Specify inputTransformation in Toplevel

InputRedirection uses the inputTransformation() to pass to SeatInterface
for focused pointer surface. This prepares for proper input
transformation including scaling and rotation.

input.cpp

@@ -538,7 +538,7 @@ void InputRedirection::updatePointerWindow()
             }
         }
         if (t && t->surface()) {
-            seat->setFocusedPointerSurface(t->surface(), t->pos());
+            seat->setFocusedPointerSurface(t->surface(), t->inputTransformation());
             connect(t, &Toplevel::geometryChanged, this, &InputRedirection::updateFocusedPointerPosition);
             if (AbstractBackend *b = waylandServer()->backend()) {
                 b->installCursorFromServer();
@@ -679,7 +679,7 @@ void InputRedirection::updateFocusedPointerPosition()
         if (m_pointerWindow.data()->surface() != seat->focusedPointerSurface()) {
             return;
         }
-        seat->setFocusedPointerSurfacePosition(m_pointerWindow.data()->pos());
+        seat->setFocusedPointerSurfaceTransformation(m_pointerWindow.data()->inputTransformation());
     }
 }
 
@@ -710,7 +710,7 @@ void InputRedirection::processPointerMotion(const QPointF &pos, uint32_t time)
         Toplevel *t = findToplevel(m_globalPointer.toPoint());
         if (t && t->surface()) {
             if (auto seat = findSeat()) {
-                seat->setFocusedPointerSurface(t->surface(), t->pos());
+                seat->setFocusedPointerSurface(t->surface(), t->inputTransformation());
                 seat->setTimestamp(time);
                 seat->setPointerPos(m_globalPointer);
             }

toplevel.cpp

@@ -517,6 +517,13 @@ void Toplevel::setInternalFramebufferObject(const QSharedPointer<QOpenGLFramebuf
     setDepth(32);
 }
 
+QMatrix4x4 Toplevel::inputTransformation() const
+{
+    QMatrix4x4 m;
+    m.translate(-x(), -y());
+    return m;
+}
+
 } // namespace
 
 #include "toplevel.moc"

toplevel.h

@@ -30,6 +30,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <NETWM>
 // Qt
 #include <QObject>
+#include <QMatrix4x4>
 // xcb
 #include <xcb/damage.h>
 #include <xcb/xfixes.h>
@@ -371,6 +372,14 @@ public:
     virtual void setInternalFramebufferObject(const QSharedPointer<QOpenGLFramebufferObject> &fbo);
     const QSharedPointer<QOpenGLFramebufferObject> &internalFramebufferObject() const;
 
+    /**
+     * @returns Transformation to map from global to window coordinates.
+     *
+     * Default implementation returns a translation on negative pos().
+     * @see pos
+     **/
+    virtual QMatrix4x4 inputTransformation() const;
+
     /**
      * @brief Finds the Toplevel matching the condition expressed in @p func in @p list.
      *