Emit grabChanged() from DragHandler and PinchHandler

Followup to ca7cdd71ee33f0d77eb6bf1367d2532e26155cb2 : when overriding
a virtual function, it's good practice to call the base class function,
in the absence of any reason not to.

Fixes: QTBUG-93880
Change-Id: Icbd04faec51d55d8fbf73319bd20f5846761d3d5
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit a10eeee97d42f05409074f69cc99d9a8da5db077)
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

3 files changed, 27 insertions, 1 deletions

diff --git a/src/quick/handlers/qquickmultipointhandler.cpp b/src/quick/handlers/qquickmultipointhandler.cpp
index 4a261f8b87..4f050b70b0 100644
--- a/src/quick/handlers/qquickmultipointhandler.cpp
+++ b/src/quick/handlers/qquickmultipointhandler.cpp
@@ -146,7 +146,7 @@ void QQuickMultiPointHandler::onActiveChanged()
     }
 }
 
-void QQuickMultiPointHandler::onGrabChanged(QQuickPointerHandler *, QQuickEventPoint::GrabTransition transition, QQuickEventPoint *)
+void QQuickMultiPointHandler::onGrabChanged(QQuickPointerHandler *grabber, QQuickEventPoint::GrabTransition transition, QQuickEventPoint *point)
 {
     Q_D(QQuickMultiPointHandler);
     // If another handler or item takes over this set of points, assume it has
@@ -155,6 +155,20 @@ void QQuickMultiPointHandler::onGrabChanged(QQuickPointerHandler *, QQuickEventP
     // (e.g. between DragHandler and PinchHandler).
     if (transition == QQuickEventPoint::UngrabExclusive || transition == QQuickEventPoint::CancelGrabExclusive)
         d->currentPoints.clear();
+    if (grabber != this)
+        return;
+    switch (transition) {
+    case QQuickEventPoint::GrabExclusive:
+    case QQuickEventPoint::GrabPassive:
+    case QQuickEventPoint::UngrabPassive:
+    case QQuickEventPoint::UngrabExclusive:
+    case QQuickEventPoint::CancelGrabPassive:
+    case QQuickEventPoint::CancelGrabExclusive:
+        QQuickPointerHandler::onGrabChanged(grabber, transition, point);
+        break;
+    case QQuickEventPoint::OverrideGrabPassive:
+        return; // don't emit
+    }
 }
 
 QVector<QQuickEventPoint *> QQuickMultiPointHandler::eligiblePoints(QQuickPointerEvent *event)
diff --git a/tests/auto/quick/pointerhandlers/qquickpinchhandler/tst_qquickpinchhandler.cpp b/tests/auto/quick/pointerhandlers/qquickpinchhandler/tst_qquickpinchhandler.cpp
index 19fdae3b44..2b8ddd197d 100644
--- a/tests/auto/quick/pointerhandlers/qquickpinchhandler/tst_qquickpinchhandler.cpp
+++ b/tests/auto/quick/pointerhandlers/qquickpinchhandler/tst_qquickpinchhandler.cpp
@@ -217,6 +217,7 @@ void tst_QQuickPinchHandler::scale()
 
     QQuickPinchHandler *pinchHandler = window->rootObject()->findChild<QQuickPinchHandler*>("pinchHandler");
     QVERIFY(pinchHandler != nullptr);
+    QSignalSpy grabChangedSpy(pinchHandler, SIGNAL(grabChanged(QQuickEventPoint::GrabTransition, QQuickEventPoint*)));
 
     QQuickItem *root = qobject_cast<QQuickItem*>(window->rootObject());
     QVERIFY(root != nullptr);
@@ -238,6 +239,7 @@ void tst_QQuickPinchHandler::scale()
         // it is outside its bounds.
         pinchSequence.stationary(0).press(1, p1, window).commit();
         QQuickTouchUtils::flush(window);
+        QTRY_COMPARE(grabChangedSpy.count(), 1); // passive grab
 
         QPoint pd(10, 10);
         // move one point until PinchHandler activates
@@ -247,6 +249,8 @@ void tst_QQuickPinchHandler::scale()
             QQuickTouchUtils::flush(window);
         }
         QCOMPARE(pinchHandler->active(), true);
+        // first point got a passive grab; both points got exclusive grabs
+        QCOMPARE(grabChangedSpy.count(), 3);
         QLineF line(p0, p1);
         const qreal startLength = line.length();
 
diff --git a/tests/manual/pointer/pinchHandler.qml b/tests/manual/pointer/pinchHandler.qml
index 46ab91c2ed..93169da60a 100644
--- a/tests/manual/pointer/pinchHandler.qml
+++ b/tests/manual/pointer/pinchHandler.qml
@@ -154,6 +154,14 @@ Rectangle {
                         if (!active)
                             anim.restart(centroid.velocity)
                     }
+                    onGrabChanged: function (transition, point) {
+                        if (transition === 0x10) { // GrabExclusive
+                            console.log(point.id, "grabbed @", point.position)
+                            Qt.createQmlObject("import QtQuick 2.0; Rectangle { opacity: 0.5; border.color: 'red'; radius: 8; width: radius * 2; height: radius * 2; " +
+                                               "x: " + (point.position.x - 8) + "; y: " + (point.position.y - 8) + "}",
+                                               rect3, "touchpoint" + point.id);
+                        }
+                    }
                 }
                 TapHandler { gesturePolicy: TapHandler.DragThreshold; onTapped: rect3.z = rect2.z + 1 }
                 MomentumAnimation { id: anim; target: rect3 }