Add a children private property needed for QML to support QGraphicsObject

Commit adds a private property that QML can use to add children for a given
item. This is a custom list that calls a callback which actually reparent
the item instead of just appending in the list (otherwise it will mess up
the state of QGraphicsView). This is needed because childItems() is pretty
useless you get a list but if you append something on it then it adds
that into a copy. Also the children property is the default property
a concept used by QML.

Width and Height private properties has been added in order to support
better the integration with QGraphicsWidget in QML. The actual implementation
is in the private class of QGI and QGraphicsWidget reimplements it to return
the geometry. (In 4.7 QDeclarativeItem reimplements it too).

This change should be harmless everything is private.

Task-number:QT-2757
Reviewed-by:andreas

6 files changed, 251 insertions, 0 deletions

diff --git a/src/gui/graphicsview/qgraphicsitem.cpp b/src/gui/graphicsview/qgraphicsitem.cpp
index e10c03a..f110a5c 100644
--- a/src/gui/graphicsview/qgraphicsitem.cpp
+++ b/src/gui/graphicsview/qgraphicsitem.cpp
@@ -5224,6 +5224,8 @@ void QGraphicsItemPrivate::addChild(QGraphicsItem *child)
     needSortChildren = 1; // ### maybe 0
     child->d_ptr->siblingIndex = children.size();
     children.append(child);
+    if (isObject)
+        emit static_cast<QGraphicsObject *>(q_ptr)->childrenChanged();
 }
 
 /*!
@@ -5246,6 +5248,8 @@ void QGraphicsItemPrivate::removeChild(QGraphicsItem *child)
     // the child is not guaranteed to be at the index after the list is sorted.
     // (see ensureSortedChildren()).
     child->d_ptr->siblingIndex = -1;
+    if (isObject)
+        emit static_cast<QGraphicsObject *>(q_ptr)->childrenChanged();
 }
 
 /*!
@@ -7453,6 +7457,88 @@ void QGraphicsObject::ungrabGesture(Qt::GestureType gesture)
     }
 }
 
+void QGraphicsItemPrivate::append(QDeclarativeListProperty<QGraphicsObject> *list, QGraphicsObject *item)
+{
+    QGraphicsItemPrivate::get(item)->setParentItemHelper(static_cast<QGraphicsObject *>(list->object), /*newParentVariant=*/0, /*thisPointerVariant=*/0);
+}
+
+/*!
+    Returns a list of this item's children.
+
+    The items are sorted by stacking order. This takes into account both the
+    items' insertion order and their Z-values.
+
+*/
+QDeclarativeListProperty<QGraphicsObject> QGraphicsItemPrivate::childrenList()
+{
+    Q_Q(QGraphicsItem);
+    if (isObject) {
+        QGraphicsObject *that = static_cast<QGraphicsObject *>(q);
+        return QDeclarativeListProperty<QGraphicsObject>(that, &children, QGraphicsItemPrivate::append);
+    } else {
+        //QGraphicsItem is not supported for this property
+        return QDeclarativeListProperty<QGraphicsObject>();
+    }
+}
+
+/*!
+  \internal
+  Returns the width of the item
+  Reimplemented by QGraphicsWidget
+*/
+qreal QGraphicsItemPrivate::width() const
+{
+    return 0;
+}
+
+/*!
+  \internal
+  Set the width of the item
+  Reimplemented by QGraphicsWidget
+*/
+void QGraphicsItemPrivate::setWidth(qreal w)
+{
+    Q_UNUSED(w);
+}
+
+/*!
+  \internal
+  Reset the width of the item
+  Reimplemented by QGraphicsWidget
+*/
+void QGraphicsItemPrivate::resetWidth()
+{
+}
+
+/*!
+  \internal
+  Returns the height of the item
+  Reimplemented by QGraphicsWidget
+*/
+qreal QGraphicsItemPrivate::height() const
+{
+    return 0;
+}
+
+/*!
+  \internal
+  Set the height of the item
+  Reimplemented by QGraphicsWidget
+*/
+void QGraphicsItemPrivate::setHeight(qreal h)
+{
+    Q_UNUSED(h);
+}
+
+/*!
+  \internal
+  Reset the height of the item
+  Reimplemented by QGraphicsWidget
+*/
+void QGraphicsItemPrivate::resetHeight()
+{
+}
+
 /*!
   \property QGraphicsObject::parent
   \brief the parent of the item
@@ -7639,6 +7725,23 @@ void QGraphicsObject::ungrabGesture(Qt::GestureType gesture)
   \sa scale, rotation, QGraphicsItem::transformOriginPoint()
 */
 
+/*!
+    \fn void QGraphicsObject::widthChanged()
+    \internal
+*/
+
+/*!
+    \fn void QGraphicsObject::heightChanged()
+    \internal
+*/
+
+/*!
+
+  \fn QGraphicsObject::childrenChanged()
+
+  This signal gets emitted whenever the children list changes
+  \internal
+*/
 
 /*!
     \class QAbstractGraphicsShapeItem
diff --git a/src/gui/graphicsview/qgraphicsitem.h b/src/gui/graphicsview/qgraphicsitem.h
index d72833b..5023f60 100644
--- a/src/gui/graphicsview/qgraphicsitem.h
+++ b/src/gui/graphicsview/qgraphicsitem.h
@@ -547,6 +547,10 @@ class Q_GUI_EXPORT QGraphicsObject : public QObject, public QGraphicsItem
     Q_PROPERTY(qreal rotation READ rotation WRITE setRotation NOTIFY rotationChanged)
     Q_PROPERTY(qreal scale READ scale WRITE setScale NOTIFY scaleChanged)
     Q_PROPERTY(QPointF transformOriginPoint READ transformOriginPoint WRITE setTransformOriginPoint)
+    Q_PRIVATE_PROPERTY(QGraphicsItem::d_func(), QDeclarativeListProperty<QGraphicsObject> children READ childrenList DESIGNABLE false NOTIFY childrenChanged)
+    Q_PRIVATE_PROPERTY(QGraphicsItem::d_func(), qreal width READ width WRITE setWidth NOTIFY widthChanged RESET resetWidth FINAL)
+    Q_PRIVATE_PROPERTY(QGraphicsItem::d_func(), qreal height READ height WRITE setHeight NOTIFY heightChanged RESET resetHeight FINAL)
+    Q_CLASSINFO("DefaultProperty", "children")
     Q_INTERFACES(QGraphicsItem)
 public:
     QGraphicsObject(QGraphicsItem *parent = 0);
@@ -571,6 +575,9 @@ Q_SIGNALS:
     void zChanged();
     void rotationChanged();
     void scaleChanged();
+    void childrenChanged();
+    void widthChanged();
+    void heightChanged();
 
 protected:
     QGraphicsObject(QGraphicsItemPrivate &dd, QGraphicsItem *parent, QGraphicsScene *scene);
diff --git a/src/gui/graphicsview/qgraphicsitem_p.h b/src/gui/graphicsview/qgraphicsitem_p.h
index ea04e0b..669ae1b 100644
--- a/src/gui/graphicsview/qgraphicsitem_p.h
+++ b/src/gui/graphicsview/qgraphicsitem_p.h
@@ -71,6 +71,62 @@ QT_BEGIN_NAMESPACE
 
 class QGraphicsItemPrivate;
 
+#ifndef QDECLARATIVELISTPROPERTY
+#define QDECLARATIVELISTPROPERTY
+template<typename T>
+struct QDeclarativeListProperty {
+    typedef void (*AppendFunction)(QDeclarativeListProperty<T> *, T*);
+    typedef int (*CountFunction)(QDeclarativeListProperty<T> *);
+    typedef T *(*AtFunction)(QDeclarativeListProperty<T> *, int);
+    typedef void (*ClearFunction)(QDeclarativeListProperty<T> *);
+
+    QDeclarativeListProperty()
+        : object(0), data(0), append(0), count(0), at(0), clear(0), dummy1(0), dummy2(0) {}
+    QDeclarativeListProperty(QObject *o, QList<T *> &list)
+        : object(o), data(&list), append(qlist_append), count(qlist_count), at(qlist_at),
+          clear(qlist_clear), dummy1(0), dummy2(0) {}
+    QDeclarativeListProperty(QObject *o, void *d, AppendFunction a, CountFunction c = 0, AtFunction t = 0,
+                    ClearFunction r = 0)
+        : object(o), data(d), append(a), count(c), at(t), clear(r), dummy1(0), dummy2(0) {}
+
+    bool operator==(const QDeclarativeListProperty &o) const {
+        return object == o.object &&
+               data == o.data &&
+               append == o.append &&
+               count == o.count &&
+               at == o.at &&
+               clear == o.clear;
+    }
+
+    QObject *object;
+    void *data;
+
+    AppendFunction append;
+
+    CountFunction count;
+    AtFunction at;
+
+    ClearFunction clear;
+
+    void *dummy1;
+    void *dummy2;
+
+private:
+    static void qlist_append(QDeclarativeListProperty *p, T *v) {
+        ((QList<T *> *)p->data)->append(v);
+    }
+    static int qlist_count(QDeclarativeListProperty *p) {
+        return ((QList<T *> *)p->data)->count();
+    }
+    static T *qlist_at(QDeclarativeListProperty *p, int idx) {
+        return ((QList<T *> *)p->data)->at(idx);
+    }
+    static void qlist_clear(QDeclarativeListProperty *p) {
+        return ((QList<T *> *)p->data)->clear();
+    }
+};
+#endif
+
 class QGraphicsItemCache
 {
 public:
@@ -237,6 +293,7 @@ public:
     void resolveDepth();
     void addChild(QGraphicsItem *child);
     void removeChild(QGraphicsItem *child);
+    QDeclarativeListProperty<QGraphicsObject> childrenList();
     void setParentItemHelper(QGraphicsItem *parent, const QVariant *newParentVariant,
                              const QVariant *thisPointerVariant);
     void childrenBoundingRectHelper(QTransform *x, QRectF *rect);
@@ -423,11 +480,21 @@ public:
 
     inline QTransform transformToParent() const;
     inline void ensureSortedChildren();
+    static void append(QDeclarativeListProperty<QGraphicsObject> *list, QGraphicsObject *item);
     static inline bool insertionOrder(QGraphicsItem *a, QGraphicsItem *b);
     void ensureSequentialSiblingIndex();
     inline void sendScenePosChange();
     virtual void siblingOrderChange();
 
+    // Private Properties
+    virtual qreal width() const;
+    virtual void setWidth(qreal);
+    virtual void resetWidth();
+
+    virtual qreal height() const;
+    virtual void setHeight(qreal);
+    virtual void resetHeight();
+
     QRectF childrenBoundingRect;
     QRectF needsRepaint;
     QMap<QWidget *, QRect> paintedViewBoundingRects;
diff --git a/src/gui/graphicsview/qgraphicswidget.cpp b/src/gui/graphicsview/qgraphicswidget.cpp
index f42fe4f..a091347 100644
--- a/src/gui/graphicsview/qgraphicswidget.cpp
+++ b/src/gui/graphicsview/qgraphicswidget.cpp
@@ -324,6 +324,14 @@ void QGraphicsWidget::resize(const QSizeF &size)
 */
 
 /*!
+
+  \fn QGraphicsWidget::geometryChanged()
+
+  This signal gets emitted whenever the geometry of the item changes
+  \internal
+*/
+
+/*!
     \property QGraphicsWidget::geometry
     \brief the geometry of the widget
 
@@ -391,6 +399,10 @@ void QGraphicsWidget::setGeometry(const QRectF &rect)
         QGraphicsSceneResizeEvent re;
         re.setOldSize(oldSize);
         re.setNewSize(newGeom.size());
+        if (oldSize.width() != newGeom.size().width())
+            emit widthChanged();
+        if (oldSize.height() != newGeom.size().height())
+            emit heightChanged();
         QApplication::sendEvent(this, &re);
     }
 }
@@ -2322,5 +2334,7 @@ void QGraphicsWidget::dumpFocusChain()
 #endif
 
 QT_END_NAMESPACE
+
+#include "moc_qgraphicswidget.cpp"
         
 #endif //QT_NO_GRAPHICSVIEW
diff --git a/src/gui/graphicsview/qgraphicswidget_p.cpp b/src/gui/graphicsview/qgraphicswidget_p.cpp
index 1835c74..6e397b6 100644
--- a/src/gui/graphicsview/qgraphicswidget_p.cpp
+++ b/src/gui/graphicsview/qgraphicswidget_p.cpp
@@ -44,6 +44,7 @@
 #ifndef QT_NO_GRAPHICSVIEW
 
 #include <QtCore/qdebug.h>
+#include <QtCore/qnumeric.h>
 #include "qgraphicswidget_p.h"
 #include "qgraphicslayout.h"
 #include "qgraphicsscene_p.h"
@@ -825,6 +826,56 @@ void QGraphicsWidgetPrivate::setLayout_helper(QGraphicsLayout *l)
     }
 }
 
+qreal QGraphicsWidgetPrivate::width() const
+{
+    Q_Q(const QGraphicsWidget);
+    return q->geometry().width();
+}
+
+void QGraphicsWidgetPrivate::setWidth(qreal w)
+{
+    if (qIsNaN(w))
+        return;
+    Q_Q(QGraphicsWidget);
+    if (q->geometry().width() == w)
+        return;
+
+    QRectF oldGeom = q->geometry();
+
+    q->setGeometry(QRectF(q->x(), q->y(), w, height()));
+}
+
+void QGraphicsWidgetPrivate::resetWidth()
+{
+    Q_Q(QGraphicsWidget);
+    q->setGeometry(QRectF(q->x(), q->y(), 0, height()));
+}
+
+qreal QGraphicsWidgetPrivate::height() const
+{
+    Q_Q(const QGraphicsWidget);
+    return q->geometry().height();
+}
+
+void QGraphicsWidgetPrivate::setHeight(qreal h)
+{
+    if (qIsNaN(h))
+        return;
+    Q_Q(QGraphicsWidget);
+    if (q->geometry().height() == h)
+        return;
+
+    QRectF oldGeom = q->geometry();
+
+    q->setGeometry(QRectF(q->x(), q->y(), width(), h));
+}
+
+void QGraphicsWidgetPrivate::resetHeight()
+{
+    Q_Q(QGraphicsWidget);
+    q->setGeometry(QRectF(q->x(), q->y(), width(), 0));
+}
+
 QT_END_NAMESPACE
 
 #endif //QT_NO_GRAPHICSVIEW
diff --git a/src/gui/graphicsview/qgraphicswidget_p.h b/src/gui/graphicsview/qgraphicswidget_p.h
index 2c5b3bf..f34a755 100644
--- a/src/gui/graphicsview/qgraphicswidget_p.h
+++ b/src/gui/graphicsview/qgraphicswidget_p.h
@@ -130,6 +130,15 @@ public:
     void windowFrameHoverLeaveEvent(QGraphicsSceneHoverEvent *event);
     bool hasDecoration() const;
 
+    // Private Properties
+    qreal width() const;
+    void setWidth(qreal);
+    void resetWidth();
+
+    qreal height() const;
+    void setHeight(qreal);
+    void resetHeight();
+
     // State
     inline int attributeToBitIndex(Qt::WidgetAttribute att) const
     {