TapHandler: wait until after tapped is emitted to reset point.position

We don't want it to hold its position indefinitely after the button is
released.  But in practice, reset() gets called again anyway in
QQuickSinglePointHandler::handlePointerEventImpl(), _after_
handleEventPoint(), which means after tapped() is emitted.  Having the
point hold its position that much longer is convenient for applications
and more consistent with the state expressed by the release event.
Also amend the documentation.
Partially reverts 17237efaefabe924599abe00e92d8b54032d7915

[ChangeLog][Event Handlers][Important Behavior Changes] TapHandler.point now
holds the release position while the tapped() signal is emitted.

Fixes: QTBUG-76871
Task-number: QTBUG-64847
Change-Id: I621a2eba4507a498788e9384344e8b4b7da32403
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

4 files changed, 15 insertions, 19 deletions

diff --git a/src/quick/handlers/qquickhandlerpoint.cpp b/src/quick/handlers/qquickhandlerpoint.cpp
index de21537f27..f3d92cf200 100644
--- a/src/quick/handlers/qquickhandlerpoint.cpp
+++ b/src/quick/handlers/qquickhandlerpoint.cpp
@@ -51,13 +51,14 @@ Q_DECLARE_LOGGING_CATEGORY(DBG_TOUCH_TARGET)
 
     A QML representation of a QQuickEventPoint.
 
-    It's possible to make bindings to properties of a \l SinglePointHandler's
-    current point. For example:
+    It's possible to make bindings to properties of a handler's current
+    \l {SinglePointHandler::point}{point} or
+    \l {MultiPointHandler::centroid}{centroid}. For example:
 
     \snippet pointerHandlers/dragHandlerNullTarget.qml 0
 
     The point is kept up-to-date when the DragHandler is actively responding to
-    an EventPoint; but when the point is released, or the current point is
+    an EventPoint; but after the point is released, or when the current point is
     being handled by a different handler, \c position.x and \c position.y are 0.
 
     \note This is practically identical to QtQuick::EventPoint; however an
@@ -68,7 +69,7 @@ Q_DECLARE_LOGGING_CATEGORY(DBG_TOUCH_TARGET)
     handler is handling. HandlerPoint is a Q_GADGET that the handler owns.
     This allows you to make lifetime bindings to its properties.
 
-    \sa SinglePointHandler::point
+    \sa SinglePointHandler::point, MultiPointHandler::centroid
 */
 
 QQuickHandlerPoint::QQuickHandlerPoint()
@@ -106,12 +107,6 @@ void QQuickHandlerPoint::reset(const QQuickEventPoint *point)
         m_scenePressPosition = point->scenePosition();
         m_pressedButtons = event->buttons();
         break;
-    case QQuickEventPoint::Released:
-        if (event->buttons() == Qt::NoButton) {
-            reset();
-            return;
-        }
-        break;
     default:
         break;
     }
diff --git a/src/quick/handlers/qquicktaphandler.cpp b/src/quick/handlers/qquicktaphandler.cpp
index 73c559c998..61f97868e8 100644
--- a/src/quick/handlers/qquicktaphandler.cpp
+++ b/src/quick/handlers/qquicktaphandler.cpp
@@ -391,9 +391,6 @@ void QQuickTapHandler::updateTimeHeld()
     from the release event about the point that was tapped:
 
     \snippet pointerHandlers/tapHandlerOnTapped.qml 0
-
-    \note At the time this signal is emitted, \l point has been reset
-    (all coordinates are \c 0).
 */
 
 /*!
@@ -405,9 +402,6 @@ void QQuickTapHandler::updateTimeHeld()
     it can be tapped again; but if the time until the next tap is less,
     \l tapCount will increase. The \c eventPoint signal parameter contains
     information from the release event about the point that was tapped.
-
-    \note At the time this signal is emitted, \l point has been reset
-    (all coordinates are \c 0).
 */
 
 /*!
@@ -421,9 +415,6 @@ void QQuickTapHandler::updateTimeHeld()
     \l singleTapped, \l tapped, and \l tapCountChanged. The \c eventPoint
     signal parameter contains information from the release event about the
     point that was tapped.
-
-    \note At the time this signal is emitted, \l point has been reset
-    (all coordinates are \c 0).
 */
 
 /*!
diff --git a/tests/auto/quick/pointerhandlers/qquicktaphandler/data/Button.qml b/tests/auto/quick/pointerhandlers/qquicktaphandler/data/Button.qml
index 221e7df139..042b730799 100644
--- a/tests/auto/quick/pointerhandlers/qquicktaphandler/data/Button.qml
+++ b/tests/auto/quick/pointerhandlers/qquicktaphandler/data/Button.qml
@@ -34,6 +34,7 @@ Rectangle {
     property alias pressed: tap.pressed
     property bool checked: false
     property alias gesturePolicy: tap.gesturePolicy
+    property point tappedPosition: Qt.point(0, 0)
     signal tapped
     signal canceled
 
@@ -51,6 +52,7 @@ Rectangle {
         longPressThreshold: 100 // CI can be insanely slow, so don't demand a timely release to generate onTapped
         onTapped: {
             tapFlash.start()
+            root.tappedPosition = point.scenePosition
             root.tapped()
         }
         onCanceled: root.canceled()
diff --git a/tests/auto/quick/pointerhandlers/qquicktaphandler/tst_qquicktaphandler.cpp b/tests/auto/quick/pointerhandlers/qquicktaphandler/tst_qquicktaphandler.cpp
index 33cea69147..e77ea97518 100644
--- a/tests/auto/quick/pointerhandlers/qquicktaphandler/tst_qquicktaphandler.cpp
+++ b/tests/auto/quick/pointerhandlers/qquicktaphandler/tst_qquicktaphandler.cpp
@@ -107,6 +107,8 @@ void tst_TapHandler::touchGesturePolicyDragThreshold()
 
     QQuickItem *buttonDragThreshold = window->rootObject()->findChild<QQuickItem*>("DragThreshold");
     QVERIFY(buttonDragThreshold);
+    QQuickTapHandler *tapHandler = buttonDragThreshold->findChild<QQuickTapHandler*>();
+    QVERIFY(tapHandler);
     QSignalSpy dragThresholdTappedSpy(buttonDragThreshold, SIGNAL(tapped()));
 
     // DragThreshold button stays pressed while touchpoint stays within dragThreshold, emits tapped on release
@@ -122,6 +124,8 @@ void tst_TapHandler::touchGesturePolicyDragThreshold()
     QQuickTouchUtils::flush(window);
     QTRY_VERIFY(!buttonDragThreshold->property("pressed").toBool());
     QCOMPARE(dragThresholdTappedSpy.count(), 1);
+    QCOMPARE(buttonDragThreshold->property("tappedPosition").toPoint(), p1);
+    QCOMPARE(tapHandler->point().position(), QPointF());
 
     // DragThreshold button is no longer pressed if touchpoint goes beyond dragThreshold
     dragThresholdTappedSpy.clear();
@@ -152,6 +156,8 @@ void tst_TapHandler::mouseGesturePolicyDragThreshold()
 
     QQuickItem *buttonDragThreshold = window->rootObject()->findChild<QQuickItem*>("DragThreshold");
     QVERIFY(buttonDragThreshold);
+    QQuickTapHandler *tapHandler = buttonDragThreshold->findChild<QQuickTapHandler*>();
+    QVERIFY(tapHandler);
     QSignalSpy dragThresholdTappedSpy(buttonDragThreshold, SIGNAL(tapped()));
 
     // DragThreshold button stays pressed while mouse stays within dragThreshold, emits tapped on release
@@ -164,6 +170,8 @@ void tst_TapHandler::mouseGesturePolicyDragThreshold()
     QTest::mouseRelease(window, Qt::LeftButton, Qt::NoModifier, p1);
     QTRY_VERIFY(!buttonDragThreshold->property("pressed").toBool());
     QTRY_COMPARE(dragThresholdTappedSpy.count(), 1);
+    QCOMPARE(buttonDragThreshold->property("tappedPosition").toPoint(), p1);
+    QCOMPARE(tapHandler->point().position(), QPointF());
 
     // DragThreshold button is no longer pressed if mouse goes beyond dragThreshold
     dragThresholdTappedSpy.clear();