Decide whether to synthesize mouse events on a per device basis

Currently Qt uses the QPlatformIntegration::StyleHint
SynthesizeMouseFromTouchEvents to check whether to synthesize mouse
events from touch events. But not only platform plugins can produce
touch events, they can be created by e.g. QTest::touchEvent() and in
this case we almost definitely need synthesizing regardless of the
platform.

This commit introduces a QTouchDevice::MouseEmulation capability which
replaces use of the QPlatformIntegration::SynthesizeMouseFromTouchEvents.
So it's possible to pass QTouchDevice without this capability to
QTest::touchEvent() and be sure that mouse events will be synthesized.
Notice that touch pads always emulate mouse events.
As a result we can activate some tests which were disabled for specific
platform configurations by commits 6c1670d8c273819435867c42725c0db0eee597dc
and e9760f1559361c39f269fb89f1ebd01f6ee8378d.

Change-Id: Idc82fa4007a095fc1cb5934979361b0023d2b793
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>

1 files changed, 3 insertions, 9 deletions

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 0d5a130dfd..61addab9d6 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -788,12 +788,6 @@ bool QGuiApplicationPrivate::isWindowBlocked(QWindow *window, QWindow **blocking
     return false;
 }
 
-bool QGuiApplicationPrivate::synthesizeMouseFromTouchEventsEnabled()
-{
-    return QCoreApplication::testAttribute(Qt::AA_SynthesizeMouseForUnhandledTouchEvents)
-            && QGuiApplicationPrivate::platformIntegration()->styleHint(QPlatformIntegration::SynthesizeMouseFromTouchEvents).toBool();
-}
-
 /*!
     Returns the QWindow that receives events tied to focus,
     such as key events.
@@ -2423,9 +2417,9 @@ void QGuiApplicationPrivate::processTouchEvent(QWindowSystemInterfacePrivate::To
         }
 
         QGuiApplication::sendSpontaneousEvent(w, &touchEvent);
-        if (!e->synthetic() && !touchEvent.isAccepted() && synthesizeMouseFromTouchEventsEnabled()) {
-            // exclude touchpads as those generate their own mouse events
-            if (touchEvent.device()->type() != QTouchDevice::TouchPad) {
+        if (!e->synthetic() && !touchEvent.isAccepted() && qApp->testAttribute(Qt::AA_SynthesizeMouseForUnhandledTouchEvents)) {
+            // exclude devices which generate their own mouse events
+            if (!(touchEvent.device()->capabilities() & QTouchDevice::MouseEmulation)) {
                 Qt::MouseButtons b = eventType == QEvent::TouchEnd ? Qt::NoButton : Qt::LeftButton;
                 if (b == Qt::NoButton)
                     self->synthesizedMousePoints.clear();