Introduce SurfaceCursorSource

The contents of the cursor can be either a normal image or a wl_surface.
At the moment, we get an image from the wl_surface. But it's going to be
changed so we use SurfaceItem to render wl_surface cursors.

SurfaceCursorSource provides the way to get the wl_surface handle from
the cursor. In order to provide backwards compatibility, it also provides
a QImage.

src/cursorsource.cpp

@@ -6,6 +6,8 @@
 
 #include "cursorsource.h"
 #include "cursor.h"
+#include "wayland/shmclientbuffer.h"
+#include "wayland/surface_interface.h"
 
 namespace KWin
 {
@@ -116,4 +118,34 @@ void ShapeCursorSource::selectSprite(int index)
     Q_EMIT changed();
 }
 
+SurfaceCursorSource::SurfaceCursorSource(QObject *parent)
+    : CursorSource(parent)
+{
+}
+
+KWaylandServer::SurfaceInterface *SurfaceCursorSource::surface() const
+{
+    return m_surface;
+}
+
+void SurfaceCursorSource::update(KWaylandServer::SurfaceInterface *surface, const QPoint &hotspot)
+{
+    if (!surface) {
+        m_image = QImage();
+        m_hotspot = QPoint();
+        m_surface = nullptr;
+    } else {
+        auto buffer = qobject_cast<KWaylandServer::ShmClientBuffer *>(surface->buffer());
+        if (buffer) {
+            m_image = buffer->data().copy();
+            m_image.setDevicePixelRatio(surface->bufferScale());
+        } else {
+            m_image = QImage();
+        }
+        m_hotspot = hotspot;
+        m_surface = surface;
+    }
+    Q_EMIT changed();
+}
+
 } // namespace KWin

src/cursorsource.h

@@ -11,8 +11,14 @@
 #include <QImage>
 #include <QObject>
 #include <QPoint>
+#include <QPointer>
 #include <QTimer>
 
+namespace KWaylandServer
+{
+class SurfaceInterface;
+}
+
 namespace KWin
 {
 
@@ -80,4 +86,23 @@ private:
     int m_currentSprite = -1;
 };
 
+/**
+ * The SurfaceCursorSource class repsents the contents of a cursor backed by a wl_surface.
+ */
+class KWIN_EXPORT SurfaceCursorSource : public CursorSource
+{
+    Q_OBJECT
+
+public:
+    explicit SurfaceCursorSource(QObject *parent = nullptr);
+
+    KWaylandServer::SurfaceInterface *surface() const;
+
+public Q_SLOTS:
+    void update(KWaylandServer::SurfaceInterface *surface, const QPoint &hotspot);
+
+private:
+    QPointer<KWaylandServer::SurfaceInterface> m_surface;
+};
+
 } // namespace KWin

src/pointer_input.cpp

@@ -20,12 +20,10 @@
 #include "input_event_spy.h"
 #include "mousebuttons.h"
 #include "osd.h"
-#include "wayland/datadevice_interface.h"
 #include "wayland/display.h"
 #include "wayland/pointer_interface.h"
 #include "wayland/pointerconstraints_v1_interface.h"
 #include "wayland/seat_interface.h"
-#include "wayland/shmclientbuffer.h"
 #include "wayland/surface_interface.h"
 #include "wayland_server.h"
 #include "workspace.h"
@@ -891,7 +889,7 @@ CursorImage::CursorImage(PointerInputRedirection *parent)
     m_moveResizeCursor = std::make_unique<ShapeCursorSource>();
     m_windowSelectionCursor = std::make_unique<ShapeCursorSource>();
     m_decoration.cursor = std::make_unique<ShapeCursorSource>();
-    m_serverCursor.cursor = std::make_unique<ImageCursorSource>();
+    m_serverCursor.cursor = std::make_unique<SurfaceCursorSource>();
 
     connect(waylandServer()->seat(), &KWaylandServer::SeatInterface::hasPointerChanged,
             this, &CursorImage::handlePointerChanged);
@@ -1014,23 +1012,9 @@ void CursorImage::updateServerCursor()
         return;
     }
     auto c = p->cursor();
-    if (!c) {
-        return;
+    if (c) {
+        m_serverCursor.cursor->update(c->surface(), c->hotspot());
     }
-
-    QImage image;
-    QPoint hotspot;
-
-    if (c->surface()) {
-        auto buffer = qobject_cast<KWaylandServer::ShmClientBuffer *>(c->surface()->buffer());
-        if (buffer) {
-            image = buffer->data().copy();
-            image.setDevicePixelRatio(c->surface()->bufferScale());
-            hotspot = c->hotspot();
-        }
-    }
-
-    m_serverCursor.cursor->update(image, hotspot);
 }
 
 void CursorImage::setEffectsOverrideCursor(Qt::CursorShape shape)

src/pointer_input.h

@@ -35,6 +35,7 @@ class InputRedirection;
 class CursorShape;
 class ImageCursorSource;
 class ShapeCursorSource;
+class SurfaceCursorSource;
 
 namespace Decoration
 {
@@ -245,7 +246,7 @@ private:
     struct
     {
         QMetaObject::Connection connection;
-        std::unique_ptr<ImageCursorSource> cursor;
+        std::unique_ptr<SurfaceCursorSource> cursor;
     } m_serverCursor;
 };