diff -r 000000000000 -r 1918ee327afb src/gui/graphicsview/qgraphicsanchorlayout.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/gui/graphicsview/qgraphicsanchorlayout.cpp	Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,517 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+    \class QGraphicsAnchorLayout
+    \brief The QGraphicsAnchorLayout class provides a layout where one can anchor widgets
+    together in Graphics View.
+    \since 4.6
+    \ingroup appearance
+    \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().
+    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).
+*/
+
+/*!
+    \class QGraphicsAnchor
+    \brief The QGraphicsAnchor class represents an anchor between two items in a
+           QGraphicsAnchorLayout.
+    \since 4.6
+    \ingroup appearance
+    \ingroup geomanagement
+    \ingroup graphicsview-api
+
+    The graphics anchor provides an API that enables you to query and manipulate the
+    properties an anchor has. When an anchor is added to the layout with
+    QGraphicsAnchorLayout::addAnchor(), a QGraphicsAnchor instance is returned where the properties
+    are initialized to their default values. The properties can then be further changed, and they
+    will be picked up the next time the layout is activated.
+
+    \sa QGraphicsAnchorLayout::anchor()
+
+*/
+#include "qgraphicsanchorlayout_p.h"
+
+QT_BEGIN_NAMESPACE
+
+QGraphicsAnchor::QGraphicsAnchor(QGraphicsAnchorLayout *parentLayout)
+    : QObject(*(new QGraphicsAnchorPrivate))
+{
+    Q_D(QGraphicsAnchor);
+    Q_ASSERT(parentLayout);
+    d->layoutPrivate = parentLayout->d_func();
+}
+
+/*!
+    Removes the QGraphicsAnchor object from the layout and destroys it.
+*/
+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 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::addAnchor()
+*/
+void QGraphicsAnchor::setSpacing(qreal spacing)
+{
+    Q_D(QGraphicsAnchor);
+    d->setSpacing(spacing);
+}
+
+qreal QGraphicsAnchor::spacing() const
+{
+    Q_D(const QGraphicsAnchor);
+    return d->spacing();
+}
+
+void QGraphicsAnchor::unsetSpacing()
+{
+    Q_D(QGraphicsAnchor);
+    d->unsetSpacing();
+}
+
+/*!
+    Constructs a QGraphicsAnchorLayout instance.  \a parent is passed to
+    QGraphicsLayout's constructor.
+  */
+QGraphicsAnchorLayout::QGraphicsAnchorLayout(QGraphicsLayoutItem *parent)
+    : QGraphicsLayout(*new QGraphicsAnchorLayoutPrivate(), parent)
+{
+    Q_D(QGraphicsAnchorLayout);
+    d->createLayoutEdges();
+}
+
+/*!
+    Destroys the QGraphicsAnchorLayout object.
+*/
+QGraphicsAnchorLayout::~QGraphicsAnchorLayout()
+{
+    Q_D(QGraphicsAnchorLayout);
+
+    for (int i = count() - 1; i >= 0; --i) {
+        QGraphicsLayoutItem *item = d->items.at(i);
+        removeAt(i);
+        if (item) {
+            if (item->ownedByLayout())
+                delete item;
+        }
+    }
+
+    d->removeCenterConstraints(this, QGraphicsAnchorLayoutPrivate::Horizontal);
+    d->removeCenterConstraints(this, QGraphicsAnchorLayoutPrivate::Vertical);
+    d->deleteLayoutEdges();
+
+    Q_ASSERT(d->itemCenterConstraints[0].isEmpty());
+    Q_ASSERT(d->itemCenterConstraints[1].isEmpty());
+    Q_ASSERT(d->items.isEmpty());
+    Q_ASSERT(d->m_vertexList.isEmpty());
+}
+
+/*!
+    Creates an anchor between the edge \a firstEdge of item \a firstItem and the edge \a secondEdge
+    of item \a secondItem. The magnitude of the anchor is picked up from the style. Anchors
+    between a layout edge and an item edge will have a size of 0.
+    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.
+
+    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
+    horizontal spacing. The same behaviour applies to Bottom to Top anchors, (but they will use
+    the default vertical spacing). For all other anchor combinations, the spacing will be 0.
+    All anchoring functions will follow this rule.
+
+    The spacing can also be set manually by using QGraphicsAnchor::setSpacing() method.
+
+    Calling this function where \a firstItem or \a secondItem are ancestors of the layout have
+    undefined behaviour.
+
+    \sa addCornerAnchors(), addAnchors()
+ */
+QGraphicsAnchor *
+QGraphicsAnchorLayout::addAnchor(QGraphicsLayoutItem *firstItem, Qt::AnchorPoint firstEdge,
+                                 QGraphicsLayoutItem *secondItem, Qt::AnchorPoint secondEdge)
+{
+    Q_D(QGraphicsAnchorLayout);
+    QGraphicsAnchor *a = d->addAnchor(firstItem, firstEdge, secondItem, secondEdge);
+    invalidate();
+    return a;
+}
+
+/*!
+    Returns the anchor between the anchor points defined by \a firstItem and \a firstEdge and
+    \a secondItem and \a secondEdge. If there is no such anchor, the function will return 0.
+*/
+QGraphicsAnchor *
+QGraphicsAnchorLayout::anchor(QGraphicsLayoutItem *firstItem, Qt::AnchorPoint firstEdge,
+                              QGraphicsLayoutItem *secondItem, Qt::AnchorPoint secondEdge)
+{
+    Q_D(QGraphicsAnchorLayout);
+    return d->getAnchor(firstItem, firstEdge, secondItem, secondEdge);
+}
+
+/*!
+    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.
+
+    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
+
+    has the same effect as
+
+    \code
+      layout->addCornerAnchors(layout, Qt::TopLeft, b, Qt::TopLeft);
+    \endcode
+
+    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.
+*/
+void QGraphicsAnchorLayout::addCornerAnchors(QGraphicsLayoutItem *firstItem,
+                                             Qt::Corner firstCorner,
+                                             QGraphicsLayoutItem *secondItem,
+                                             Qt::Corner secondCorner)
+{
+    Q_D(QGraphicsAnchorLayout);
+
+    // Horizontal anchor
+    Qt::AnchorPoint firstEdge = (firstCorner & 1 ? Qt::AnchorRight: Qt::AnchorLeft);
+    Qt::AnchorPoint secondEdge = (secondCorner & 1 ? Qt::AnchorRight: Qt::AnchorLeft);
+    d->addAnchor(firstItem, firstEdge, secondItem, secondEdge);
+
+    // Vertical anchor
+    firstEdge = (firstCorner & 2 ? Qt::AnchorBottom: Qt::AnchorTop);
+    secondEdge = (secondCorner & 2 ? Qt::AnchorBottom: Qt::AnchorTop);
+    d->addAnchor(firstItem, firstEdge, secondItem, secondEdge);
+
+    invalidate();
+}
+
+/*!
+    Anchors two or four edges of \a firstItem with the corresponding
+    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
+
+    is the same as
+
+    \code
+    l->addAnchor(firstItem, Qt::AnchorLeft, secondItem, Qt::AnchorLeft);
+    l->addAnchor(firstItem, Qt::AnchorRight, secondItem, Qt::AnchorRight);
+    \endcode
+*/
+void QGraphicsAnchorLayout::addAnchors(QGraphicsLayoutItem *firstItem,
+                                       QGraphicsLayoutItem *secondItem,
+                                       Qt::Orientations orientations)
+{
+    if (orientations & Qt::Horizontal) {
+        addAnchor(secondItem, Qt::AnchorLeft, firstItem, Qt::AnchorLeft);
+        addAnchor(firstItem, Qt::AnchorRight, secondItem, Qt::AnchorRight);
+    }
+    if (orientations & Qt::Vertical) {
+        addAnchor(secondItem, Qt::AnchorTop, firstItem, Qt::AnchorTop);
+        addAnchor(firstItem, Qt::AnchorBottom, secondItem, Qt::AnchorBottom);
+    }
+}
+
+/*!
+    Sets the default horizontal spacing for the anchor layout to \a spacing.
+
+    \sa horizontalSpacing(), setVerticalSpacing(), setSpacing()
+*/
+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();
+}
+
+/*!
+    Sets the default vertical spacing for the anchor layout to \a spacing.
+
+    \sa verticalSpacing(), setHorizontalSpacing(), setSpacing()
+*/
+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();
+}
+
+/*!
+    Sets the default horizontal and the default vertical spacing for the anchor layout to \a 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();
+}
+
+/*!
+    Returns the default horizontal spacing for the anchor layout.
+
+    \sa verticalSpacing(), setHorizontalSpacing()
+*/
+qreal QGraphicsAnchorLayout::horizontalSpacing() const
+{
+    Q_D(const QGraphicsAnchorLayout);
+    return d->effectiveSpacing(QGraphicsAnchorLayoutPrivate::Horizontal);
+}
+
+/*!
+    Returns the default vertical spacing for the anchor layout.
+
+    \sa horizontalSpacing(), setVerticalSpacing()
+*/
+qreal QGraphicsAnchorLayout::verticalSpacing() const
+{
+    Q_D(const QGraphicsAnchorLayout);
+    return d->effectiveSpacing(QGraphicsAnchorLayoutPrivate::Vertical);
+}
+
+/*!
+    \reimp
+*/
+void QGraphicsAnchorLayout::setGeometry(const QRectF &geom)
+{
+    Q_D(QGraphicsAnchorLayout);
+
+    QGraphicsLayout::setGeometry(geom);
+    d->calculateVertexPositions(QGraphicsAnchorLayoutPrivate::Horizontal);
+    d->calculateVertexPositions(QGraphicsAnchorLayoutPrivate::Vertical);
+    d->setItemsGeometries(geom);
+}
+
+/*!
+    Removes the layout item at \a index without destroying it. Ownership of
+    the item is transferred to the caller.
+
+    Removing an item will also remove any of the anchors associated with it.
+
+    \sa itemAt(), count()
+*/
+void QGraphicsAnchorLayout::removeAt(int index)
+{
+    Q_D(QGraphicsAnchorLayout);
+    QGraphicsLayoutItem *item = d->items.value(index);
+
+    if (!item)
+        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);
+    d->items.remove(index);
+
+    item->setParentLayoutItem(0);
+    invalidate();
+}
+
+/*!
+    \reimp
+*/
+int QGraphicsAnchorLayout::count() const
+{
+    Q_D(const QGraphicsAnchorLayout);
+    return d->items.size();
+}
+
+/*!
+    \reimp
+*/
+QGraphicsLayoutItem *QGraphicsAnchorLayout::itemAt(int index) const
+{
+    Q_D(const QGraphicsAnchorLayout);
+    return d->items.value(index);
+}
+
+/*!
+    \reimp
+*/
+void QGraphicsAnchorLayout::invalidate()
+{
+    Q_D(QGraphicsAnchorLayout);
+    QGraphicsLayout::invalidate();
+    d->calculateGraphCacheDirty = 1;
+}
+
+/*!
+    \reimp
+*/
+QSizeF QGraphicsAnchorLayout::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
+{
+    Q_UNUSED(constraint);
+    Q_D(const QGraphicsAnchorLayout);
+
+    // Some setup calculations are delayed until the information is
+    // actually needed, avoiding unnecessary recalculations when
+    // adding multiple anchors.
+
+    // sizeHint() / effectiveSizeHint() already have a cache
+    // mechanism, using invalidate() to force recalculation. However
+    // sizeHint() is called three times after invalidation (for max,
+    // min and pref), but we just need do our setup once.
+
+    const_cast<QGraphicsAnchorLayoutPrivate *>(d)->calculateGraphs();
+
+    // ### apply constraint!
+    QSizeF engineSizeHint(
+        d->sizeHints[QGraphicsAnchorLayoutPrivate::Horizontal][which],
+        d->sizeHints[QGraphicsAnchorLayoutPrivate::Vertical][which]);
+
+    qreal left, top, right, bottom;
+    getContentsMargins(&left, &top, &right, &bottom);
+
+    return engineSizeHint + QSizeF(left + right, top + bottom);
+}
+
+QT_END_NAMESPACE