Transforms do not obey AnchorUnderMouse with viewport margins set

setTransformationAnchor(QGraphicsView::AnchorUnderMouse) would not work
properly if viewport margins were set. When centering the view in
QGraphicsViewPrivate::centerView, the viewport margins were not being taken
into account.

Mapping from global cursor coordinates in the viewport instead of the view
fixes the issue.

Task-number: 255529
Reviewed-by: Olivier

2 files changed, 39 insertions, 2 deletions

diff --git a/src/gui/graphicsview/qgraphicsview.cpp b/src/gui/graphicsview/qgraphicsview.cpp
index 7213542..91e654c 100644
--- a/src/gui/graphicsview/qgraphicsview.cpp
+++ b/src/gui/graphicsview/qgraphicsview.cpp
@@ -493,8 +493,8 @@ void QGraphicsViewPrivate::centerView(QGraphicsView::ViewportAnchor anchor)
             // Last scene pos: lastMouseMoveScenePoint
             // Current mouse pos:
             QPointF transformationDiff = q->mapToScene(viewport->rect().center())
-                                         - q->mapToScene(q->mapFromGlobal(QCursor::pos()));
-            q->centerOn(lastMouseMoveScenePoint + transformationDiff);;
+                                         - q->mapToScene(viewport->mapFromGlobal(QCursor::pos()));
+            q->centerOn(lastMouseMoveScenePoint + transformationDiff);
         } else {
             q->centerOn(lastCenterPoint);
         }
diff --git a/tests/auto/qgraphicsview/tst_qgraphicsview.cpp b/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
index 0c65b87..c12fb11 100644
--- a/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
+++ b/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
@@ -216,6 +216,7 @@ private slots:
     void task239047_fitInViewSmallViewport();
     void task245469_itemsAtPointWithClip();
     void task253415_reconnectUpdateSceneOnSceneChanged();
+    void task255529_transformationAnchorMouseAndViewportMargins();
 };
 
 void tst_QGraphicsView::initTestCase()
@@ -3617,5 +3618,41 @@ void tst_QGraphicsView::task253415_reconnectUpdateSceneOnSceneChanged()
     QVERIFY(wasConnected2);
 }
 
+void tst_QGraphicsView::task255529_transformationAnchorMouseAndViewportMargins()
+{
+    QGraphicsScene scene(-100, -100, 200, 200);
+    scene.addRect(QRectF(-50, -50, 100, 100), QPen(Qt::black), QBrush(Qt::blue));
+
+    class VpGraphicsView: public QGraphicsView
+    {
+    public:
+        VpGraphicsView(QGraphicsScene *scene)
+            : QGraphicsView(scene)
+        {
+            setViewportMargins(8, 16, 12, 20);
+            setTransformationAnchor(QGraphicsView::AnchorUnderMouse);
+            setMouseTracking(true);
+        }
+    };
+
+    VpGraphicsView view(&scene);
+    view.show();
+    QPoint mouseViewPos(20, 20);
+    sendMouseMove(view.viewport(), mouseViewPos);
+    QTest::qWait(125);
+
+    QPointF mouseScenePos = view.mapToScene(mouseViewPos);
+    view.setTransform(QTransform().scale(5, 5));
+    QTest::qWait(125);
+    view.setTransform(QTransform().rotate(5, Qt::ZAxis), true);
+    QTest::qWait(125);
+
+    QPointF newMouseScenePos = view.mapToScene(mouseViewPos);
+    qreal slack = 3;
+    QVERIFY(qAbs(newMouseScenePos.x() - mouseScenePos.x()) < slack);
+    QVERIFY(qAbs(newMouseScenePos.y() - mouseScenePos.y()) < slack);
+}
+
+
 QTEST_MAIN(tst_QGraphicsView)
 #include "tst_qgraphicsview.moc"