QQuickWindow: obey AA_SynthesizeMouseForUnhandledTouchEvents

Until now, AA_SynthesizeMouseForUnhandledTouchEvents has only affected
behavior of QGuiApplicationPrivate::processTouchEvent, but had no
effect in Qt Quick.  QQuickWindow also accepts the touch event
just to make sure that QGuiApplication will not synthesize mouse
from touch, because it would be redundant: QQuickWindow does that
for itself.

Now we make it have an effect in Qt Quick too: skip mouse synthesis
if it is set to false.  This provides a way to simplify the
event delivery.  If you set it false, then you cannot manipulate old
mouse-only items like MouseArea and Flickable on a touchscreen.
(You can of course use event handlers for that.)

[ChangeLog][QtQuick][QQuickWindow] You can now disable touch->mouse
event synthesis in QtQuick by calling
qGuiApp.setAttribute(Qt::AA_SynthesizeMouseForUnhandledTouchEvents, false);
This will simplify and speed up event delivery, and it will also prevent
any and all interaction with mouse-only items like MouseArea and
Flickable on a touchscreen.

Task-number: QTBUG-52748
Change-Id: I71f1731b5abaeabd9dbce1112cd23bc97d24c12a
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

1 files changed, 2 insertions, 2 deletions

diff --git a/tests/auto/quickwidgets/qquickwidget/tst_qquickwidget.cpp b/tests/auto/quickwidgets/qquickwidget/tst_qquickwidget.cpp
index af358925fe..e523274d0a 100644
--- a/tests/auto/quickwidgets/qquickwidget/tst_qquickwidget.cpp
+++ b/tests/auto/quickwidgets/qquickwidget/tst_qquickwidget.cpp
@@ -614,8 +614,8 @@ void tst_qquickwidget::synthMouseFromTouch()
     QTest::touchEvent(&window, device).move(0, p2, &window);
     QTest::touchEvent(&window, device).release(0, p2, &window);
 
-    QCOMPARE(item->m_touchEvents.count(), 3);
-    QCOMPARE(item->m_mouseEvents.count(), acceptTouch ? 0 : 3);
+    QCOMPARE(item->m_touchEvents.count(), !synthMouse && !acceptTouch ? 1 : 3);
+    QCOMPARE(item->m_mouseEvents.count(), (acceptTouch || !synthMouse) ? 0 : 3);
     QCOMPARE(childView->m_mouseEvents.count(), 0);
     for (const QMouseEvent &ev : item->m_mouseEvents)
         QCOMPARE(ev.source(), Qt::MouseEventSynthesizedByQt);