diff --git a/x11client.h b/x11client.h
--- a/x11client.h
+++ b/x11client.h
@@ -89,6 +89,7 @@
     xcb_window_t inputId() const { return m_decoInputExtent; }
     xcb_window_t frameId() const override;
 
+    QRect inputGeometry() const override;
     QRect bufferGeometry() const override;
     QMargins bufferMargins() const override;
 
@@ -98,6 +99,8 @@
     QSize clientSizeToFrameSize(const QSize &size) const override;
     QRect frameRectToBufferRect(const QRect &rect) const;
 
+    QMatrix4x4 inputTransformation() const override;
+
     bool isTransient() const override;
     bool groupTransient() const override;
     bool wasOriginallyGroupTransient() const;
diff --git a/x11client.cpp b/x11client.cpp
--- a/x11client.cpp
+++ b/x11client.cpp
@@ -2634,6 +2634,15 @@
     return m_frame;
 }
 
+QRect X11Client::inputGeometry() const
+{
+    // Remember that the buffer geometry corresponds to the geometry of the frame window.
+    if (isDecorated()) {
+        return m_bufferGeometry + decoration()->resizeOnlyBorders();
+    }
+    return m_bufferGeometry;
+}
+
 QRect X11Client::bufferGeometry() const
 {
     return m_bufferGeometry;
@@ -2716,6 +2725,13 @@
     return frameRectToClientRect(rect);
 }
 
+QMatrix4x4 X11Client::inputTransformation() const
+{
+    QMatrix4x4 matrix;
+    matrix.translate(-m_bufferGeometry.x(), -m_bufferGeometry.y());
+    return matrix;
+}
+
 Xcb::Property X11Client::fetchShowOnScreenEdge() const
 {
     return Xcb::Property(false, window(), atoms->kde_screen_edge_show, XCB_ATOM_CARDINAL, 0, 1);