Bugfix calculation of string center position: Strings shown on the right side at surface mode use special characters ('\016' and '\017') to switch font size. Headline strings like "Desaturation" could also be set to the target font directly, because they do not contain mixed font sizes, but nethertheless they are using the special characters. The function calculating the offset needed to display the strinter with center alignment did not consider the small font size => misalignment during string display. To avoid this an evaluation of the special characters has been added to the helper function.