MouseArea: use current value of drag.axis

If the drag.axis is changed while a drag operation is in progress, put
it into action immediately. This allows, for example, start a dragging
operation out of an item in a scrollable ListView to anywhere on the
screen.
See the linked bug number for an example.

Task-number: QTBUG-26440
Change-Id: I4ffa71c08b97a767aec7f69d19271000a2631327
Reviewed-by: Rick Stockton <rickstockton@reno-computerhelp.com>
Reviewed-by: Andrew den Exter <andrew.den-exter@nokia.com>

4 files changed, 109 insertions, 11 deletions

diff --git a/src/declarative/graphicsitems/qdeclarativemousearea.cpp b/src/declarative/graphicsitems/qdeclarativemousearea.cpp
index c653893..60d86bb 100644
--- a/src/declarative/graphicsitems/qdeclarativemousearea.cpp
+++ b/src/declarative/graphicsitems/qdeclarativemousearea.cpp
@@ -483,10 +483,6 @@ void QDeclarativeMouseArea::mousePressEvent(QGraphicsSceneMouseEvent *event)
     else {
         d->longPress = false;
         d->saveEvent(event);
-        if (d->drag) {
-            d->dragX = drag()->axis() & QDeclarativeDrag::XAxis;
-            d->dragY = drag()->axis() & QDeclarativeDrag::YAxis;
-        }
         if (d->drag)
             d->drag->setActive(false);
         setHovered(true);
@@ -540,7 +536,10 @@ void QDeclarativeMouseArea::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
         if (keepMouseGrab() && d->stealMouse)
             d->drag->setActive(true);
 
-        if (d->dragX && d->drag->active()) {
+        bool dragX = drag()->axis() & QDeclarativeDrag::XAxis;
+        bool dragY = drag()->axis() & QDeclarativeDrag::YAxis;
+
+        if (dragX && d->drag->active()) {
             qreal x = (curLocalPos.x() - startLocalPos.x()) + d->startX;
             if (x < drag()->xmin())
                 x = drag()->xmin();
@@ -548,7 +547,7 @@ void QDeclarativeMouseArea::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
                 x = drag()->xmax();
             drag()->target()->setX(x);
         }
-        if (d->dragY && d->drag->active()) {
+        if (dragY && d->drag->active()) {
             qreal y = (curLocalPos.y() - startLocalPos.y()) + d->startY;
             if (y < drag()->ymin())
                 y = drag()->ymin();
@@ -558,9 +557,9 @@ void QDeclarativeMouseArea::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
         }
 
         if (!keepMouseGrab()) {
-            if ((!d->dragY && dy < dragThreshold && d->dragX && dx > dragThreshold)
-                || (!d->dragX && dx < dragThreshold && d->dragY && dy > dragThreshold)
-                || (d->dragX && d->dragY && (dx > dragThreshold || dy > dragThreshold))) {
+            if ((!dragY && dy < dragThreshold && dragX && dx > dragThreshold)
+                || (!dragX && dx < dragThreshold && dragY && dy > dragThreshold)
+                || (dragX && dragY && (dx > dragThreshold || dy > dragThreshold))) {
                 setKeepMouseGrab(true);
                 d->stealMouse = true;
             }
diff --git a/src/declarative/graphicsitems/qdeclarativemousearea_p_p.h b/src/declarative/graphicsitems/qdeclarativemousearea_p_p.h
index 00c6eed..de34565 100644
--- a/src/declarative/graphicsitems/qdeclarativemousearea_p_p.h
+++ b/src/declarative/graphicsitems/qdeclarativemousearea_p_p.h
@@ -106,8 +106,6 @@ public:
     bool pressed : 1;
     bool longPress : 1;
     bool moved : 1;
-    bool dragX : 1;
-    bool dragY : 1;
     bool stealMouse : 1;
     bool doubleClick : 1;
     bool preventStealing : 1;
diff --git a/tests/auto/declarative/qdeclarativemousearea/data/changeAxis.qml b/tests/auto/declarative/qdeclarativemousearea/data/changeAxis.qml
new file mode 100644
index 0000000..e0b11a3
--- /dev/null
+++ b/tests/auto/declarative/qdeclarativemousearea/data/changeAxis.qml
@@ -0,0 +1,22 @@
+import QtQuick 1.0
+Rectangle {
+    id: whiteRect
+    width: 200
+    height: 200
+    color: "white"
+    Rectangle {
+        id: blackRect
+        objectName: "blackrect"
+        color: "black"
+        y: 50
+        x: 50
+        width: 100
+        height: 100
+        MouseArea {
+            objectName: "mouseregion"
+            anchors.fill: parent
+            drag.target: blackRect
+            drag.axis: blackRect.x <= 60 ? Drag.XandYAxis : Drag.YAxis
+         }
+     }
+ }
diff --git a/tests/auto/declarative/qdeclarativemousearea/tst_qdeclarativemousearea.cpp b/tests/auto/declarative/qdeclarativemousearea/tst_qdeclarativemousearea.cpp
index 98158e2..fcd9e09 100644
--- a/tests/auto/declarative/qdeclarativemousearea/tst_qdeclarativemousearea.cpp
+++ b/tests/auto/declarative/qdeclarativemousearea/tst_qdeclarativemousearea.cpp
@@ -74,6 +74,7 @@ private slots:
 #ifndef QT_NO_CONTEXTMENU
     void preventContextMenu();
 #endif // QT_NO_CONTEXTMENU
+    void changeAxis();
 
 private:
     QDeclarativeView *createView();
@@ -701,6 +702,84 @@ void tst_QDeclarativeMouseArea::preventContextMenu()
 }
 #endif // QT_NO_CONTEXTMENU
 
+void tst_QDeclarativeMouseArea::changeAxis()
+{
+    QDeclarativeView *canvas = createView();
+
+    canvas->setSource(QUrl::fromLocalFile(SRCDIR "/data/changeAxis.qml"));
+    canvas->show();
+    canvas->setFocus();
+    QVERIFY(canvas->rootObject() != 0);
+
+    QDeclarativeMouseArea *mouseRegion = canvas->rootObject()->findChild<QDeclarativeMouseArea*>("mouseregion");
+    QDeclarativeDrag *drag = mouseRegion->drag();
+    QVERIFY(mouseRegion != 0);
+    QVERIFY(drag != 0);
+
+    // target
+    QDeclarativeItem *blackRect = canvas->rootObject()->findChild<QDeclarativeItem*>("blackrect");
+    QVERIFY(blackRect != 0);
+    QVERIFY(blackRect == drag->target());
+
+    QVERIFY(!drag->active());
+
+    // Start a diagonal drag
+    QGraphicsScene *scene = canvas->scene();
+    QGraphicsSceneMouseEvent pressEvent(QEvent::GraphicsSceneMousePress);
+    pressEvent.setScenePos(QPointF(100, 100));
+    pressEvent.setButton(Qt::LeftButton);
+    pressEvent.setButtons(Qt::LeftButton);
+    QApplication::sendEvent(scene, &pressEvent);
+
+    QGraphicsSceneMouseEvent moveEvent(QEvent::GraphicsSceneMouseMove);
+    moveEvent.setScenePos(QPointF(106, 106));
+    moveEvent.setButton(Qt::LeftButton);
+    moveEvent.setButtons(Qt::LeftButton);
+    QApplication::sendEvent(scene, &moveEvent);
+
+    moveEvent.setScenePos(QPointF(110, 110));
+    moveEvent.setButton(Qt::LeftButton);
+    moveEvent.setButtons(Qt::LeftButton);
+    QApplication::sendEvent(scene, &moveEvent);
+
+    QVERIFY(drag->active());
+    QCOMPARE(blackRect->x(), 60.0);
+    QCOMPARE(blackRect->y(), 60.0);
+    QCOMPARE(drag->axis(), QDeclarativeDrag::XandYAxis);
+
+    /* When blackRect.x becomes bigger than 60, the drag axis is change to
+     * Drag.YAxis by the QML code. Verify that this happens, and that the drag
+     * movement is effectively constrained to the Y axis. */
+    moveEvent.setScenePos(QPointF(115, 115));
+    moveEvent.setButton(Qt::LeftButton);
+    moveEvent.setButtons(Qt::LeftButton);
+    QApplication::sendEvent(scene, &moveEvent);
+
+    QCOMPARE(blackRect->x(), 65.0);
+    QCOMPARE(blackRect->y(), 65.0);
+    QCOMPARE(drag->axis(), QDeclarativeDrag::YAxis);
+
+    moveEvent.setScenePos(QPointF(120, 120));
+    moveEvent.setButton(Qt::LeftButton);
+    moveEvent.setButtons(Qt::LeftButton);
+    QApplication::sendEvent(scene, &moveEvent);
+
+    QCOMPARE(blackRect->x(), 65.0);
+    QCOMPARE(blackRect->y(), 70.0);
+
+    QGraphicsSceneMouseEvent releaseEvent(QEvent::GraphicsSceneMouseRelease);
+    releaseEvent.setScenePos(QPointF(120, 120));
+    releaseEvent.setButton(Qt::LeftButton);
+    releaseEvent.setButtons(Qt::LeftButton);
+    QApplication::sendEvent(scene, &releaseEvent);
+
+    QVERIFY(!drag->active());
+    QCOMPARE(blackRect->x(), 65.0);
+    QCOMPARE(blackRect->y(), 70.0);
+
+    delete canvas;
+}
+
 QTEST_MAIN(tst_QDeclarativeMouseArea)
 
 #include "tst_qdeclarativemousearea.moc"