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 6c1670d8c2
and e9760f1559.

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

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()) {
+        if (!e->synthetic() && !touchEvent.isAccepted() && qApp->testAttribute(Qt::AA_SynthesizeMouseForUnhandledTouchEvents)) {
-            // exclude touchpads as those generate their own mouse events
+            // exclude devices which generate their own mouse events
-            if (touchEvent.device()->type() != QTouchDevice::TouchPad) {
+            if (!(touchEvent.device()->capabilities() & QTouchDevice::MouseEmulation)) {
                 Qt::MouseButtons b = eventType == QEvent::TouchEnd ? Qt::NoButton : Qt::LeftButton;
                 if (b == Qt::NoButton)
                     self->synthesizedMousePoints.clear();

src/gui/kernel/qguiapplication_p.h

@@ -190,8 +190,6 @@ public:
     static void updateBlockedStatus(QWindow *window);
     virtual bool isWindowBlocked(QWindow *window, QWindow **blockingWindow = 0) const;
 
-    static bool synthesizeMouseFromTouchEventsEnabled();
-
     static Qt::MouseButtons buttons;
     static ulong mousePressTime;
     static Qt::MouseButton mousePressButton;

src/gui/kernel/qplatformintegration.cpp

@@ -386,8 +386,6 @@ QVariant QPlatformIntegration::styleHint(StyleHint hint) const
         return QPlatformTheme::defaultThemeHint(QPlatformTheme::StartDragVelocity);
     case UseRtlExtensions:
         return QVariant(false);
-    case SynthesizeMouseFromTouchEvents:
-        return true;
     case SetFocusOnTouchRelease:
         return QVariant(false);
     case MousePressAndHoldInterval:

src/gui/kernel/qplatformintegration.h

@@ -141,7 +141,6 @@ public:
         FontSmoothingGamma,
         StartDragVelocity,
         UseRtlExtensions,
-        SynthesizeMouseFromTouchEvents,
         PasswordMaskCharacter,
         SetFocusOnTouchRelease,
         ShowIsMaximized,

src/gui/kernel/qtouchdevice.cpp

@@ -96,6 +96,9 @@ QT_BEGIN_NAMESPACE
 
     \value NormalizedPosition Indicates that the normalized position is available, meaning that normalizedPos()
                               returns a valid value.
+
+    \value MouseEmulation Indicates that the device synthesizes mouse events.
+                          This enum value has been introduced in Qt 5.5.
 */
 
 /*!

src/gui/kernel/qtouchdevice.h

@@ -55,7 +55,8 @@ public:
         Pressure = 0x0004,
         Velocity = 0x0008,
         RawPositions = 0x0010,
-        NormalizedPosition = 0x0020
+        NormalizedPosition = 0x0020,
+        MouseEmulation = 0x0040
     };
     Q_DECLARE_FLAGS(Capabilities, CapabilityFlag)
 

src/plugins/platforms/cocoa/qcocoaintegration.mm

@@ -505,8 +505,6 @@ QVariant QCocoaIntegration::styleHint(StyleHint hint) const
 {
     if (hint == QPlatformIntegration::FontSmoothingGamma)
         return 2.0;
-    if (hint == QPlatformIntegration::SynthesizeMouseFromTouchEvents)
-        return false;
 
     return QPlatformIntegration::styleHint(hint);
 }

src/plugins/platforms/cocoa/qnsview.mm

@@ -157,7 +157,7 @@ static NSString *_q_NSWindowDidChangeOcclusionStateNotification = nil;
         if (!touchDevice) {
             touchDevice = new QTouchDevice;
             touchDevice->setType(QTouchDevice::TouchPad);
-            touchDevice->setCapabilities(QTouchDevice::Position | QTouchDevice::NormalizedPosition);
+            touchDevice->setCapabilities(QTouchDevice::Position | QTouchDevice::NormalizedPosition | QTouchDevice::MouseEmulation);
             QWindowSystemInterface::registerTouchDevice(touchDevice);
         }
     }

src/plugins/platforms/windows/qwindowscontext.cpp

@@ -1235,6 +1235,11 @@ void QWindowsContext::setAsyncExpose(bool value)
     d->m_asyncExpose = value;
 }
 
+QTouchDevice *QWindowsContext::touchDevice() const
+{
+    return d->m_mouseHandler.touchDevice();
+}
+
 /*!
     \brief Windows functions for actual windows.
 

src/plugins/platforms/windows/qwindowscontext.h

@@ -67,6 +67,7 @@ struct QWindowCreationContext;
 struct QWindowsContextPrivate;
 class QPoint;
 class QKeyEvent;
+class QTouchDevice;
 
 #ifndef Q_OS_WINCE
 struct QWindowsUser32DLL
@@ -219,6 +220,8 @@ public:
     bool asyncExpose() const;
     void setAsyncExpose(bool value);
 
+    QTouchDevice *touchDevice() const;
+
 private:
     void handleFocusEvent(QtWindows::WindowsEventType et, QWindowsWindow *w);
 #ifndef QT_NO_CONTEXTMENU

src/plugins/platforms/windows/qwindowsintegration.cpp

@@ -227,6 +227,18 @@ QWindowsIntegrationPrivate::QWindowsIntegrationPrivate(const QStringList &paramL
     qCDebug(lcQpaWindows)
         << __FUNCTION__ << "DpiAwareness=" << dpiAwareness <<",Scaling="
         << QWindowsScaling::factor();
+
+    QTouchDevice *touchDevice = m_context.touchDevice();
+    if (touchDevice) {
+#ifdef Q_OS_WINCE
+        touchDevice->setCapabilities(touchDevice->capabilities() | QTouchDevice::MouseEmulation);
+#else
+        if (!(m_options & QWindowsIntegration::DontPassOsMouseEventsSynthesizedFromTouch)) {
+            touchDevice->setCapabilities(touchDevice->capabilities() | QTouchDevice::MouseEmulation);
+        }
+#endif
+        QWindowSystemInterface::registerTouchDevice(touchDevice);
+    }
 }
 
 QWindowsIntegrationPrivate::~QWindowsIntegrationPrivate()
@@ -496,13 +508,6 @@ QVariant QWindowsIntegration::styleHint(QPlatformIntegration::StyleHint hint) co
         break;
     case QPlatformIntegration::UseRtlExtensions:
         return QVariant(d->m_context.useRTLExtensions());
-    case QPlatformIntegration::SynthesizeMouseFromTouchEvents:
-#ifdef Q_OS_WINCE
-        // We do not want Qt to synthesize mouse events as Windows also does that.
-       return false;
-#else // Q_OS_WINCE
-       return QVariant(bool(d->m_options & DontPassOsMouseEventsSynthesizedFromTouch));
-#endif // !Q_OS_WINCE
     default:
         break;
     }

src/plugins/platforms/windows/qwindowsmousehandler.cpp

@@ -128,7 +128,10 @@ static inline QTouchDevice *createTouchDevice()
     QTouchDevice *result = new QTouchDevice;
     result->setType(digitizers & QT_NID_INTEGRATED_TOUCH
                     ? QTouchDevice::TouchScreen : QTouchDevice::TouchPad);
-    result->setCapabilities(QTouchDevice::Position | QTouchDevice::Area | QTouchDevice::NormalizedPosition);
+    QTouchDevice::Capabilities capabilities = QTouchDevice::Position | QTouchDevice::Area | QTouchDevice::NormalizedPosition;
+    if (result->type() == QTouchDevice::TouchPad)
+        capabilities |= QTouchDevice::MouseEmulation;
+    result->setCapabilities(capabilities);
     result->setMaximumTouchPoints(maxTouchPoints);
     return result;
 }
@@ -150,8 +153,6 @@ QWindowsMouseHandler::QWindowsMouseHandler() :
     m_leftButtonDown(false),
     m_previousCaptureWindow(0)
 {
-    if (m_touchDevice)
-        QWindowSystemInterface::registerTouchDevice(m_touchDevice);
 }
 
 Qt::MouseButtons QWindowsMouseHandler::queryMouseButtons()

src/plugins/platforms/winrt/qwinrttheme.cpp

@@ -224,8 +224,6 @@ QVariant QWinRTTheme::styleHint(QPlatformIntegration::StyleHint hint)
         return defaultThemeHint(StartDragVelocity);
     case QPlatformIntegration::UseRtlExtensions:
         return false;
-    case QPlatformIntegration::SynthesizeMouseFromTouchEvents:
-        return true;
     case QPlatformIntegration::PasswordMaskCharacter:
         return defaultThemeHint(PasswordMaskCharacter);
     case QPlatformIntegration::SetFocusOnTouchRelease:

src/plugins/platforms/xcb/qxcbconnection.cpp

@@ -299,7 +299,6 @@ QXcbConnection::QXcbConnection(QXcbNativeInterface *nativeInterface, bool canGra
     , has_shape_extension(false)
     , has_randr_extension(false)
     , has_input_shape(false)
-    , has_touch_without_mouse_emulation(false)
     , has_xkb(false)
     , m_buttons(0)
     , m_focusWindow(0)

src/plugins/platforms/xcb/qxcbconnection.h

@@ -442,7 +442,6 @@ public:
     bool hasXShape() const { return has_shape_extension; }
     bool hasXRandr() const { return has_randr_extension; }
     bool hasInputShape() const { return has_input_shape; }
-    bool hasTouchWithoutMouseEmulation() const { return has_touch_without_mouse_emulation; }
     bool hasXKB() const { return has_xkb; }
 
     bool supportsThreadedRendering() const { return m_reader->isRunning(); }
@@ -609,7 +608,6 @@ private:
     bool has_shape_extension;
     bool has_randr_extension;
     bool has_input_shape;
-    bool has_touch_without_mouse_emulation;
     bool has_xkb;
 
     Qt::MouseButtons m_buttons;

src/plugins/platforms/xcb/qxcbconnection_xi2.cpp

@@ -282,14 +282,14 @@ void QXcbConnection::xi2Select(xcb_window_t window)
         mask.mask_len = sizeof(bitMask);
         mask.mask = xiBitMask;
         if (!m_touchDevices.isEmpty()) {
-            mask.deviceid = XIAllMasterDevices;
-            Status result = XISelectEvents(xDisplay, window, &mask, 1);
             // If we select for touch events on the master pointer, XInput2
             // will not synthesize mouse events. This means Qt must do it,
             // which is also preferable, since Qt can control better when
             // to do so.
-            if (result == Success)
+            mask.deviceid = XIAllMasterDevices;
-                has_touch_without_mouse_emulation = true;
+            Status result = XISelectEvents(xDisplay, window, &mask, 1);
+            if (result != Success)
+                qCDebug(lcQpaXInput, "XInput 2.2: failed to select touch events, window %x, result %d", window, result);
         }
     }
 #endif // XCB_USE_XINPUT22
@@ -424,6 +424,9 @@ XInput2TouchDeviceData *QXcbConnection::touchDeviceForId(int id)
                     dev->size.width() > 10000 || dev->size.height() > 10000)
                 dev->size = QSizeF(130, 110);
         }
+        if (!isUsingXInput22() || type == QTouchDevice::TouchPad)
+            caps |= QTouchDevice::MouseEmulation;
+
         if (type >= QTouchDevice::TouchScreen && type <= QTouchDevice::TouchPad) {
             dev->qtTouchDevice = new QTouchDevice;
             dev->qtTouchDevice->setName(QString::fromUtf8(dev->xiDeviceInfo->name));

src/plugins/platforms/xcb/qxcbintegration.cpp

@@ -374,9 +374,6 @@ QVariant QXcbIntegration::styleHint(QPlatformIntegration::StyleHint hint) const
         // X11 always has support for windows, but the
         // window manager could prevent it (e.g. matchbox)
         return false;
-    case QPlatformIntegration::SynthesizeMouseFromTouchEvents:
-        // We do not want Qt to synthesize mouse events if X11 already does it.
-        return m_connections.at(0)->hasTouchWithoutMouseEmulation();
     default:
         break;
     }

tests/auto/gui/kernel/qwindow/tst_qwindow.cpp

@@ -68,6 +68,7 @@ private slots:
     void isActive();
     void testInputEvents();
     void touchToMouseTranslation();
+    void touchToMouseTranslationForDevices();
     void mouseToTouchTranslation();
     void mouseToTouchLoop();
     void touchCancel();
@@ -705,8 +706,6 @@ void tst_QWindow::testInputEvents()
 
 void tst_QWindow::touchToMouseTranslation()
 {
-    if (!QGuiApplicationPrivate::platformIntegration()->styleHint(QPlatformIntegration::SynthesizeMouseFromTouchEvents).toBool())
-        QSKIP("Mouse events are synthesized by the system on this platform.");
     InputTestWindow window;
     window.ignoreTouch = true;
     window.setGeometry(QRect(m_availableTopLeft + QPoint(80, 80), m_testWindowSize));
@@ -779,6 +778,35 @@ void tst_QWindow::touchToMouseTranslation()
     QTRY_COMPARE(window.mouseReleaseButton, 0);
 }
 
+void tst_QWindow::touchToMouseTranslationForDevices()
+{
+    InputTestWindow window;
+    window.ignoreTouch = true;
+    window.setGeometry(QRect(m_availableTopLeft + QPoint(80, 80), m_testWindowSize));
+    window.show();
+    QVERIFY(QTest::qWaitForWindowExposed(&window));
+
+    QPoint touchPoint(10, 10);
+
+    QTest::touchEvent(&window, touchDevice).press(0, touchPoint, &window);
+    QTest::touchEvent(&window, touchDevice).release(0, touchPoint, &window);
+    QCoreApplication::processEvents();
+
+    QCOMPARE(window.mousePressedCount, 1);
+    QCOMPARE(window.mouseReleasedCount, 1);
+
+    window.resetCounters();
+
+    touchDevice->setCapabilities(touchDevice->capabilities() | QTouchDevice::MouseEmulation);
+    QTest::touchEvent(&window, touchDevice).press(0, touchPoint, &window);
+    QTest::touchEvent(&window, touchDevice).release(0, touchPoint, &window);
+    QCoreApplication::processEvents();
+    touchDevice->setCapabilities(touchDevice->capabilities() & ~QTouchDevice::MouseEmulation);
+
+    QCOMPARE(window.mousePressedCount, 0);
+    QCOMPARE(window.mouseReleasedCount, 0);
+}
+
 void tst_QWindow::mouseToTouchTranslation()
 {
     qApp->setAttribute(Qt::AA_SynthesizeTouchForUnhandledMouseEvents, true);
@@ -907,8 +935,6 @@ void tst_QWindow::touchCancel()
 
 void tst_QWindow::touchCancelWithTouchToMouse()
 {
-    if (!QGuiApplicationPrivate::platformIntegration()->styleHint(QPlatformIntegration::SynthesizeMouseFromTouchEvents).toBool())
-        QSKIP("Mouse events are synthesized by the system on this platform.");
     InputTestWindow window;
     window.ignoreTouch = true;
     window.setGeometry(QRect(m_availableTopLeft + QPoint(80, 80), m_testWindowSize));

tests/auto/widgets/kernel/qapplication/tst_qapplication.cpp

@@ -2006,9 +2006,6 @@ void tst_QApplication::touchEventPropagation()
     int argc = 1;
     QApplication app(argc, &argv0);
 
-    const bool mouseEventSynthesizing = QGuiApplicationPrivate::platformIntegration()
-        ->styleHint(QPlatformIntegration::SynthesizeMouseFromTouchEvents).toBool();
-
     QList<QTouchEvent::TouchPoint> pressedTouchPoints;
     QTouchEvent::TouchPoint press(0);
     press.setState(Qt::TouchPointPressed);
@@ -2047,7 +2044,7 @@ void tst_QApplication::touchEventPropagation()
                                                  touchPointList(releasedTouchPoints));
         QCoreApplication::processEvents();
         QVERIFY(!window.seenTouchEvent);
-        QCOMPARE(window.seenMouseEvent, mouseEventSynthesizing); // QApplication may transform ignored touch events in mouse events
+        QVERIFY(window.seenMouseEvent); // QApplication may transform ignored touch events in mouse events
 
         window.reset();
         window.setAttribute(Qt::WA_AcceptTouchEvents);
@@ -2061,7 +2058,7 @@ void tst_QApplication::touchEventPropagation()
                                                  touchPointList(releasedTouchPoints));
         QCoreApplication::processEvents();
         QVERIFY(window.seenTouchEvent);
-        QCOMPARE(window.seenMouseEvent, mouseEventSynthesizing);
+        QVERIFY(window.seenMouseEvent);
 
         window.reset();
         window.acceptTouchEvent = true;
@@ -2100,9 +2097,9 @@ void tst_QApplication::touchEventPropagation()
                                                  touchPointList(releasedTouchPoints));
         QCoreApplication::processEvents();
         QVERIFY(!widget.seenTouchEvent);
-        QCOMPARE(widget.seenMouseEvent, mouseEventSynthesizing);
+        QVERIFY(widget.seenMouseEvent);
         QVERIFY(!window.seenTouchEvent);
-        QCOMPARE(window.seenMouseEvent, mouseEventSynthesizing);
+        QVERIFY(window.seenMouseEvent);
 
         window.reset();
         widget.reset();
@@ -2117,9 +2114,9 @@ void tst_QApplication::touchEventPropagation()
                                                  touchPointList(releasedTouchPoints));
         QCoreApplication::processEvents();
         QVERIFY(widget.seenTouchEvent);
-        QCOMPARE(widget.seenMouseEvent, mouseEventSynthesizing);
+        QVERIFY(widget.seenMouseEvent);
         QVERIFY(!window.seenTouchEvent);
-        QCOMPARE(window.seenMouseEvent, mouseEventSynthesizing);
+        QVERIFY(window.seenMouseEvent);
 
         window.reset();
         widget.reset();
@@ -2134,7 +2131,7 @@ void tst_QApplication::touchEventPropagation()
                                                  touchPointList(releasedTouchPoints));
         QCoreApplication::processEvents();
         QVERIFY(widget.seenTouchEvent);
-        QCOMPARE(widget.seenMouseEvent, mouseEventSynthesizing);
+        QVERIFY(widget.seenMouseEvent);
         QVERIFY(!window.seenTouchEvent);
         QVERIFY(!window.seenMouseEvent);
 
@@ -2169,9 +2166,9 @@ void tst_QApplication::touchEventPropagation()
                                                  touchPointList(releasedTouchPoints));
         QCoreApplication::processEvents();
         QVERIFY(!widget.seenTouchEvent);
-        QCOMPARE(widget.seenMouseEvent, mouseEventSynthesizing);
+        QVERIFY(widget.seenMouseEvent);
         QVERIFY(window.seenTouchEvent);
-        QCOMPARE(window.seenMouseEvent, mouseEventSynthesizing);
+        QVERIFY(window.seenMouseEvent);
 
         window.reset();
         widget.reset();
@@ -2186,13 +2183,13 @@ void tst_QApplication::touchEventPropagation()
                                                  touchPointList(releasedTouchPoints));
         QCoreApplication::processEvents();
         QVERIFY(!widget.seenTouchEvent);
-        QCOMPARE(widget.seenMouseEvent, mouseEventSynthesizing);
+        QVERIFY(!widget.seenMouseEvent);
         QVERIFY(window.seenTouchEvent);
         QVERIFY(!window.seenMouseEvent);
 
         window.reset();
         widget.reset();
-        widget.acceptMouseEvent = true; // it matters, touch events are propagated in parallel to synthesized mouse events
+        widget.acceptMouseEvent = true; // doesn't matter, touch events are propagated first
         window.acceptTouchEvent = true;
         QWindowSystemInterface::handleTouchEvent(window.windowHandle(),
                                                  0,
@@ -2204,8 +2201,8 @@ void tst_QApplication::touchEventPropagation()
                                                  touchPointList(releasedTouchPoints));
         QCoreApplication::processEvents();
         QVERIFY(!widget.seenTouchEvent);
-        QCOMPARE(widget.seenMouseEvent, mouseEventSynthesizing);
+        QVERIFY(!widget.seenMouseEvent);
-        QCOMPARE(!window.seenTouchEvent, mouseEventSynthesizing);
+        QVERIFY(window.seenTouchEvent);
         QVERIFY(!window.seenMouseEvent);
     }
 }

tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp

@@ -9824,9 +9824,6 @@ public:
 
 void tst_QWidget::touchEventSynthesizedMouseEvent()
 {
-    // Pass if the platform does not want mouse event synhesizing
-    if (!QGuiApplicationPrivate::platformIntegration()->styleHint(QPlatformIntegration::SynthesizeMouseFromTouchEvents).toBool())
-        return;
     if (m_platform == QStringLiteral("wayland"))
         QSKIP("Wayland: This fails. Figure out why.");
 
@@ -9852,7 +9849,7 @@ void tst_QWidget::touchEventSynthesizedMouseEvent()
         QCOMPARE(widget.m_lastMouseEventPos, QPointF(15, 15));
         QTest::touchEvent(&widget, device).release(0, QPoint(20, 20), &widget);
         QCOMPARE(widget.m_touchEventCount, 0);
-        QCOMPARE(widget.m_mouseEventCount, 3);
+        QCOMPARE(widget.m_mouseEventCount, 4); // we receive extra mouse move event
         QCOMPARE(widget.m_lastMouseEventPos, QPointF(20, 20));
     }
 
@@ -9903,8 +9900,7 @@ void tst_QWidget::touchEventSynthesizedMouseEvent()
         QCOMPARE(parent.m_touchEventCount, 1);
         QCOMPARE(parent.m_mouseEventCount, 0);
         QCOMPARE(child.m_touchEventCount, 0);
-        QCOMPARE(child.m_mouseEventCount, 1); // Attempt at mouse event before propagation
+        QCOMPARE(child.m_mouseEventCount, 0);
-        QCOMPARE(child.m_lastMouseEventPos, QPointF(10, 10));
     }
 
     {