Lay some groundwork for realtime gestures in Wayland

This lays down some groundwork for realtime gestures in Wayland,
so that gestures that are 1:1 with user motion on a touchpad are
now possible to implement.

Due to earlier commits, this is mostly just glue code to make a
convenient API.

Gestures implemented with this API are four-finger gestures, to
avoid conflicting with apps that may use two or three-finger
gestures.

autotests/mock_effectshandler.h

@@ -174,6 +174,7 @@ public:
     void registerGlobalShortcut(const QKeySequence &, QAction *) override {}
     void registerPointerShortcut(Qt::KeyboardModifiers, Qt::MouseButton, QAction *) override {}
     void registerTouchpadSwipeShortcut(KWin::SwipeDirection, QAction *) override {}
+    void registerRealtimeTouchpadSwipeShortcut(KWin::SwipeDirection, QAction*, std::function<void(qreal)>) override {}
     void reloadEffect(KWin::Effect *) override {}
     void removeSupportProperty(const QByteArray &, KWin::Effect *) override {}
     void reserveElectricBorder(KWin::ElectricBorder, KWin::Effect *) override {}

src/effects.cpp

@@ -750,6 +750,11 @@ void EffectsHandlerImpl::registerAxisShortcut(Qt::KeyboardModifiers modifiers, P
     input()->registerAxisShortcut(modifiers, axis, action);
 }
 
+void EffectsHandlerImpl::registerRealtimeTouchpadSwipeShortcut(SwipeDirection dir, QAction* onUp, std::function<void(qreal)> progressCallback)
+{
+    input()->registerRealtimeTouchpadSwipeShortcut(dir, onUp, progressCallback);
+}
+
 void EffectsHandlerImpl::registerTouchpadSwipeShortcut(SwipeDirection direction, QAction *action)
 {
     input()->registerTouchpadSwipeShortcut(direction, action);

src/effects.h

@@ -110,6 +110,7 @@ public:
     void registerGlobalShortcut(const QKeySequence &shortcut, QAction *action) override;
     void registerPointerShortcut(Qt::KeyboardModifiers modifiers, Qt::MouseButton pointerButtons, QAction *action) override;
     void registerAxisShortcut(Qt::KeyboardModifiers modifiers, PointerAxisDirection axis, QAction *action) override;
+    void registerRealtimeTouchpadSwipeShortcut(SwipeDirection dir, QAction* onUp, std::function<void(qreal)> progressCallback) override;
     void registerTouchpadSwipeShortcut(SwipeDirection direction, QAction *action) override;
     void* getProxy(QString name) override;
     void startMousePolling() override;

src/globalshortcuts.cpp

@@ -20,6 +20,7 @@
 // Qt
 #include <QAction>
 #include <variant>
+#include <signal.h>
 
 namespace KWin
 {
@@ -39,6 +40,17 @@ GlobalShortcut::GlobalShortcut(Shortcut &&sc, QAction *action)
         m_gesture->setMaximumFingerCount(4);
         m_gesture->setMinimumFingerCount(4);
         QObject::connect(m_gesture.get(), &SwipeGesture::triggered, m_action, &QAction::trigger, Qt::QueuedConnection);
+    } else if (auto rtSwipeGesture = std::get_if<FourFingerRealtimeFeedbackSwipeShortcut>(&sc)) {
+        m_gesture.reset(new SwipeGesture);
+        m_gesture->setDirection(dirs[rtSwipeGesture->swipeDirection]);
+        m_gesture->setMinimumDelta(QSizeF(200, 200));
+        m_gesture->setMaximumFingerCount(4);
+        m_gesture->setMinimumFingerCount(4);
+        QObject::connect(m_gesture.get(), &SwipeGesture::triggered, m_action, &QAction::trigger, Qt::QueuedConnection);
+        QObject::connect(m_gesture.get(), &SwipeGesture::cancelled, m_action, &QAction::trigger, Qt::QueuedConnection);
+        QObject::connect(m_gesture.get(), &SwipeGesture::progress, [cb = rtSwipeGesture->progressCallback](qreal v) {
+            cb(v);
+        });
     }
 }
 
@@ -111,7 +123,7 @@ bool GlobalShortcutsManager::addIfNotExists(GlobalShortcut sc)
         }
     }
 
-    if (std::holds_alternative<FourFingerSwipeShortcut>(sc.shortcut())) {
+    if (std::holds_alternative<FourFingerSwipeShortcut>(sc.shortcut()) || std::holds_alternative<FourFingerRealtimeFeedbackSwipeShortcut>(sc.shortcut())) {
         m_gestureRecognizer->registerGesture(sc.swipeGesture());
     }
     connect(sc.action(), &QAction::destroyed, this, &GlobalShortcutsManager::objectDeleted);
@@ -134,6 +146,11 @@ void GlobalShortcutsManager::registerTouchpadSwipe(QAction *action, SwipeDirecti
     addIfNotExists(GlobalShortcut(FourFingerSwipeShortcut{direction}, action));
 }
 
+void GlobalShortcutsManager::registerRealtimeTouchpadSwipe(QAction *action, std::function<void (qreal)> progressCallback, SwipeDirection direction)
+{
+    addIfNotExists(GlobalShortcut(FourFingerRealtimeFeedbackSwipeShortcut{direction, progressCallback}, action));
+}
+
 bool GlobalShortcutsManager::processKey(Qt::KeyboardModifiers mods, int keyQt)
 {
     if (m_kglobalAccelInterface) {

src/globalshortcuts.h

@@ -60,6 +60,8 @@ public:
 
     void registerTouchpadSwipe(QAction *action, SwipeDirection direction);
 
+    void registerRealtimeTouchpadSwipe(QAction *onUp, std::function<void(qreal)> progressCallback, SwipeDirection direction);
+
     /**
      * @brief Processes a key event to decide whether a shortcut needs to be triggered.
      *
@@ -141,8 +143,19 @@ struct FourFingerSwipeShortcut
         return swipeDirection == rhs.swipeDirection;
     }
 };
+struct FourFingerRealtimeFeedbackSwipeShortcut
+{
+    SwipeDirection swipeDirection;
+    std::function<void(qreal)> progressCallback;
 
-using Shortcut = std::variant<KeyboardShortcut, PointerButtonShortcut, PointerAxisShortcut, FourFingerSwipeShortcut>;
+    template<typename T>
+    bool operator==(const T& rhs) const
+    {
+        return swipeDirection == rhs.swipeDirection;
+    }
+};
+
+using Shortcut = std::variant<KeyboardShortcut, PointerButtonShortcut, PointerAxisShortcut, FourFingerSwipeShortcut, FourFingerRealtimeFeedbackSwipeShortcut>;
 
 class GlobalShortcut
 {

src/input.cpp

@@ -2701,6 +2701,11 @@ void InputRedirection::registerAxisShortcut(Qt::KeyboardModifiers modifiers, Poi
     m_shortcuts->registerAxisShortcut(action, modifiers, axis);
 }
 
+void InputRedirection::registerRealtimeTouchpadSwipeShortcut(SwipeDirection direction, QAction *action, std::function<void(qreal)> cb)
+{
+    m_shortcuts->registerRealtimeTouchpadSwipe(action, cb, direction);
+}
+
 void InputRedirection::registerTouchpadSwipeShortcut(SwipeDirection direction, QAction *action)
 {
     m_shortcuts->registerTouchpadSwipe(action, direction);

src/input.h

@@ -139,6 +139,7 @@ public:
     void registerPointerShortcut(Qt::KeyboardModifiers modifiers, Qt::MouseButton pointerButtons, QAction *action);
     void registerAxisShortcut(Qt::KeyboardModifiers modifiers, PointerAxisDirection axis, QAction *action);
     void registerTouchpadSwipeShortcut(SwipeDirection direction, QAction *action);
+    void registerRealtimeTouchpadSwipeShortcut(SwipeDirection direction, QAction *onUp, std::function<void(qreal)> progressCallback);
     void registerGlobalAccel(KGlobalAccelInterface *interface);
 
     /**

src/libkwineffects/kwineffects.h

@@ -886,6 +886,8 @@ public:
      */
     virtual void registerTouchpadSwipeShortcut(SwipeDirection direction, QAction *action) = 0;
 
+    virtual void registerRealtimeTouchpadSwipeShortcut(SwipeDirection dir, QAction* onUp, std::function<void(qreal)> progressCallback) = 0;
+
     /**
      * Retrieve the proxy class for an effect if it has one. Will return NULL if
      * the effect isn't loaded or doesn't have a proxy class.