QGraphicsAnchorLayout: Fix center anchor deletion logic

We were missing a call to "removeCenterAnchors" in the "removeAnchors"
method. To solve that, and also reduce the number of useless calls to
that method, this commit:

1) Calls it only from "removeInternalVertex"
2) Does some preliminary testing before calling it
3) Replace the former test inside "removeCenterAnchors" by a Q_ASSERT

It also adds other Q_ASSERTs to protect us from regression bugs.

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

2 files changed, 12 insertions, 9 deletions

diff --git a/src/gui/graphicsview/qgraphicsanchorlayout.cpp b/src/gui/graphicsview/qgraphicsanchorlayout.cpp
index fe335e8..6360e75 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout.cpp
+++ b/src/gui/graphicsview/qgraphicsanchorlayout.cpp
@@ -200,9 +200,6 @@ void QGraphicsAnchorLayout::removeAnchor(QGraphicsLayoutItem *firstItem, Edge fi
     }
 
     d->removeAnchor(firstItem, firstEdge, secondItem, secondEdge);
-    d->removeCenterAnchors(firstItem, firstEdge);
-    d->removeCenterAnchors(secondItem, secondEdge);
-
     invalidate();
 }
 
diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
index 7516c06..afe60a1 100644
--- a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -456,6 +456,9 @@ void QGraphicsAnchorLayoutPrivate::deleteLayoutEdges()
 {
     Q_Q(QGraphicsAnchorLayout);
 
+    Q_ASSERT(internalVertex(q, QGraphicsAnchorLayout::HCenter) == NULL);
+    Q_ASSERT(internalVertex(q, QGraphicsAnchorLayout::VCenter) == NULL);
+
     removeAnchor(q, QGraphicsAnchorLayout::Left, q, QGraphicsAnchorLayout::Right);
     removeAnchor(q, QGraphicsAnchorLayout::Top, q, QGraphicsAnchorLayout::Bottom);
 }
@@ -568,11 +571,6 @@ void QGraphicsAnchorLayoutPrivate::removeCenterAnchors(
         return;
     }
 
-    // Check if vertex is used by other than the internal anchors
-    AnchorVertex *center = internalVertex(item, centerEdge);
-    if (graph[orientation].adjacentVertices(center).count() > 2)
-        return;
-
     // Orientation code
     QGraphicsAnchorLayout::Edge firstEdge;
     QGraphicsAnchorLayout::Edge lastEdge;
@@ -586,8 +584,10 @@ void QGraphicsAnchorLayoutPrivate::removeCenterAnchors(
     }
 
     AnchorVertex *first = internalVertex(item, firstEdge);
+    AnchorVertex *center = internalVertex(item, centerEdge);
     AnchorVertex *last = internalVertex(item, lastEdge);
-    Q_ASSERT(first && last);
+    Q_ASSERT(first && center && last);
+    Q_ASSERT(graph[orientation].adjacentVertices(center).count() == 2);
 
     // Create new anchor
     AnchorData *oldData = graph[orientation].edgeData(first, center);
@@ -792,6 +792,12 @@ void QGraphicsAnchorLayoutPrivate::removeInternalVertex(QGraphicsLayoutItem *ite
     } else {
         // Update reference count
         m_vertexList.insert(pair, v);
+
+        if ((v.second == 2) &&
+            ((edge == QGraphicsAnchorLayout::HCenter) ||
+             (edge == QGraphicsAnchorLayout::VCenter))) {
+            removeCenterAnchors(item, edge);
+        }
     }
 }