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>

4 files changed, 7 insertions, 10 deletions

diff --git a/src/plugins/platforms/xcb/qxcbconnection.cpp b/src/plugins/platforms/xcb/qxcbconnection.cpp
index 43c73671a9..d5cf708ed2 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.cpp
+++ b/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)
diff --git a/src/plugins/platforms/xcb/qxcbconnection.h b/src/plugins/platforms/xcb/qxcbconnection.h
index 391d4c10cc..a3c8c0b95e 100644
--- a/src/plugins/platforms/xcb/qxcbconnection.h
+++ b/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;
diff --git a/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp b/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp
index e9fb47dabd..d1b3ead11c 100644
--- a/src/plugins/platforms/xcb/qxcbconnection_xi2.cpp
+++ b/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)
-                has_touch_without_mouse_emulation = true;
+            mask.deviceid = XIAllMasterDevices;
+            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));
diff --git a/src/plugins/platforms/xcb/qxcbintegration.cpp b/src/plugins/platforms/xcb/qxcbintegration.cpp
index 1676035f6b..258359d20f 100644
--- a/src/plugins/platforms/xcb/qxcbintegration.cpp
+++ b/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;
     }