QGraphicsAnchorLayout: Initial support for Size Policy

In this commit we introduce initial support for Size Policy.
The size policies supported now are:

* QSizePolicy::Fixed
* QSizePolicy::Minimum
* QSizePolicy::Maximum
* QSizePolicy::Preferred
* QSizePolicy::Ignored

Signed-off-by: Anselmo Lacerda S. de Melo <anselmo.melo@openbossa.org>

2 files changed, 39 insertions, 5 deletions

diff --git a/src/gui/graphicsview/qgraphicsanchorlayout.cpp b/src/gui/graphicsview/qgraphicsanchorlayout.cpp
index 12124ab..78b6b53 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout.cpp
+++ b/src/gui/graphicsview/qgraphicsanchorlayout.cpp
@@ -434,7 +434,6 @@ void QGraphicsAnchorLayout::invalidate()
 */
 QSizeF QGraphicsAnchorLayout::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
 {
-    Q_UNUSED(which);
     Q_UNUSED(constraint);
     Q_D(const QGraphicsAnchorLayout);
 
diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
index 23601f9..f7266e2 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -98,17 +98,52 @@ void AnchorData::refreshSizeHints(qreal effectiveSpacing)
         bool hasCenter = false;
         QGraphicsLayoutItem *item = from->m_item;
 
+        QSizePolicy policy = item->sizePolicy();
+
         if (QGraphicsAnchorLayoutPrivate::edgeOrientation(from->m_edge)
             == QGraphicsAnchorLayoutPrivate::Horizontal) {
-            minSize = item->minimumWidth();
+
+            // 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 = item->preferredWidth();
-            maxSize = item->maximumWidth();
+            minSize = prefSize;
+            maxSize = prefSize;
+
+            if (policy.horizontalPolicy() & QSizePolicy::GrowFlag)
+                maxSize = item->maximumWidth();
+
+            if (policy.horizontalPolicy() & QSizePolicy::ShrinkFlag)
+                minSize = item->minimumWidth();
+
+            if (policy.horizontalPolicy() & QSizePolicy::IgnoreFlag)
+                prefSize = minSize;
+
             hasCenter = (from->m_edge == Qt::AnchorHorizontalCenter
                          || to->m_edge == Qt::AnchorHorizontalCenter);
         } else {
-            minSize = item->minimumHeight();
             prefSize = item->preferredHeight();
-            maxSize = item->maximumHeight();
+            minSize = prefSize;
+            maxSize = prefSize;
+
+            if (policy.verticalPolicy() & QSizePolicy::GrowFlag)
+                maxSize = item->maximumHeight();
+
+            if (policy.verticalPolicy() & QSizePolicy::ShrinkFlag)
+                minSize = item->minimumHeight();
+
+            if (policy.verticalPolicy() & QSizePolicy::IgnoreFlag)
+                prefSize = minSize;
+
             hasCenter = (from->m_edge == Qt::AnchorVerticalCenter
                          || to->m_edge == Qt::AnchorVerticalCenter);
         }