicsEffect::SourceBoundingRectChanged;
@@ -243,12 +251,15 @@ public:
             flags |= QGraphicsEffect::SourceInvalidated;
             item->d_ptr->notifyInvalidated = 0;
         }
+#endif //QT_NO_GRAPHICSEFFECT
         if (recursive) {
             for (int i = 0; i < item->d_ptr->children.size(); ++i)
                 resetDirtyItem(item->d_ptr->children.at(i), recursive);
         }
+#ifndef QT_NO_GRAPHICSEFFECT
         if (flags && item->d_ptr->graphicsEffect)
             item->d_ptr->graphicsEffect->sourceChanged(flags);
+#endif //QT_NO_GRAPHICSEFFECT
     }
 
     inline void ensureSortedTopLevelItems()
@@ -282,6 +293,14 @@ public:
     bool allItemsIgnoreTouchEvents;
     void enableTouchEventsOnViews();
 
+    QHash<QGesture *, QGraphicsObject *> gestureTargets;
+    void gestureEventHandler(QGestureEvent *event);
+    void getGestureTargets(const QSet<QGesture *> &gestures, QWidget *viewport,
+                           QMap<Qt::GestureType, QGesture *> *conflictedGestures,
+                           QList<QList<QGraphicsObject *> > *conflictedItems,
+                           QHash<QGesture *, QGraphicsObject *> *normalGestures);
+    void cancelGesturesForChildren(QGesture *original, QWidget *viewport);
+
     void updateInputMethodSensitivityInViews();
 
     QList<QGraphicsItem *> modalPanels;
diff --git a/src/gui/graphicsview/qgraphicsscenebsptreeindex.cpp b/src/gui/graphicsview/qgraphicsscenebsptreeindex.cpp
index e21183a..47ae3f1 100644
--- a/src/gui/graphicsview/qgraphicsscenebsptreeindex.cpp
+++ b/src/gui/graphicsview/qgraphicsscenebsptreeindex.cpp
@@ -405,70 +405,6 @@ QList<QGraphicsItem *> QGraphicsSceneBspTreeIndexPrivate::estimateItems(const QR
 }
 
 /*!
-    Returns true if \a item1 is on top of \a item2.
-
-    \internal
-*/
-bool QGraphicsSceneBspTreeIndexPrivate::closestItemFirst_withoutCache(const QGraphicsItem *item1, const QGraphicsItem *item2)
-{
-    // Siblings? Just check their z-values.
-    const QGraphicsItemPrivate *d1 = item1->d_ptr.data();
-    const QGraphicsItemPrivate *d2 = item2->d_ptr.data();
-    if (d1->parent == d2->parent)
-        return qt_closestLeaf(item1, item2);
-
-    // Find common ancestor, and each item's ancestor closest to the common
-    // ancestor.
-    int item1Depth = d1->depth();
-    int item2Depth = d2->depth();
-    const QGraphicsItem *p = item1;
-    const QGraphicsItem *t1 = item1;
-    while (item1Depth > item2Depth && (p = p->d_ptr->parent)) {
-        if (p == item2) {
-            // item2 is one of item1's ancestors; item1 is on top
-            return !(t1->d_ptr->flags & QGraphicsItem::ItemStacksBehindParent);
-        }
-        t1 = p;
-        --item1Depth;
-    }
-    p = item2;
-    const QGraphicsItem *t2 = item2;
-    while (item2Depth > item1Depth && (p = p->d_ptr->parent)) {
-        if (p == item1) {
-            // item1 is one of item2's ancestors; item1 is not on top
-            return (t2->d_ptr->flags & QGraphicsItem::ItemStacksBehindParent);
-        }
-        t2 = p;
-        --item2Depth;
-    }
-
-    // item1Ancestor is now at the same level as item2Ancestor, but not the same.
-    const QGraphicsItem *a1 = t1;
-    const QGraphicsItem *a2 = t2;
-    while (a1) {
-        const QGraphicsItem *p1 = a1;
-        const QGraphicsItem *p2 = a2;
-        a1 = a1->parentItem();
-        a2 = a2->parentItem();
-        if (a1 && a1 == a2)
-            return qt_closestLeaf(p1, p2);
-    }
-
-    // No common ancestor? Then just compare the items' toplevels directly.
-    return qt_closestLeaf(t1->topLevelItem(), t2->topLevelItem());
-}
-
-/*!
-    Returns true if \a item2 is on top of \a item1.
-
-    \internal
-*/
-bool QGraphicsSceneBspTreeIndexPrivate::closestItemLast_withoutCache(const QGraphicsItem *item1, const QGraphicsItem *item2)
-{
-    return closestItemFirst_withoutCache(item2, item1);
-}
-
-/*!
     Sort a list of \a itemList in a specific \a order and use the cache if requested.
 
     \internal
@@ -495,9 +431,9 @@ void QGraphicsSceneBspTreeIndexPrivate::sortItems(QList<QGraphicsItem *> *itemLi
         }
     } else {
         if (order == Qt::DescendingOrder) {
-            qSort(itemList->begin(), itemList->end(), closestItemFirst_withoutCache);
+            qSort(itemList->begin(), itemList->end(), qt_closestItemFirst);
         } else if (order == Qt::AscendingOrder) {
-            qSort(itemList->begin(), itemList->end(), closestItemLast_withoutCache);
+            qSort(itemList->begin(), itemList->end(), qt_closestItemLast);
         }
     }
 }
diff --git a/src/gui/graphicsview/qgraphicsscenebsptreeindex_p.h b/src/gui/graphicsview/qgraphicsscenebsptreeindex_p.h
index 0a86bb7..c130190 100644
--- a/src/gui/graphicsview/qgraphicsscenebsptreeindex_p.h
+++ b/src/gui/graphicsview/qgraphicsscenebsptreeindex_p.h
@@ -145,8 +145,6 @@ public:
     QList<QGraphicsItem *> estimateItems(const QRectF &, Qt::SortOrder, bool b = false);
 
     static void climbTree(QGraphicsItem *item, int *stackingOrder);
-    static bool closestItemFirst_withoutCache(const QGraphicsItem *item1, const QGraphicsItem *item2);
-    static bool closestItemLast_withoutCache(const QGraphicsItem *item1, const QGraphicsItem *item2);
 
     static inline bool closestItemFirst_withCache(const QGraphicsItem *item1, const QGraphicsItem *item2)
     {
diff --git a/src/gui/graphicsview/qgraphicstransform.cpp b/src/gui/graphicsview/qgraphicstransform.cpp
index ec1a2f5..83bc9e1 100644
--- a/src/gui/graphicsview/qgraphicstransform.cpp
+++ b/src/gui/graphicsview/qgraphicstransform.cpp
@@ -69,6 +69,9 @@
     objects are applied to a QGraphicsItem, all of the transformations
     are computed in true 3D space, with the projection back to 2D
     only occurring after the last QGraphicsTransform is applied.
+    The exception to this is QGraphicsRotation, which projects back to
+    2D after each rotation to preserve the perspective effect around
+    the X and Y axes.
 
     If you want to create your own configurable transformation, you can create
     a subclass of QGraphicsTransform (or any or the existing subclasses), and
@@ -90,8 +93,8 @@
 #include <QDebug>
 #include <QtCore/qmath.h>
 
+#ifndef QT_NO_GRAPHICSVIEW
 QT_BEGIN_NAMESPACE
-
 void QGraphicsTransformPrivate::setItem(QGraphicsItem *i)
 {
     if (item == i)
@@ -547,7 +550,7 @@ void QGraphicsRotation::applyTo(QMatrix4x4 *matrix) const
         return;
 
     matrix->translate(d->origin);
-    matrix->rotate(d->angle, d->axis.x(), d->axis.y(), d->axis.z());
+    matrix->projectedRotate(d->angle, d->axis.x(), d->axis.y(), d->axis.z());
     matrix->translate(-d->origin);
 }
 
@@ -562,3 +565,4 @@ void QGraphicsRotation::applyTo(QMatrix4x4 *matrix) const
 #include "moc_qgraphicstransform.cpp"
 
 QT_END_NAMESPACE
+#endif //QT_NO_GRAPHICSVIEW
diff --git a/src/gui/graphicsview/qgraphicstransform.h b/src/gui/graphicsview/qgraphicstransform.h
index 58075aa..58e3077 100644
--- a/src/gui/graphicsview/qgraphicstransform.h
+++ b/src/gui/graphicsview/qgraphicstransform.h
@@ -47,6 +47,7 @@
 #include <QtGui/QTransform>
 #include <QtGui/QMatrix4x4>
 
+#ifndef QT_NO_GRAPHICSVIEW
 QT_BEGIN_HEADER
 
 QT_BEGIN_NAMESPACE
@@ -150,5 +151,6 @@ private:
 QT_END_NAMESPACE
 
 QT_END_HEADER
+#endif //QT_NO_GRAPHICSVIEW
 
 #endif // QFXTRANSFORM_H
diff --git a/src/gui/graphicsview/qgraphicstransform_p.h b/src/gui/graphicsview/qgraphicstransform_p.h
index 9e708b2..ddf99bb 100644
--- a/src/gui/graphicsview/qgraphicstransform_p.h
+++ b/src/gui/graphicsview/qgraphicstransform_p.h
@@ -54,7 +54,7 @@
 //
 
 #include "private/qobject_p.h"
-
+#ifndef QT_NO_GRAPHICSVIEW
 QT_BEGIN_NAMESPACE
 
 class QGraphicsItem;
@@ -73,5 +73,6 @@ public:
 };
 
 QT_END_NAMESPACE
+#endif //QT_NO_GRAPHCISVIEW
 
 #endif // QGRAPHICSTRANSFORM_P_H
diff --git a/src/gui/graphicsview/qgraphicsview.cpp b/src/gui/graphicsview/qgraphicsview.cpp
index 32747cc..3f9f443 100644
--- a/src/gui/graphicsview/qgraphicsview.cpp
+++ b/src/gui/graphicsview/qgraphicsview.cpp
@@ -281,6 +281,7 @@ static const int QGRAPHICSVIEW_PREALLOC_STYLE_OPTIONS = 503; // largest prime <
 #include <QtGui/qstyleoption.h>
 #include <QtGui/qinputcontext.h>
 #ifdef Q_WS_X11
+#include <QtGui/qpaintengine.h>
 #include <private/qt_x11_p.h>
 #endif
 
@@ -977,7 +978,7 @@ QList<QGraphicsItem *> QGraphicsViewPrivate::findItems(const QRegion &exposedReg
     // Step 2) If the expose region is a simple rect and the view is only
     // translated or scaled, search for items using
     // QGraphicsScene::items(QRectF).
-    bool simpleRectLookup =  exposedRegion.numRects() == 1 && matrix.type() <= QTransform::TxScale;
+    bool simpleRectLookup =  exposedRegion.rectCount() == 1 && matrix.type() <= QTransform::TxScale;
     if (simpleRectLookup) {
         return scene->items(exposedRegionSceneBounds,
                             Qt::IntersectsItemBoundingRect,
@@ -1511,6 +1512,13 @@ void QGraphicsView::setScene(QGraphicsScene *scene)
                    this, SLOT(updateSceneRect(QRectF)));
         d->scene->d_func()->removeView(this);
         d->connectedToScene = false;
+
+        if (isActiveWindow() && isVisible()) {
+            QEvent windowDeactivate(QEvent::WindowDeactivate);
+            QApplication::sendEvent(d->scene, &windowDeactivate);
+        }
+        if(hasFocus())
+            d->scene->clearFocus();
     }
 
     // Assign the new scene and update the contents (scrollbars, etc.)).
@@ -1532,6 +1540,11 @@ void QGraphicsView::setScene(QGraphicsScene *scene)
         // enable touch events if any items is interested in them
         if (!d->scene->d_func()->allItemsIgnoreTouchEvents)
             d->viewport->setAttribute(Qt::WA_AcceptTouchEvents);
+
+        if (isActiveWindow() && isVisible()) {
+            QEvent windowActivate(QEvent::WindowActivate);
+            QApplication::sendEvent(d->scene, &windowActivate);
+        }
     } else {
         d->recalculateContentSize();
     }
@@ -2637,6 +2650,19 @@ bool QGraphicsView::viewportEvent(QEvent *event)
             d->scene->d_func()->removePopup(d->scene->d_func()->popupWidgets.first());
         QApplication::sendEvent(d->scene, event);
         break;
+    case QEvent::Show:
+        if (d->scene && isActiveWindow()) {
+            QEvent windowActivate(QEvent::WindowActivate);
+            QApplication::sendEvent(d->scene, &windowActivate);
+        }
+        break;
+    case QEvent::Hide:
+        // spontaneous event will generate a WindowDeactivate.
+        if (!event->spontaneous() && d->scene && isActiveWindow()) {
+            QEvent windowDeactivate(QEvent::WindowDeactivate);
+            QApplication::sendEvent(d->scene, &windowDeactivate);
+        }
+        break;
     case QEvent::Leave:
         // ### This is a temporary fix for until we get proper mouse grab
         // events. activeMouseGrabberItem should be set to 0 if we lose the
@@ -2701,6 +2727,19 @@ bool QGraphicsView::viewportEvent(QEvent *event)
 
         return true;
     }
+    case QEvent::Gesture:
+    case QEvent::GestureOverride:
+    {
+        if (!isEnabled())
+            return false;
+
+        if (d->scene && d->sceneInteractionAllowed) {
+            QGestureEvent *gestureEvent = static_cast<QGestureEvent *>(event);
+            gestureEvent->setWidget(viewport());
+            (void) QApplication::sendEvent(d->scene, gestureEvent);
+        }
+        return true;
+    }
     default:
         break;
     }
@@ -3281,7 +3320,12 @@ void QGraphicsView::paintEvent(QPaintEvent *event)
             backgroundPainter.setClipRegion(d->backgroundPixmapExposed, Qt::ReplaceClip);
             if (viewTransformed)
                 backgroundPainter.setTransform(viewTransform);
-            backgroundPainter.setCompositionMode(QPainter::CompositionMode_Source);
+#ifdef Q_WS_X11
+#undef X11
+            if (backgroundPainter.paintEngine()->type() != QPaintEngine::X11)
+#define X11 qt_x11Data
+#endif
+                backgroundPainter.setCompositionMode(QPainter::CompositionMode_Source);
             drawBackground(&backgroundPainter, exposedSceneRect);
             d->backgroundPixmapExposed = QRegion();
         }
@@ -3306,6 +3350,14 @@ void QGraphicsView::paintEvent(QPaintEvent *event)
     if (!(d->optimizationFlags & IndirectPainting)) {
         d->scene->d_func()->drawItems(&painter, viewTransformed ? &viewTransform : 0,
                                       &d->exposedRegion, viewport());
+        // Make sure the painter's world transform is restored correctly when
+        // drawing without painter state protection (DontSavePainterState).
+        // We only change the worldTransform() so there's no need to do a full-blown
+        // save() and restore(). Also note that we don't have to do this in case of
+        // IndirectPainting (the else branch), because in that case we always save()
+        // and restore() in QGraphicsScene::drawItems().
+        if (!d->scene->d_func()->painterStateProtection)
+            painter.setWorldTransform(viewTransform);
     } else {
         // Find all exposed items
         bool allItems = false;
diff --git a/src/gui/graphicsview/qgraphicswidget.cpp b/src/gui/graphicsview/qgraphicswidget.cpp
index 35a3c13..d9c65bb 100644
--- a/src/gui/graphicsview/qgraphicswidget.cpp
+++ b/src/gui/graphicsview/qgraphicswidget.cpp
@@ -318,6 +318,12 @@ void QGraphicsWidget::resize(const QSizeF &size)
 */
 
 /*!
+    \property QGraphicsWidget::sizePolicy
+    \brief the size policy for the widget
+    \sa sizePolicy(), setSizePolicy(), QWidget::sizePolicy()
+*/
+
+/*!
     \property QGraphicsWidget::geometry
     \brief the geometry of the widget
 
@@ -410,6 +416,27 @@ void QGraphicsWidget::setGeometry(const QRectF &rect)
 */
 
 /*!
+    \property QGraphicsWidget::minimumSize
+    \brief the minimum size of the widget
+
+    \sa setMinimumSize(), minimumSize(), preferredSize, maximumSize
+*/
+
+/*!
+    \property QGraphicsWidget::preferredSize
+    \brief the preferred size of the widget
+
+    \sa setPreferredSize(), preferredSize(), minimumSize, maximumSize
+*/
+
+/*!
+    \property QGraphicsWidget::maximumSize
+    \brief the maximum size of the widget
+
+    \sa setMaximumSize(), maximumSize(), minimumSize, preferredSize
+*/
+
+/*!
     Sets the widget's contents margins to \a left, \a top, \a right and \a
     bottom.
 
@@ -1352,6 +1379,8 @@ void QGraphicsWidget::changeEvent(QEvent *event)
     case QEvent::StyleChange:
         // ### Don't unset if the margins are explicitly set.
         unsetWindowFrameMargins();
+        if (d->layout)
+            d->layout->invalidate();
     case QEvent::FontChange:
         update();
         updateGeometry();
diff --git a/src/gui/graphicsview/qgraphicswidget.h b/src/gui/graphicsview/qgraphicswidget.h
index 9c71140..05d3a49 100644
--- a/src/gui/graphicsview/qgraphicswidget.h
+++ b/src/gui/graphicsview/qgraphicswidget.h
@@ -74,6 +74,10 @@ class Q_GUI_EXPORT QGraphicsWidget : public QGraphicsObject, public QGraphicsLay
     Q_PROPERTY(QFont font READ font WRITE setFont)
     Q_PROPERTY(Qt::LayoutDirection layoutDirection READ layoutDirection WRITE setLayoutDirection RESET unsetLayoutDirection)
     Q_PROPERTY(QSizeF size READ size WRITE resize)
+    Q_PROPERTY(QSizeF minimumSize READ minimumSize WRITE setMinimumSize)
+    Q_PROPERTY(QSizeF preferredSize READ preferredSize WRITE setPreferredSize)
+    Q_PROPERTY(QSizeF maximumSize READ maximumSize WRITE setMaximumSize)
+    Q_PROPERTY(QSizePolicy sizePolicy READ sizePolicy WRITE setSizePolicy)
     Q_PROPERTY(Qt::FocusPolicy focusPolicy READ focusPolicy WRITE setFocusPolicy)
     Q_PROPERTY(Qt::WindowFlags windowFlags READ windowFlags WRITE setWindowFlags)
     Q_PROPERTY(QString windowTitle READ windowTitle WRITE setWindowTitle)
diff --git a/src/gui/graphicsview/qgridlayoutengine_p.h b/src/gui/graphicsview/qgridlayoutengine_p.h
index a42a537..ed335a8 100644
--- a/src/gui/graphicsview/qgridlayoutengine_p.h
+++ b/src/gui/graphicsview/qgridlayoutengine_p.h
@@ -59,7 +59,7 @@
 #include "qmap.h"
 #include "qpair.h"
 #include "qvector.h"
-
+#include "qgraphicslayout_p.h"
 #include <float.h>
 
 QT_BEGIN_NAMESPACE
@@ -128,29 +128,6 @@ public:
 
 };
 
-class QLayoutStyleInfo
-{
-public:
-    inline QLayoutStyleInfo() { invalidate(); }
-    inline QLayoutStyleInfo(QStyle *style, QWidget *widget)
-        : q_valid(true), q_style(style), q_widget(widget) {}
-
-    inline void invalidate() { q_valid = false; q_style = 0; q_widget = 0; }
-
-    inline QStyle *style() const { return q_style; }
-    inline QWidget *widget() const { return q_widget; }
-
-    inline bool operator==(const QLayoutStyleInfo &other)
-        { return q_style == other.q_style && q_widget == other.q_widget; }
-    inline bool operator!=(const QLayoutStyleInfo &other)
-        { return !(*this == other); }
-
-private:
-    bool q_valid;
-    QStyle *q_style;
-    QWidget *q_widget;
-};
-
 class QGridLayoutBox
 {
 public:
diff --git a/src/gui/graphicsview/qsimplex_p.cpp b/src/gui/graphicsview/qsimplex_p.cpp
index b8f8fb4..cd40f9e 100644
--- a/src/gui/graphicsview/qsimplex_p.cpp
+++ b/src/gui/graphicsview/qsimplex_p.cpp
@@ -108,10 +108,8 @@ void QSimplex::clearDataStructures()
     // Constraints
     for (int i = 0; i < constraints.size(); ++i) {
         delete constraints[i]->helper.first;
-        constraints[i]->helper.first = 0;
-        constraints[i]->helper.second = 0.0;
         delete constraints[i]->artificial;
-        constraints[i]->artificial = 0;
+        delete constraints[i];
     }
     constraints.clear();
 
@@ -137,7 +135,23 @@ bool QSimplex::setConstraints(const QList<QSimplexConstraint *> newConstraints)
 
     if (newConstraints.isEmpty())
         return true;    // we are ok with no constraints
-    constraints = newConstraints;
+
+    // Make deep copy of constraints. We need this copy because we may change
+    // them in the simplification method.
+    for (int i = 0; i < newConstraints.size(); ++i) {
+        QSimplexConstraint *c = new QSimplexConstraint;
+        c->constant = newConstraints[i]->constant;
+        c->ratio = newConstraints[i]->ratio;
+        c->variables = newConstraints[i]->variables;
+        constraints << c;
+    }
+
+    // Remove constraints of type Var == K and replace them for their value.
+    if (!simplifyConstraints(&constraints)) {
+        qWarning() << "QSimplex: No feasible solution!";
+        clearDataStructures();
+        return false;
+    }
 
     ///////////////////////////////////////
     // Prepare variables and constraints //
@@ -274,7 +288,7 @@ bool QSimplex::setConstraints(const QList<QSimplexConstraint *> newConstraints)
     // original problem.
     // Otherwise, we clean up our structures and report there is
     // no feasible solution.
-    if (valueAt(0, columns - 1) != 0.0) {
+    if ((valueAt(0, columns - 1) != 0.0) && (qAbs(valueAt(0, columns - 1)) > 0.00001)) {
         qWarning() << "QSimplex: No feasible solution!";
         clearDataStructures();
         return false;
@@ -508,11 +522,21 @@ qreal QSimplex::solver(solverFactor factor)
     // Remove old objective
     clearRow(0);
 
-    // Set new objective
+    // Set new objective in the first row of the simplex matrix
+    qreal resultOffset = 0;
     QHash<QSimplexVariable *, qreal>::const_iterator iter;
     for (iter = objective->variables.constBegin();
          iter != objective->variables.constEnd();
          ++iter) {
+
+        // Check if the variable was removed in the simplification process.
+        // If so, we save its offset to the objective function and skip adding
+        // it to the matrix.
+        if (iter.key()->index == -1) {
+            resultOffset += iter.value() * iter.key()->result;
+            continue;
+        }
+
         setValueAt(0, iter.key()->index, -1 * factor * iter.value());
     }
 
@@ -525,7 +549,9 @@ qreal QSimplex::solver(solverFactor factor)
     }
 #endif
 
-    return factor * valueAt(0, columns - 1);
+    // Return the value calculated by the simplex plus the value of the
+    // fixed variables.
+    return (factor * valueAt(0, columns - 1)) + resultOffset;
 }
 
 /*!
@@ -571,4 +597,77 @@ void QSimplex::collectResults()
     }
 }
 
+/*!
+  \internal
+
+  Looks for single-valued variables and remove them from the constraints list.
+*/
+bool QSimplex::simplifyConstraints(QList<QSimplexConstraint *> *constraints)
+{
+    QHash<QSimplexVariable *, qreal> results;   // List of single-valued variables
+    bool modified = true;                       // Any chance more optimization exists?
+
+    while (modified) {
+        modified = false;
+
+        // For all constraints
+        QList<QSimplexConstraint *>::iterator iter = constraints->begin();
+        while (iter != constraints->end()) {
+            QSimplexConstraint *c = *iter;
+            if ((c->ratio == QSimplexConstraint::Equal) && (c->variables.count() == 1)) {
+                // Check whether this is a constraint of type Var == K
+                // If so, save its value to "results".
+                QSimplexVariable *variable = c->variables.constBegin().key();
+                qreal result = c->constant / c->variables.value(variable);
+
+                results.insert(variable, result);
+                variable->result = result;
+                variable->index = -1;
+                modified = true;
+
+            }
+
+            // Replace known values among their variables
+            QHash<QSimplexVariable *, qreal>::const_iterator r;
+            for (r = results.constBegin(); r != results.constEnd(); ++r) {
+                if (c->variables.contains(r.key())) {
+                    c->constant -= r.value() * c->variables.take(r.key());
+                    modified = true;
+                }
+            }
+
+            // Keep it normalized
+            if (c->constant < 0)
+                c->invert();
+
+            if (c->variables.isEmpty()) {
+                // If constraint became empty due to substitution, delete it.
+                if (c->isSatisfied() == false)
+                    // We must ensure that the constraint soon to be deleted would not
+                    // make the problem unfeasible if left behind. If that's the case,
+                    // we return false so the simplex solver can properly report that.
+                    return false;
+
+                delete c;
+                iter = constraints->erase(iter);
+            } else {
+                ++iter;
+            }
+        }
+    }
+
+    return true;
+}
+
+void QSimplexConstraint::invert()
+{
+    constant = -constant;
+    ratio = Ratio(2 - ratio);
+
+    QHash<QSimplexVariable *, qreal>::iterator iter;
+    for (iter = variables.begin(); iter != variables.end(); ++iter) {
+        iter.value() = -iter.value();
+    }
+}
+
 QT_END_NAMESPACE
diff --git a/src/gui/graphicsview/qsimplex_p.h b/src/gui/graphicsview/qsimplex_p.h
index 51991a9..a5816d1 100644
--- a/src/gui/graphicsview/qsimplex_p.h
+++ b/src/gui/graphicsview/qsimplex_p.h
@@ -63,7 +63,7 @@ struct QSimplexVariable
     QSimplexVariable() : result(0), index(0) {}
 
     qreal result;
-    uint index;
+    int index;
 };
 
 
@@ -95,7 +95,8 @@ struct QSimplexConstraint
     QPair<QSimplexVariable *, qreal> helper;
     QSimplexVariable * artificial;
 
-#ifdef QT_DEBUG
+    void invert();
+
     bool isSatisfied() {
         qreal leftHandSide(0);
 
@@ -106,7 +107,7 @@ struct QSimplexConstraint
 
         Q_ASSERT(constant > 0 || qFuzzyCompare(1, 1 + constant));
 
-        if (qFuzzyCompare(1000 + leftHandSide, 1000 + constant))
+        if ((leftHandSide == constant) || qAbs(leftHandSide - constant) < 0.00000001)
             return true;
 
         switch (ratio) {
@@ -118,6 +119,30 @@ struct QSimplexConstraint
             return false;
         }
     }
+
+#ifdef QT_DEBUG
+    QString toString() {
+        QString result;
+        result += QString::fromAscii("-- QSimplexConstraint %1 --").arg(quintptr(this), 0, 16);
+
+        QHash<QSimplexVariable *, qreal>::const_iterator iter;
+        for (iter = variables.constBegin(); iter != variables.constEnd(); ++iter) {
+            result += QString::fromAscii("  %1 x %2").arg(iter.value()).arg(quintptr(iter.key()), 0, 16);
+        }
+
+        switch (ratio) {
+        case LessOrEqual:
+            result += QString::fromAscii("  (less) <= %1").arg(constant);
+            break;
+        case MoreOrEqual:
+            result += QString::fromAscii("  (more) >= %1").arg(constant);
+            break;
+        default:
+            result += QString::fromAscii("  (eqal) == %1").arg(constant);
+        }
+
+        return result;
+    }
 #endif
 };
 
@@ -129,7 +154,6 @@ public:
 
     qreal solveMin();
     qreal solveMax();
-    QList<QSimplexVariable *> constraintsVariables();
 
     bool setConstraints(const QList<QSimplexConstraint *> constraints);
     void setObjective(QSimplexConstraint *objective);
@@ -145,6 +169,7 @@ private:
     void combineRows(int toIndex, int fromIndex, qreal factor);
 
     // Simplex
+    bool simplifyConstraints(QList<QSimplexConstraint *> *constraints);
     int findPivotColumn();
     int pivotRowForColumn(int column);
     void reducedRowEchelon();
@@ -168,11 +193,6 @@ private:
     qreal *matrix;
 };
 
-inline QList<QSimplexVariable *> QSimplex::constraintsVariables()
-{
-    return variables;
-}
-
 inline qreal QSimplex::valueAt(int rowIndex, int columnIndex)
 {
     return matrix[rowIndex * columns + columnIndex];