QGraphicsAnchorLayout: Fix creation of internal layout anchors

Since the AnchorData cleanup commit (c974aca8) all anchor initialization
is being done by refreshSizeHints. However that method was not able
to properly initialize the internal layout anchors.

This commit refactors that method both to add the functionality and
improve readability.

Signed-off-by: Eduardo M. Fleury <eduardo.fleury@openbossa.org>
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@openbossa.org>

2 files changed, 84 insertions, 63 deletions

diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
index 20ff03b..8139b2b 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -92,90 +92,111 @@ qreal QGraphicsAnchorPrivate::spacing() const
 }
 
 
+static void sizeHintsFromItem(QGraphicsLayoutItem *item,
+                             const QGraphicsAnchorLayoutPrivate::Orientation orient,
+                             qreal *minSize, qreal *prefSize,
+                             qreal *expSize, 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.
+    //
+    // Then we check each flag to find the resultant QSizePolicy,
+    // according to the following table:
+    //
+    //      constant               value
+    // QSizePolicy::Fixed            0
+    // QSizePolicy::Minimum       GrowFlag
+    // QSizePolicy::Maximum       ShrinkFlag
+    // QSizePolicy::Preferred     GrowFlag | ShrinkFlag
+    // QSizePolicy::Ignored       GrowFlag | ShrinkFlag | IgnoreFlag
+
+    if (policy & QSizePolicy::ShrinkFlag)
+        *minSize = minSizeHint;
+    else
+        *minSize = prefSizeHint;
+
+    if (policy & QSizePolicy::GrowFlag)
+        *maxSize = maxSizeHint;
+    else
+        *maxSize = prefSizeHint;
+
+    // Note that these two initializations are affected by the previous flags
+    if (policy & QSizePolicy::IgnoreFlag)
+        *prefSize = *maxSize;
+    else
+        *prefSize = prefSizeHint;
+
+    if (policy & QSizePolicy::ExpandFlag)
+        *expSize = *maxSize;
+    else
+        *expSize = *prefSize;
+}
+
 void AnchorData::refreshSizeHints(qreal effectiveSpacing)
 {
-    if (!isLayoutAnchor && (from->m_item == to->m_item)) {
-        QGraphicsLayoutItem *item = from->m_item;
+    const bool isInternalAnchor = from->m_item == to->m_item;
 
-        const QGraphicsAnchorLayoutPrivate::Orientation orient = QGraphicsAnchorLayoutPrivate::edgeOrientation(from->m_edge);
-        const Qt::AnchorPoint centerEdge = QGraphicsAnchorLayoutPrivate::pickEdge(Qt::AnchorHorizontalCenter, orient);
+    if (isInternalAnchor) {
+        const QGraphicsAnchorLayoutPrivate::Orientation orient =
+            QGraphicsAnchorLayoutPrivate::edgeOrientation(from->m_edge);
 
-        QSizePolicy::Policy policy;
-        qreal minSizeHint, prefSizeHint, 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();
+        if (isLayoutAnchor) {
+            minSize = 0;
+            prefSize = 0;
+            expSize = 0;
+            maxSize = QWIDGETSIZE_MAX;
         } else {
-            policy = item->sizePolicy().verticalPolicy();
-            minSizeHint = item->effectiveSizeHint(Qt::MinimumSize).height();
-            prefSizeHint = item->effectiveSizeHint(Qt::PreferredSize).height();
-            maxSizeHint = item->effectiveSizeHint(Qt::MaximumSize).height();
+            QGraphicsLayoutItem *item = from->m_item;
+            sizeHintsFromItem(item, orient, &minSize, &prefSize, &expSize, &maxSize);
         }
-        // minSize, prefSize and maxSize are initialized
-        // with item's preferred Size: this is QSizePolicy::Fixed.
-        //
-        // Then we check each flag to find the resultant QSizePolicy,
-        // according to the following table:
-        //
-        //      constant               value
-        // QSizePolicy::Fixed            0
-        // QSizePolicy::Minimum       GrowFlag
-        // QSizePolicy::Maximum       ShrinkFlag
-        // QSizePolicy::Preferred     GrowFlag | ShrinkFlag
-        // QSizePolicy::Ignored       GrowFlag | ShrinkFlag | IgnoreFlag
-        prefSize = prefSizeHint;
-        minSize = prefSize;
-        maxSize = prefSize;
-
-        if (policy & QSizePolicy::GrowFlag)
-            maxSize = maxSizeHint;
-
-        if (policy & QSizePolicy::ShrinkFlag)
-            minSize = minSizeHint;
-
-        if (policy & QSizePolicy::IgnoreFlag)
-            prefSize = minSize;
 
+        const Qt::AnchorPoint centerEdge =
+            QGraphicsAnchorLayoutPrivate::pickEdge(Qt::AnchorHorizontalCenter, orient);
         bool hasCenter = (from->m_edge == centerEdge || to->m_edge == centerEdge);
 
         if (hasCenter) {
             minSize /= 2;
             prefSize /= 2;
+            expSize /= 2;
             maxSize /= 2;
         }
 
-        if (policy & QSizePolicy::ExpandFlag) {
-            expSize = maxSize;
-        } else {
-            expSize = prefSize;
-        }
-
-        // Set the anchor effective sizes to preferred.
-        //
-        // Note: The idea here is that all items should remain at their
-        // preferred size unless where that's impossible.  In cases where
-        // the item is subject to restrictions (anchored to the layout
-        // edges, for instance), the simplex solver will be run to
-        // recalculate and override the values we set here.
-        sizeAtMinimum = prefSize;
-        sizeAtPreferred = prefSize;
-        sizeAtExpanding = prefSize;
-        sizeAtMaximum = prefSize;
-
     } else if (!hasSize) {
         // Anchor has no size defined, use given default information
         minSize = effectiveSpacing;
         prefSize = effectiveSpacing;
         expSize = effectiveSpacing;
         maxSize = effectiveSpacing;
-
-        sizeAtMinimum = prefSize;
-        sizeAtPreferred = prefSize;
-        sizeAtExpanding = prefSize;
-        sizeAtMaximum = prefSize;
     }
+
+    // Set the anchor effective sizes to preferred.
+    //
+    // Note: The idea here is that all items should remain at their
+    // preferred size unless where that's impossible.  In cases where
+    // the item is subject to restrictions (anchored to the layout
+    // edges, for instance), the simplex solver will be run to
+    // recalculate and override the values we set here.
+    sizeAtMinimum = prefSize;
+    sizeAtPreferred = prefSize;
+    sizeAtExpanding = prefSize;
+    sizeAtMaximum = prefSize;
 }
 
 void ParallelAnchorData::updateChildrenSizes()
diff --git a/tests/auto/qgraphicsanchorlayout/tst_qgraphicsanchorlayout.cpp b/tests/auto/qgraphicsanchorlayout/tst_qgraphicsanchorlayout.cpp
index 4ad48c7..91e5bb3 100644
--- a/tests/auto/qgraphicsanchorlayout/tst_qgraphicsanchorlayout.cpp
+++ b/tests/auto/qgraphicsanchorlayout/tst_qgraphicsanchorlayout.cpp
@@ -1271,7 +1271,7 @@ void tst_QGraphicsAnchorLayout::sizePolicy()
     w1->adjustSize();
 
     QCOMPARE(l->effectiveSizeHint(Qt::MinimumSize), QSizeF(0, 0));
-    QCOMPARE(l->effectiveSizeHint(Qt::PreferredSize), QSizeF(0, 0));
+    QCOMPARE(l->effectiveSizeHint(Qt::PreferredSize), QSizeF(100, 100));
     QCOMPARE(l->effectiveSizeHint(Qt::MaximumSize), QSizeF(100, 100));
 
     delete p;