+ * @brief Calculates the vertical line's offset for a given line.
+ *
+ * @pre @p lineIndex must be between 0 and the number of lines (both inclusive).
+ *
+ * @param[in] lines The laid-out lines.
+ * @param[in] lineIndex Index to the line.
+ *
+ * @return The vertical offset of the given line.
+ */
+float CalculateLineOffset( const Vector<LineRun>& lines,
+ LineIndex lineIndex );
+
+/**