Merge branch 'master' of scm.dev.nokia.troll.no:qt/oslo-staging-2 into master-integration

* 'master' of scm.dev.nokia.troll.no:qt/oslo-staging-2:
  Enable the width-for-height codepath and add autotest for WFH.
  Use hasHeightForWidth() and hasWidthForHeight() instead of sizePolicy()
  Add hasWidthForHeight in order to support WFH in QGraphicsLayout.
  Compilation on S60 of external projects depending on private headers

7 files changed, 366 insertions, 92 deletions

diff --git a/src/declarative/util/qdeclarativeanimation.cpp b/src/declarative/util/qdeclarativeanimation.cpp
index 267642d..ed8343b 100644
--- a/src/declarative/util/qdeclarativeanimation.cpp
+++ b/src/declarative/util/qdeclarativeanimation.cpp
@@ -2939,4 +2939,8 @@ void QDeclarativeAnchorAnimation::transition(QDeclarativeStateActions &actions,
     }
 }
 
+QDeclarativeScriptActionPrivate::QDeclarativeScriptActionPrivate()
+    : QDeclarativeAbstractAnimationPrivate(), hasRunScriptScript(false), reversing(false), proxy(this), rsa(0) {}
+
+
 QT_END_NAMESPACE
diff --git a/src/declarative/util/qdeclarativeanimation_p_p.h b/src/declarative/util/qdeclarativeanimation_p_p.h
index e38580c..26c04d4 100644
--- a/src/declarative/util/qdeclarativeanimation_p_p.h
+++ b/src/declarative/util/qdeclarativeanimation_p_p.h
@@ -247,8 +247,7 @@ class QDeclarativeScriptActionPrivate : public QDeclarativeAbstractAnimationPriv
 {
     Q_DECLARE_PUBLIC(QDeclarativeScriptAction)
 public:
-    QDeclarativeScriptActionPrivate()
-        : QDeclarativeAbstractAnimationPrivate(), hasRunScriptScript(false), reversing(false), proxy(this), rsa(0) {}
+    QDeclarativeScriptActionPrivate();
 
     void init();
 
diff --git a/src/gui/graphicsview/qgraphicslayoutitem.cpp b/src/gui/graphicsview/qgraphicslayoutitem.cpp
index bfe734a..23f9923 100644
--- a/src/gui/graphicsview/qgraphicslayoutitem.cpp
+++ b/src/gui/graphicsview/qgraphicslayoutitem.cpp
@@ -285,10 +285,6 @@ bool QGraphicsLayoutItemPrivate::hasHeightForWidth() const
 
 bool QGraphicsLayoutItemPrivate::hasWidthForHeight() const
 {
-    // enable this code when we add QSizePolicy::hasWidthForHeight() (For 4.8)
-#if 1
-    return false;
-#else
     Q_Q(const QGraphicsLayoutItem);
     if (isLayout) {
         const QGraphicsLayout *l = static_cast<const QGraphicsLayout *>(q);
@@ -305,7 +301,6 @@ bool QGraphicsLayoutItemPrivate::hasWidthForHeight() const
         }
     }
     return q->sizePolicy().hasWidthForHeight();
-#endif
 }
 
 /*!
diff --git a/src/gui/graphicsview/qgraphicswidget_p.cpp b/src/gui/graphicsview/qgraphicswidget_p.cpp
index 3466733..f99749c 100644
--- a/src/gui/graphicsview/qgraphicswidget_p.cpp
+++ b/src/gui/graphicsview/qgraphicswidget_p.cpp
@@ -46,6 +46,7 @@
 #include <QtCore/qdebug.h>
 #include <QtCore/qnumeric.h>
 #include "qgraphicswidget_p.h"
+#include "qgraphicslayoutitem_p.h"
 #include "qgraphicslayout.h"
 #include "qgraphicsscene_p.h"
 #include <QtGui/qapplication.h>
@@ -415,8 +416,7 @@ static qreal minimumHeightForWidth(qreal width, qreal minh, qreal maxh,
                                    bool heightForWidth = true)
 {
     qreal minimumHeightForWidth = -1;
-    const QSizePolicy sp = widget->layout() ? widget->layout()->sizePolicy() : widget->sizePolicy();
-    const bool hasHFW = sp.hasHeightForWidth();
+    const bool hasHFW = QGraphicsLayoutItemPrivate::get(widget)->hasHeightForWidth();
     if (hasHFW == heightForWidth) {
         minimumHeightForWidth = hasHFW
                                 ? widget->effectiveSizeHint(Qt::MinimumSize, QSizeF(width, -1)).height()
@@ -505,21 +505,31 @@ static void _q_boundGeometryToSizeConstraints(const QRectF &startGeometry,
     qreal width = qBound(min.width(), proposedRect.width(), max.width());
     qreal height = qBound(min.height(), proposedRect.height(), max.height());
 
-    QSizePolicy sp = widget->sizePolicy();
-    if (const QGraphicsLayout *l = widget->layout()) {
-        sp = l->sizePolicy();
-    }
-    const bool hasHFW = sp.hasHeightForWidth(); // || sp.hasWidthForHeight();
+    const bool hasHFW = QGraphicsLayoutItemPrivate::get(widget)->hasHeightForWidth();
+    const bool hasWFH = QGraphicsLayoutItemPrivate::get(widget)->hasWidthForHeight();
 
-    const bool widthChanged = proposedRect.width() < widget->size().width();
-    const bool heightChanged = proposedRect.height() < widget->size().height();
+    const bool widthChanged = proposedRect.width() != widget->size().width();
+    const bool heightChanged = proposedRect.height() != widget->size().height();
 
-    if (hasHFW) {
+    if (hasHFW || hasWFH) {
         if (widthChanged || heightChanged) {
-            const qreal minh = min.height();
-            const qreal maxh = max.height();
-            const qreal proposedHFW = minimumHeightForWidth(width, minh, maxh, widget);
-            if (proposedHFW > proposedRect.height()) {
+            qreal minExtent;
+            qreal maxExtent;
+            qreal constraint;
+            qreal proposed;
+            if (hasHFW) {
+                minExtent = min.height();
+                maxExtent = max.height();
+                constraint = width;
+                proposed = proposedRect.height();
+            } else {
+                // width for height
+                minExtent = min.width();
+                maxExtent = max.width();
+                constraint = height;
+                proposed = proposedRect.width();
+            }
+            if (minimumHeightForWidth(constraint, minExtent, maxExtent, widget, hasHFW) > proposed) {
                 QSizeF effectiveSize = closestAcceptableSize(QSizeF(width, height), widget);
                 width = effectiveSize.width();
                 height = effectiveSize.height();
diff --git a/src/gui/kernel/qsizepolicy.h b/src/gui/kernel/qsizepolicy.h
index ff7b9ee..26cc1e1 100644
--- a/src/gui/kernel/qsizepolicy.h
+++ b/src/gui/kernel/qsizepolicy.h
@@ -62,12 +62,12 @@ private:
         HSize = 4,
         HMask = 0x0f,
         VMask = HMask << HSize,
-		CTShift = 9,
-		CTSize = 5,
-                WFHShift = CTShift + CTSize,
-		CTMask = ((0x1 << CTSize) - 1) << CTShift,
-		UnusedShift = CTShift + CTSize,
-		UnusedSize = 2
+        CTShift = 9,
+        CTSize = 5,
+        CTMask = ((0x1 << CTSize) - 1) << CTShift,
+        WFHShift = CTShift + CTSize,
+        UnusedShift = WFHShift + 1,
+        UnusedSize = 1
     };
 
 public:
@@ -134,6 +134,8 @@ public:
 
     void setHeightForWidth(bool b) { data = b ? (data | (1 << 2*HSize)) : (data & ~(1 << 2*HSize));  }
     bool hasHeightForWidth() const { return data & (1 << 2*HSize); }
+    void setWidthForHeight(bool b) { data = b ? (data | (1 << (WFHShift))) : (data & ~(1 << (WFHShift)));  }
+    bool hasWidthForHeight() const { return data & (1 << (WFHShift)); }
 
     bool operator==(const QSizePolicy& s) const { return data == s.data; }
     bool operator!=(const QSizePolicy& s) const { return data != s.data; }
@@ -200,15 +202,18 @@ private:
     QSizePolicy(int i) : data(i) { }
 
     quint32 data;
-/*  use bit flags instead, keep it here for improved readability for now
+/*  Qt5: Use bit flags instead, keep it here for improved readability for now.
+    We can maybe change it for Qt4, but we'd have to be careful, since the behaviour
+    is implementation defined. It usually varies between little- and big-endian compilers, but
+    it might also not vary.
     quint32 horzPolicy : 4;
     quint32 vertPolicy : 4;
     quint32 hfw : 1;
     quint32 ctype : 5;
     quint32 wfh : 1;
     quint32 padding : 1;   // we cannot use the highest bit
-    quint32 horStretch : 8;
     quint32 verStretch : 8;
+    quint32 horStretch : 8;
 */
 
 };
diff --git a/src/gui/kernel/qsizepolicy.qdoc b/src/gui/kernel/qsizepolicy.qdoc
index 7cd05c5..f6a350c 100644
--- a/src/gui/kernel/qsizepolicy.qdoc
+++ b/src/gui/kernel/qsizepolicy.qdoc
@@ -249,7 +249,7 @@
     Sets the flag determining whether the widget's preferred height
     depends on its width, to \a dependent.
 
-    \sa hasHeightForWidth()
+    \sa hasHeightForWidth(), setWidthForHeight()
 */
 
 /*!
@@ -262,6 +262,28 @@
 */
 
 /*!
+    \fn void QSizePolicy::setWidthForHeight(bool dependent)
+
+    Sets the flag determining whether the widget's width
+    depends on its height, to \a dependent.
+
+    This is only supported for QGraphicsLayout's subclasses.
+    It is not possible to have a layout with both height-for-width
+    and width-for-height constraints at the same time.
+
+    \sa hasWidthForHeight(), setHeightForWidth()
+*/
+
+/*!
+    \fn bool QSizePolicy::hasWidthForHeight() const
+
+    Returns true if the widget's width depends on its
+    height; otherwise returns false.
+
+    \sa setWidthForHeight()
+*/
+
+/*!
     \fn bool QSizePolicy::operator==(const QSizePolicy &other) const
 
     Returns true if this policy is equal to \a other; otherwise
diff --git a/tests/auto/qgraphicsgridlayout/tst_qgraphicsgridlayout.cpp b/tests/auto/qgraphicsgridlayout/tst_qgraphicsgridlayout.cpp
index 7346f07..82af71f 100644
--- a/tests/auto/qgraphicsgridlayout/tst_qgraphicsgridlayout.cpp
+++ b/tests/auto/qgraphicsgridlayout/tst_qgraphicsgridlayout.cpp
@@ -109,6 +109,7 @@ private slots:
     void styleInfoLeak();
     void task236367_maxSizeHint();
     void heightForWidth();
+    void widthForHeight();
 };
 
 class RectWidget : public QGraphicsWidget
@@ -225,9 +226,10 @@ struct ItemDesc
         return (*this);
     }
 
-    ItemDesc &heightForWidth(QSizeF (*fnConstraint)(Qt::SizeHint, const QSizeF &)) {
+    ItemDesc &dynamicConstraint(QSizeF (*fnConstraint)(Qt::SizeHint, const QSizeF &),
+                                Qt::Orientation orientation) {
         m_fnConstraint = fnConstraint;
-        m_constraintOrientation = Qt::Vertical;
+        m_constraintOrientation = orientation;
         return (*this);
     }
 
@@ -235,7 +237,7 @@ struct ItemDesc
         QSizePolicy sp = m_sizePolicy;
         if (m_fnConstraint) {
             sp.setHeightForWidth(m_constraintOrientation == Qt::Vertical);
-            //sp.setWidthForHeight(m_constraintOrientation == Qt::Horizontal);
+            sp.setWidthForHeight(m_constraintOrientation == Qt::Horizontal);
         }
 
         item->setSizePolicy(sp);
@@ -2174,10 +2176,50 @@ void tst_QGraphicsGridLayout::alignment2()
 static QSizeF hfw1(Qt::SizeHint, const QSizeF &constraint)
 {
     QSizeF result(constraint);
-    if (constraint.width() < 0 && constraint.height() < 0) {
+    const qreal ch = constraint.height();
+    const qreal cw = constraint.width();
+    if (cw < 0 && ch < 0) {
         return QSizeF(50, 400);
-    } else if (constraint.width() >= 0) {
-        result.setHeight(20000./constraint.width());
+    } else if (cw > 0) {
+        result.setHeight(20000./cw);
+    }
+    return result;
+}
+
+static QSizeF wfh1(Qt::SizeHint, const QSizeF &constraint)
+{
+    QSizeF result(constraint);
+    const qreal ch = constraint.height();
+    const qreal cw = constraint.width();
+    if (cw < 0 && ch < 0) {
+        return QSizeF(400, 50);
+    } else if (ch > 0) {
+        result.setWidth(20000./ch);
+    }
+    return result;
+}
+
+static QSizeF wfh2(Qt::SizeHint, const QSizeF &constraint)
+{
+    QSizeF result(constraint);
+    const qreal ch = constraint.height();
+    const qreal cw = constraint.width();
+    if (ch < 0 && cw < 0)
+        return QSizeF(50, 50);
+    if (ch >= 0)
+        result.setWidth(ch);
+    return result;
+}
+
+static QSizeF hfw3(Qt::SizeHint, const QSizeF &constraint)
+{
+    QSizeF result(constraint);
+    const qreal ch = constraint.height();
+    const qreal cw = constraint.width();
+    if (cw < 0 && ch < 0) {
+        return QSizeF(10, 10);
+    } else if (cw > 0) {
+        result.setHeight(100./cw);
     }
     return result;
 }
@@ -2212,7 +2254,7 @@ void tst_QGraphicsGridLayout::geometries_data()
                             );
 
     // change layout height and verify
-    QTest::newRow("hfw-h401") << (ItemList()
+    QTest::newRow("hfw-100x401") << (ItemList()
                                     << ItemDesc(0,0)
                                         .minSize(QSizeF(1,1))
                                         .preferredSize(QSizeF(50,10))
@@ -2229,7 +2271,7 @@ void tst_QGraphicsGridLayout::geometries_data()
                                         .minSize(QSizeF(40,40))
                                         .preferredSize(QSizeF(50,400))
                                         .maxSize(QSizeF(500, 500))
-                                        .heightForWidth(hfw1)
+                                        .dynamicConstraint(hfw1, Qt::Vertical)
                                 )
                             << QSizeF(100, 401)
                             << (RectList()
@@ -2238,7 +2280,7 @@ void tst_QGraphicsGridLayout::geometries_data()
                             );
 
 
-    QTest::newRow("hfw-h408") << (ItemList()
+    QTest::newRow("hfw-100x408") << (ItemList()
                                     << ItemDesc(0,0)
                                         .minSize(QSizeF(1,1))
                                         .preferredSize(QSizeF(50,10))
@@ -2255,7 +2297,7 @@ void tst_QGraphicsGridLayout::geometries_data()
                                         .minSize(QSizeF(40,40))
                                         .preferredSize(QSizeF(50,400))
                                         .maxSize(QSizeF(500, 500))
-                                        .heightForWidth(hfw1)
+                                        .dynamicConstraint(hfw1, Qt::Vertical)
                                 )
                             << QSizeF(100, 408)
                             << (RectList()
@@ -2280,7 +2322,7 @@ void tst_QGraphicsGridLayout::geometries_data()
                                         .minSize(QSizeF(40,40))
                                         .preferredSize(QSizeF(50,400))
                                         .maxSize(QSizeF(500, 500))
-                                        .heightForWidth(hfw1)
+                                        .dynamicConstraint(hfw1, Qt::Vertical)
                                 )
                             << QSizeF(100, 410)
                             << (RectList()
@@ -2288,7 +2330,7 @@ void tst_QGraphicsGridLayout::geometries_data()
                                 << QRectF(0, 10, 50,100) << QRectF(50, 10, 50,400)
                             );
 
-    QTest::newRow("hfw-h470") << (ItemList()
+    QTest::newRow("hfw-100x470") << (ItemList()
                                     << ItemDesc(0,0)
                                         .minSize(QSizeF(1,1))
                                         .preferredSize(QSizeF(50,10))
@@ -2305,7 +2347,7 @@ void tst_QGraphicsGridLayout::geometries_data()
                                         .minSize(QSizeF(40,40))
                                         .preferredSize(QSizeF(50,400))
                                         .maxSize(QSizeF(500, 500))
-                                        .heightForWidth(hfw1)
+                                        .dynamicConstraint(hfw1, Qt::Vertical)
                                 )
                             << QSizeF(100, 470)
                             << (RectList()
@@ -2315,7 +2357,7 @@ void tst_QGraphicsGridLayout::geometries_data()
 
 
     // change layout width and verify
-    QTest::newRow("hfw-w100") << (ItemList()
+    QTest::newRow("hfw-100x401") << (ItemList()
                                     << ItemDesc(0,0)
                                         .minSize(QSizeF(1,1))
                                         .preferredSize(QSizeF(50,10))
@@ -2332,7 +2374,7 @@ void tst_QGraphicsGridLayout::geometries_data()
                                         .minSize(QSizeF(40,40))
                                         .preferredSize(QSizeF(50,400))
                                         .maxSize(QSizeF(5000, 5000))
-                                        .heightForWidth(hfw1)
+                                        .dynamicConstraint(hfw1, Qt::Vertical)
                                 )
                             << QSizeF(100, 401)
                             << (RectList()
@@ -2340,7 +2382,7 @@ void tst_QGraphicsGridLayout::geometries_data()
                                 << QRectF( 0, 1,  50, 100) << QRectF( 50,  1,  50, 400)
                             );
 
-    QTest::newRow("hfw-w160") << (ItemList()
+    QTest::newRow("hfw-160x400") << (ItemList()
                                     << ItemDesc(0,0)
                                         .minSize(QSizeF(1,1))
                                         .preferredSize(QSizeF(50,10))
@@ -2357,16 +2399,16 @@ void tst_QGraphicsGridLayout::geometries_data()
                                         .minSize(QSizeF(40,40))
                                         .preferredSize(QSizeF(50,400))
                                         .maxSize(QSizeF(5000, 5000))
-                                        .heightForWidth(hfw1)
+                                        .dynamicConstraint(hfw1, Qt::Vertical)
                                 )
-                            << QSizeF(160, 401)
+                            << QSizeF(160, 400)
                             << (RectList()
                                 << QRectF( 0,   0,  80, 100) << QRectF( 80,   0,  80, 100)
                                 << QRectF( 0, 100,  80, 100) << QRectF( 80, 100,  80, 250)
                             );
 
 
-    QTest::newRow("hfw-w500") << (ItemList()
+    QTest::newRow("hfw-160x300") << (ItemList()
                                     << ItemDesc(0,0)
                                         .minSize(QSizeF(1,1))
                                         .preferredSize(QSizeF(50,10))
@@ -2383,12 +2425,145 @@ void tst_QGraphicsGridLayout::geometries_data()
                                         .minSize(QSizeF(40,40))
                                         .preferredSize(QSizeF(50,400))
                                         .maxSize(QSizeF(5000, 5000))
-                                        .heightForWidth(hfw1)
+                                        .dynamicConstraint(hfw1, Qt::Vertical)
+                                )
+                            << QSizeF(160, 300)
+                            << (RectList()
+                                << QRectF( 0,   0,  80,  50) << QRectF( 80,   0,  80,  50)
+                                << QRectF( 0,  50,  80, 100) << QRectF( 80,  50,  80, 250)
+                            );
+
+    QTest::newRow("hfw-20x40") << (ItemList()
+                                    << ItemDesc(0,0)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(0,1)
+                                        .minSize(QSizeF(1,10))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(1,0)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(1,1)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                        .dynamicConstraint(hfw3, Qt::Vertical)
+                                )
+                            << QSizeF(20, 40)
+                            << (RectList()
+                                << QRectF(0,  0, 10, 20) << QRectF(10,  0, 10, 20)
+                                << QRectF(0, 20, 10, 20) << QRectF(10, 20, 10, 10)
+                            );
+
+    QTest::newRow("wfh-300x160") << (ItemList()
+                                    << ItemDesc(0,0)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(10,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(0,1)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(10,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(1,0)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(10,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(1,1)
+                                        .minSize(QSizeF(10,10))
+                                        .preferredSize(QSizeF(400,50))
+                                        .maxSize(QSizeF(5000, 5000))
+                                        .dynamicConstraint(wfh1, Qt::Horizontal)
+                                )
+                            << QSizeF(300, 160)
+                            << (RectList()
+                                << QRectF( 0,   0,  50,  80) << QRectF( 50,   0, 100,  80)
+                                << QRectF( 0,  80,  50,  80) << QRectF( 50,  80, 250,  80)
+                            );
+
+    QTest::newRow("wfh-40x20") << (ItemList()
+                                    << ItemDesc(0,0)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(0,1)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(1,0)
+                                    // Note, must be 10 in order to match stretching  of wfh item
+                                    // below (the same stretch makes it easier to test)
+                                        .minSize(QSizeF(10,1))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(1,1)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                        .dynamicConstraint(wfh2, Qt::Horizontal)
                                 )
-                            << QSizeF(500, 401)
+                            << QSizeF(40, 20)
                             << (RectList()
-                                << QRectF( 0,   0, 100, 100) << QRectF(100,   0, 100, 100)
-                                << QRectF( 0, 100, 100, 100) << QRectF(100, 100, 400,  50)
+                                << QRectF(0,  0, 20, 10) << QRectF(20,  0, 20, 10)
+                                << QRectF(0, 10, 20, 10) << QRectF(20, 10, 10, 10)
+                            );
+
+    QTest::newRow("wfh-400x160") << (ItemList()
+                                    << ItemDesc(0,0)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(0,1)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(1,0)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(1,1)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                        .dynamicConstraint(wfh2, Qt::Horizontal)
+                                )
+
+                            << QSizeF(400, 160)
+                            << (RectList()
+                                << QRectF(0,  0, 100, 80) << QRectF(100,  0, 100, 80)
+                                << QRectF(0, 80, 100, 80) << QRectF(100, 80,  80, 80)
+                            );
+
+    QTest::newRow("wfh-160x100") << (ItemList()
+                                    << ItemDesc(0,0)
+                                        .minSize(QSizeF(1,1))
+                                        // Note, preferred width must be 50 in order to match
+                                        // preferred width of wfh item below.
+                                        // (The same preferred size makes the stretch the same, and
+                                        // makes it easier to test) (The stretch algorithm is a
+                                        // blackbox)
+                                        .preferredSize(QSizeF(50,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(0,1)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(10,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(1,0)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(10,50))
+                                        .maxSize(QSizeF(100, 100))
+                                    << ItemDesc(1,1)
+                                        .minSize(QSizeF(1,1))
+                                        .preferredSize(QSizeF(10,50))
+                                        .maxSize(QSizeF(500, 500))
+                                        .dynamicConstraint(wfh2, Qt::Horizontal)
+                                )
+                            << QSizeF(160, 100)
+                            << (RectList()
+                                << QRectF(0,  0,  80,  50) << QRectF( 80,  0,  80,  50)
+                                << QRectF(0, 50,  80,  50) << QRectF( 80, 50,  50,  50)
                             );
 
 }
@@ -2461,14 +2636,6 @@ void tst_QGraphicsGridLayout::task236367_maxSizeHint()
     QCOMPARE(widget->size(), QSizeF(w, h));
 }
 
-/*
-static qreal hfw(qreal w)
-{
-    if (w == 0)
-        return 20000;
-    return 20000/w;
-}
-*/
 static QSizeF hfw(Qt::SizeHint /*which*/, const QSizeF &constraint)
 {
     QSizeF result(constraint);
@@ -2485,7 +2652,16 @@ static QSizeF hfw(Qt::SizeHint /*which*/, const QSizeF &constraint)
     } else if (ch == 0) {
         result.setWidth(20000);
     }
+    return result;
+}
 
+static QSizeF wfh(Qt::SizeHint /*which*/, const QSizeF &constraint)
+{
+    QSizeF result(constraint);
+    const qreal ch = constraint.height();
+    if (ch >= 0) {
+        result.setWidth(ch);
+    }
     return result;
 }
 
@@ -2536,24 +2712,25 @@ void tst_QGraphicsGridLayout::heightForWidth()
     layout->setSpacing(0);
     RectWidget *w00 = new RectWidget;
     w00->setSizeHint(Qt::MinimumSize, QSizeF(1,1));
-    w00->setSizeHint(Qt::PreferredSize, QSizeF(10,10));
+    w00->setSizeHint(Qt::PreferredSize, QSizeF(50,50));
     w00->setSizeHint(Qt::MaximumSize, QSizeF(100,100));
     layout->addItem(w00, 0, 0);
 
     RectWidget *w01 = new RectWidget;
     w01->setSizeHint(Qt::MinimumSize, QSizeF(1,1));
-    w01->setSizeHint(Qt::PreferredSize, QSizeF(10,10));
+    w01->setSizeHint(Qt::PreferredSize, QSizeF(50,50));
     w01->setSizeHint(Qt::MaximumSize, QSizeF(100,100));
     layout->addItem(w01, 0, 1);
 
     RectWidget *w10 = new RectWidget;
     w10->setSizeHint(Qt::MinimumSize, QSizeF(1,1));
-    w10->setSizeHint(Qt::PreferredSize, QSizeF(10,10));
+    w10->setSizeHint(Qt::PreferredSize, QSizeF(50,50));
     w10->setSizeHint(Qt::MaximumSize, QSizeF(100,100));
     layout->addItem(w10, 1, 0);
 
     RectWidget *w11 = new RectWidget;
     w11->setSizeHint(Qt::MinimumSize, QSizeF(1,1));
+    w11->setSizeHint(Qt::PreferredSize, QSizeF(50,400));
     w11->setSizeHint(Qt::MaximumSize, QSizeF(30000,30000));
     w11->setConstraintFunction(hfw);
     QSizePolicy sp(QSizePolicy::Preferred, QSizePolicy::Preferred);
@@ -2562,42 +2739,104 @@ void tst_QGraphicsGridLayout::heightForWidth()
     layout->addItem(w11, 1, 1);
 
     QSizeF prefSize = layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(-1, -1));
-    QCOMPARE(prefSize, QSizeF(10+200, 10+100));
+    QCOMPARE(prefSize, QSizeF(50+50, 50+400));
 
     QCOMPARE(layout->effectiveSizeHint(Qt::MinimumSize, QSizeF(2, -1)), QSizeF(2, 20001));
-    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(2, -1)), QSizeF(2, 20010));
+    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(2, -1)), QSizeF(2, 20050));
     QCOMPARE(layout->effectiveSizeHint(Qt::MaximumSize, QSizeF(2, -1)), QSizeF(2, 20100));
-    qreal width1;
-    qreal width2;
-    expectedWidth(1, 10, 1, 200, 20, &width1, &width2);
-    QSizeF expectedSize = hfw(Qt::MinimumSize, QSizeF(width2, -1)) + QSizeF(width1, 1);
-    QCOMPARE(layout->effectiveSizeHint(Qt::MinimumSize, QSizeF(20, -1)), expectedSize);
-    expectedSize.rheight()+=9;
-    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(20, -1)), expectedSize);
-    expectedSize.rheight()+=90;
-    QCOMPARE(layout->effectiveSizeHint(Qt::MaximumSize, QSizeF(20, -1)), expectedSize);
-
-    expectedWidth(1, 10, 1, 200, 300, &width1, &width2);
-    expectedSize = hfw(Qt::MinimumSize, QSizeF(width2, -1)) + QSizeF(width1, 1);
-    QCOMPARE(layout->effectiveSizeHint(Qt::MinimumSize, QSizeF(300, -1)), expectedSize);
-    expectedSize.rheight()+=9;
-    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(300, -1)), expectedSize);
-    // the height of the hfw widget is shorter than the one to the left, which is 100, so
-    // the total height of the last row is 100 (which leaves the layout height to be 200)
-    QCOMPARE(layout->effectiveSizeHint(Qt::MaximumSize, QSizeF(300, -1)), QSizeF(300, 200));
-
-    // the hfw item is shorter than the item to the left
-    expectedWidth(1, 10, 1, 200, 500, &width1, &width2);
-    expectedSize = hfw(Qt::MinimumSize, QSizeF(width2, -1)) + QSizeF(width1, 1);
-    QCOMPARE(layout->effectiveSizeHint(Qt::MinimumSize, QSizeF(500, -1)), expectedSize);
-    expectedSize.rheight()+=9;
-    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(500, -1)), expectedSize);
+
+    QCOMPARE(layout->effectiveSizeHint(Qt::MinimumSize, QSizeF(20, -1)), QSizeF(20, 1 + 2000));
+    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(20, -1)), QSizeF(20, 50 + 2000));
+    QCOMPARE(layout->effectiveSizeHint(Qt::MaximumSize, QSizeF(20, -1)), QSizeF(20, 100 + 2000));
+
+    QCOMPARE(layout->effectiveSizeHint(Qt::MinimumSize, QSizeF(300, -1)), QSizeF(300, 1 + 100));
+    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(300, -1)), QSizeF(300, 50 + 100));
+    QCOMPARE(layout->effectiveSizeHint(Qt::MaximumSize, QSizeF(300, -1)), QSizeF(300, 100 + 100));
+
     // the height of the hfw widget is shorter than the one to the left, which is 100, so
     // the total height of the last row is 100 (which leaves the layout height to be 200)
-    QCOMPARE(layout->effectiveSizeHint(Qt::MaximumSize, QSizeF(500, -1)), QSizeF(500, 200));
+    QCOMPARE(layout->effectiveSizeHint(Qt::MaximumSize, QSizeF(500, -1)), QSizeF(500, 100 + 100));
+
+    // hfw item size: (500, 40) -> preferred size is maxed up to preferred size of item w10 (50)
+    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(600, -1)), QSizeF(600, 50 + 50));
 
 }
 
+void tst_QGraphicsGridLayout::widthForHeight()
+{
+    QGraphicsWidget *widget = new QGraphicsWidget;
+    QGraphicsGridLayout *layout = new QGraphicsGridLayout;
+    widget->setLayout(layout);
+    layout->setContentsMargins(0, 0, 0, 0);
+    layout->setSpacing(0);
+    RectWidget *w00 = new RectWidget;
+    w00->setMinimumSize(1, 1);
+    w00->setPreferredSize(50, 50);
+    w00->setMaximumSize(100, 100);
+
+    layout->addItem(w00, 0, 0);
+
+    RectWidget *w01 = new RectWidget;
+    w01->setMinimumSize(1,1);
+    w01->setPreferredSize(50,50);
+    w01->setMaximumSize(100,100);
+    layout->addItem(w01, 0, 1);
+
+    RectWidget *w10 = new RectWidget;
+    w10->setMinimumSize(1,1);
+    w10->setPreferredSize(50,50);
+    w10->setMaximumSize(100,100);
+    layout->addItem(w10, 1, 0);
+
+    RectWidget *w11 = new RectWidget;
+    w11->setMinimumSize(1,1);
+    w11->setPreferredSize(50, 50);
+    w11->setMaximumSize(30000,30000);
+    // This will make sure its always square.
+    w11->setConstraintFunction(wfh);
+    QSizePolicy sp(QSizePolicy::Preferred, QSizePolicy::Preferred);
+    sp.setWidthForHeight(true);
+    w11->setSizePolicy(sp);
+    layout->addItem(w11, 1, 1);
+
+    /*
+         | 1, 50, 100   | 1, 50, 100   |
+    -----+--------------+--------------+
+        1|              |              |
+       50|              |              |
+      100|              |              |
+    -----|--------------+--------------+
+        1|              |              |
+       50|              |  WFH         |
+      100|              |              |
+    -----------------------------------+
+    */
+
+
+    QSizeF prefSize = layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(-1, -1));
+    QCOMPARE(prefSize, QSizeF(50+50, 50+50));
+
+    // wfh(1):  = 1
+    QCOMPARE(layout->effectiveSizeHint(Qt::MinimumSize, QSizeF(-1, 2)), QSizeF(1 + 1, 2));
+    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(-1, 2)), QSizeF(50 + 50, 2));
+    QCOMPARE(layout->effectiveSizeHint(Qt::MaximumSize, QSizeF(-1, 2)), QSizeF(100 + 100, 2));
+
+    // wfh(40) = 40
+    QCOMPARE(layout->effectiveSizeHint(Qt::MinimumSize, QSizeF(-1, 80)), QSizeF(1 + 40, 80));
+    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(-1, 80)), QSizeF(50 + 50, 80));
+    QCOMPARE(layout->effectiveSizeHint(Qt::MaximumSize, QSizeF(-1, 80)), QSizeF(100 + 100, 80));
+
+    // wfh(80) = 80
+    QCOMPARE(layout->effectiveSizeHint(Qt::MinimumSize, QSizeF(-1, 160)), QSizeF(1 + 80, 160));
+    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(-1, 160)), QSizeF(50 + 80, 160));
+    QCOMPARE(layout->effectiveSizeHint(Qt::MaximumSize, QSizeF(-1, 160)), QSizeF(100 + 100, 160));
+
+    // wfh(200) = 200
+    QCOMPARE(layout->effectiveSizeHint(Qt::MinimumSize, QSizeF(-1, 300)), QSizeF(1 + 200, 300));
+    QCOMPARE(layout->effectiveSizeHint(Qt::PreferredSize, QSizeF(-1, 300)), QSizeF(50 + 200, 300));
+    QCOMPARE(layout->effectiveSizeHint(Qt::MaximumSize, QSizeF(-1, 300)), QSizeF(100 + 200, 300));
+
+}
 QTEST_MAIN(tst_QGraphicsGridLayout)
 #include "tst_qgraphicsgridlayout.moc"