WinTab: Switch stylus pointer type when the tablet is in the tablet proximity

Some convertible tablet devices have a special stylus button that
converts the stylus into an eraser. Such button can be pressed right
when the stylus is in tablet surface proximity, so we should check
that not only during proximity event handling, but also while parsing
normal wintab packets.

Make sure that we don't switch tablet pointer type while any **mapped**
stylus button is pressed. Pressing the "eraser" button is reported
in pkButtons, but it maps to none by CSR_SYSBTNMAP

https://bugs.kde.org/show_bug.cgi?id=405747
https://bugs.kde.org/show_bug.cgi?id=408454

Pick-to: 5.15
Change-Id: I1d254f0cf79be6ceb194b1c4b314a11831f50170
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

1 files changed, 21 insertions, 4 deletions

diff --git a/src/plugins/platforms/windows/qwindowstabletsupport.cpp b/src/plugins/platforms/windows/qwindowstabletsupport.cpp
index 9c831036d9..f16015b96a 100644
--- a/src/plugins/platforms/windows/qwindowstabletsupport.cpp
+++ b/src/plugins/platforms/windows/qwindowstabletsupport.cpp
@@ -529,7 +529,6 @@ bool QWindowsTabletSupport::translateTabletPacketEvent()
         return false;
 
     const auto currentDevice = m_devices.at(m_currentDevice).currentDevice;
-    const auto currentPointer = m_devices.at(m_currentDevice).currentPointerType;
     const qint64 uniqueId = m_devices.at(m_currentDevice).uniqueId;
 
     // The tablet can be used in 2 different modes (reflected in enum Mode),
@@ -561,6 +560,27 @@ bool QWindowsTabletSupport::translateTabletPacketEvent()
 
         const int z = m_devices.at(m_currentDevice).zCapability ? int(packet.pkZ) : 0;
 
+        const auto currentPointer = m_devices.at(m_currentDevice).currentPointerType;
+        const auto packetPointerType = pointerType(packet.pkCursor);
+
+        const Qt::MouseButtons buttons =
+            convertTabletButtons(packet.pkButtons, m_devices.at(m_currentDevice));
+
+        if (buttons == Qt::NoButton && packetPointerType != currentPointer) {
+
+            QWindowSystemInterface::handleTabletLeaveProximityEvent(packet.pkTime,
+                                                                    int(currentDevice),
+                                                                    int(currentPointer),
+                                                                    uniqueId);
+
+            m_devices[m_currentDevice].currentPointerType = packetPointerType;
+
+            QWindowSystemInterface::handleTabletEnterProximityEvent(packet.pkTime,
+                                                                    int(currentDevice),
+                                                                    int(packetPointerType),
+                                                                    uniqueId);
+        }
+
         QPointF globalPosF =
             m_devices.at(m_currentDevice).scaleCoordinates(packet.pkX, packet.pkY, virtualDesktopArea);
 
@@ -627,9 +647,6 @@ bool QWindowsTabletSupport::translateTabletPacketEvent()
                 << tiltY << "tanP:" << tangentialPressure << "rotation:" << rotation;
         }
 
-        Qt::MouseButtons buttons =
-            convertTabletButtons(packet.pkButtons, m_devices.at(m_currentDevice));
-
         QWindowSystemInterface::handleTabletEvent(target, packet.pkTime, QPointF(localPos), globalPosF,
                                                   int(currentDevice), int(currentPointer),
                                                   buttons,