ButtonRebindsFilter: Set cursor position when rebinding tablet events

Since the tablet cursor and the mouse cursor is tracked separately,
rebinding a tablet button to a mouse click is sort of wonky. For
example, if you assign it to Right Click and attempt to open a context
menu it will appear to open in the wrong place.

So before we send the mouse button event, set the mouse position to
the tablet cursor position. A test is added to ensure this functionality
works as intended and doesn't regress.

autotests/integration/buttonrebind_test.cpp

@@ -9,6 +9,7 @@
 #include "kwin_wayland_test.h"
 
 #include "pointer_input.h"
+#include "tablet_input.h"
 #include "wayland_server.h"
 #include "workspace.h"
 
@@ -42,6 +43,8 @@ private Q_SLOTS:
     void testBindingTabletPad();
     void testBindingTabletTool();
 
+    void testMouseTabletCursorSync();
+
 private:
     quint32 timestamp = 1;
 };
@@ -238,5 +241,44 @@ void TestButtonRebind::testBindingTabletTool()
     Test::tabletToolButtonReleased(BTN_STYLUS, timestamp++);
 }
 
+void TestButtonRebind::testMouseTabletCursorSync()
+{
+    KConfigGroup buttonGroup = KSharedConfig::openConfig(QStringLiteral("kcminputrc"))->group(QStringLiteral("ButtonRebinds")).group(QStringLiteral("TabletTool")).group(QStringLiteral("Virtual Tablet Tool 1"));
+    buttonGroup.writeEntry(QString::number(BTN_STYLUS), QStringList{"MouseButton", QString::number(BTN_LEFT)}, KConfig::Notify);
+    buttonGroup.sync();
+
+    std::unique_ptr<KWayland::Client::Surface> surface = Test::createSurface();
+    std::unique_ptr<Test::XdgToplevel> shellSurface = Test::createXdgToplevelSurface(surface.get());
+    auto window = Test::renderAndWaitForShown(surface.get(), QSize(100, 50), Qt::blue);
+
+    std::unique_ptr<KWayland::Client::Pointer> pointer(Test::waylandSeat()->createPointer());
+    QSignalSpy enteredSpy(pointer.get(), &KWayland::Client::Pointer::entered);
+    QSignalSpy buttonChangedSpy(pointer.get(), &KWayland::Client::Pointer::buttonStateChanged);
+
+    const QRectF startGeometry = window->frameGeometry();
+
+    // Move the mouse cursor to (25, 25)
+    input()->pointer()->warp(startGeometry.topLeft() + QPointF{25.f, 25.5f});
+    QVERIFY(enteredSpy.wait());
+
+    // Move the tablet cursor to (10,10)
+    Test::tabletToolEvent(InputRedirection::Proximity, startGeometry.topLeft() + QPointF{10.f, 10.f}, 1.0, 0, 0, 0, false, false, timestamp++);
+
+    // Verify they are not starting in the same place
+    QVERIFY(input()->pointer()->pos() != input()->tablet()->position());
+
+    // Send the tablet button event so it can be processed by the filter
+    Test::tabletToolButtonPressed(BTN_STYLUS, timestamp++);
+
+    QVERIFY(buttonChangedSpy.wait());
+    QCOMPARE(buttonChangedSpy.count(), 1);
+    QCOMPARE(buttonChangedSpy.at(0).at(2).value<qint32>(), BTN_LEFT);
+
+    Test::tabletToolButtonReleased(BTN_STYLUS, timestamp++);
+
+    // Verify that by using the mouse button binding, the mouse cursor was moved to the tablet cursor position
+    QVERIFY(input()->pointer()->pos() == input()->tablet()->position());
+}
+
 WAYLANDTEST_MAIN(TestButtonRebind)
 #include "buttonrebind_test.moc"

src/plugins/buttonrebinds/buttonrebindsfilter.cpp

@@ -205,6 +205,15 @@ bool ButtonRebindsFilter::pointerEvent(KWin::MouseEvent *event, quint32 nativeBu
     return send(Pointer, {{}, event->button()}, event->type() == QEvent::MouseButtonPress, event->timestamp());
 }
 
+bool ButtonRebindsFilter::tabletToolEvent(KWin::TabletEvent *event)
+{
+    if (RebindScope::isRebinding()) {
+        return false;
+    }
+    m_tabletCursorPos = event->position();
+    return false;
+}
+
 bool ButtonRebindsFilter::tabletPadButtonEvent(uint button, bool pressed, const KWin::TabletPadId &tabletPadId, std::chrono::microseconds time)
 {
     if (RebindScope::isRebinding()) {
@@ -282,6 +291,9 @@ bool ButtonRebindsFilter::send(TriggerType type, const Trigger &trigger, bool pr
         return sendKeySequence(*seq, pressed, timestamp);
     }
     if (const auto mb = std::get_if<MouseButton>(&action)) {
+        if (pressed && type != Pointer) {
+            sendMousePosition(m_tabletCursorPos, timestamp);
+        }
         return sendMouseButton(mb->button, pressed, timestamp);
     }
     if (const auto tb = std::get_if<TabletToolButton>(&action)) {
@@ -379,6 +391,13 @@ bool ButtonRebindsFilter::sendMouseButton(quint32 button, bool pressed, std::chr
     return true;
 }
 
+bool ButtonRebindsFilter::sendMousePosition(QPointF position, std::chrono::microseconds time)
+{
+    RebindScope scope;
+    Q_EMIT m_inputDevice.pointerMotionAbsolute(position, time, &m_inputDevice);
+    return true;
+}
+
 bool ButtonRebindsFilter::sendTabletToolButton(quint32 button, bool pressed, std::chrono::microseconds time)
 {
     if (!m_tabletTool) {

src/plugins/buttonrebinds/buttonrebindsfilter.h

@@ -74,6 +74,7 @@ public:
 
     explicit ButtonRebindsFilter();
     bool pointerEvent(KWin::MouseEvent *event, quint32 nativeButton) override;
+    bool tabletToolEvent(KWin::TabletEvent *event) override;
     bool tabletPadButtonEvent(uint button, bool pressed, const KWin::TabletPadId &tabletPadId, std::chrono::microseconds time) override;
     bool tabletToolButtonEvent(uint button, bool pressed, const KWin::TabletToolId &tabletToolId, std::chrono::microseconds time) override;
 
@@ -83,10 +84,12 @@ private:
     bool send(TriggerType type, const Trigger &trigger, bool pressed, std::chrono::microseconds timestamp);
     bool sendKeySequence(const QKeySequence &sequence, bool pressed, std::chrono::microseconds time);
     bool sendMouseButton(quint32 button, bool pressed, std::chrono::microseconds time);
+    bool sendMousePosition(QPointF position, std::chrono::microseconds time);
     bool sendTabletToolButton(quint32 button, bool pressed, std::chrono::microseconds time);
 
     InputDevice m_inputDevice;
     std::array<QHash<Trigger, std::variant<QKeySequence, MouseButton, TabletToolButton, DisabledButton>>, LastType> m_actions;
     KConfigWatcher::Ptr m_configWatcher;
     std::optional<KWin::TabletToolId> m_tabletTool;
+    QPointF m_cursorPos, m_tabletCursorPos;
 };