diff --git a/src/backends/x11/windowed/x11_windowed_backend.cpp b/src/backends/x11/windowed/x11_windowed_backend.cpp
index e175a04a7c..190a1a6891 100644
--- a/src/backends/x11/windowed/x11_windowed_backend.cpp
+++ b/src/backends/x11/windowed/x11_windowed_backend.cpp
@@ -603,6 +603,36 @@ xcb_window_t X11WindowedBackend::windowForScreen(Output *output) const
     return static_cast<X11WindowedOutput *>(output)->window();
 }
 
+xcb_connection_t *X11WindowedBackend::connection() const
+{
+    return m_connection;
+}
+
+xcb_screen_t *X11WindowedBackend::screen() const
+{
+    return m_screen;
+}
+
+int X11WindowedBackend::screenNumer() const
+{
+    return m_screenNumber;
+}
+
+Display *X11WindowedBackend::display() const
+{
+    return m_display;
+}
+
+bool X11WindowedBackend::hasXInput() const
+{
+    return m_hasXInput;
+}
+
+QVector<CompositingType> X11WindowedBackend::supportedCompositors() const
+{
+    return QVector<CompositingType>{OpenGLCompositing, QPainterCompositing};
+}
+
 xcb_window_t X11WindowedBackend::window() const
 {
     return m_outputs.first()->window();
diff --git a/src/backends/x11/windowed/x11_windowed_backend.h b/src/backends/x11/windowed/x11_windowed_backend.h
index 7758be1d04..7667024df0 100644
--- a/src/backends/x11/windowed/x11_windowed_backend.h
+++ b/src/backends/x11/windowed/x11_windowed_backend.h
@@ -96,47 +96,28 @@ class KWIN_EXPORT X11WindowedBackend : public OutputBackend
 public:
     explicit X11WindowedBackend(const X11WindowedBackendOptions &options);
     ~X11WindowedBackend() override;
-    bool initialize() override;
 
-    xcb_connection_t *connection() const
-    {
-        return m_connection;
-    }
-    xcb_screen_t *screen() const
-    {
-        return m_screen;
-    }
-    int screenNumer() const
-    {
-        return m_screenNumber;
-    }
+    Display *display() const;
+    xcb_connection_t *connection() const;
+    xcb_screen_t *screen() const;
+    int screenNumer() const;
+    xcb_window_t rootWindow() const;
+
     xcb_window_t window() const;
     xcb_window_t windowForScreen(Output *output) const;
-    Display *display() const
-    {
-        return m_display;
-    }
-    xcb_window_t rootWindow() const;
-    bool hasXInput() const
-    {
-        return m_hasXInput;
-    }
+    bool hasXInput() const;
 
+    bool initialize() override;
     std::unique_ptr<OpenGLBackend> createOpenGLBackend() override;
     std::unique_ptr<QPainterBackend> createQPainterBackend() override;
     std::unique_ptr<InputBackend> createInputBackend() override;
-
-    QVector<CompositingType> supportedCompositors() const override
-    {
-        return QVector<CompositingType>{OpenGLCompositing, QPainterCompositing};
-    }
+    QVector<CompositingType> supportedCompositors() const override;
+    Outputs outputs() const override;
 
     X11WindowedInputDevice *pointerDevice() const;
     X11WindowedInputDevice *keyboardDevice() const;
     X11WindowedInputDevice *touchDevice() const;
 
-    Outputs outputs() const override;
-
 private:
     void createOutputs();
     void grabKeyboard(xcb_timestamp_t time);
diff --git a/src/backends/x11/windowed/x11_windowed_output.cpp b/src/backends/x11/windowed/x11_windowed_output.cpp
index c16d8cfee2..d0568e7e02 100644
--- a/src/backends/x11/windowed/x11_windowed_output.cpp
+++ b/src/backends/x11/windowed/x11_windowed_output.cpp
@@ -136,6 +136,26 @@ SoftwareVsyncMonitor *X11WindowedOutput::vsyncMonitor() const
     return m_vsyncMonitor.get();
 }
 
+X11WindowedBackend *X11WindowedOutput::backend() const
+{
+    return m_backend;
+}
+
+X11WindowedCursor *X11WindowedOutput::cursor() const
+{
+    return m_cursor.get();
+}
+
+xcb_window_t X11WindowedOutput::window() const
+{
+    return m_window;
+}
+
+QPoint X11WindowedOutput::hostPosition() const
+{
+    return m_hostPosition;
+}
+
 void X11WindowedOutput::init(const QSize &pixelSize, qreal scale)
 {
     const int refreshRate = 60000; // TODO: get refresh rate via randr
diff --git a/src/backends/x11/windowed/x11_windowed_output.h b/src/backends/x11/windowed/x11_windowed_output.h
index 5dbe35c2a8..64ba861d20 100644
--- a/src/backends/x11/windowed/x11_windowed_output.h
+++ b/src/backends/x11/windowed/x11_windowed_output.h
@@ -57,24 +57,12 @@ public:
     void init(const QSize &pixelSize, qreal scale);
     void resize(const QSize &pixelSize);
 
-    X11WindowedBackend *backend() const
-    {
-        return m_backend;
-    }
-    X11WindowedCursor *cursor() const
-    {
-        return m_cursor.get();
-    }
-    xcb_window_t window() const
-    {
-        return m_window;
-    }
+    X11WindowedBackend *backend() const;
+    X11WindowedCursor *cursor() const;
+    xcb_window_t window() const;
 
     QPoint internalPosition() const;
-    QPoint hostPosition() const
-    {
-        return m_hostPosition;
-    }
+    QPoint hostPosition() const;
     void setHostPosition(const QPoint &pos);
 
     void setWindowTitle(const QString &title);