The HTML parameter zRulerVisible=1 is used to display the Ruler panel in the Zoomify Image Viewer. Additional parameters enable setting choicelist values as zoom percents or magnification levels as well as selection of units. Unit options include: 'Ym', 'Zm', 'Em', 'Pm', 'Tm', 'Gm', 'Mm', 'km', 'hm', 'dam', 'm', 'dm', 'cm', 'mm', 'um', 'nm', 'pm', 'fm', 'am', 'zm', 'ym', 'pixels' (default). See the Parameter List in the Documentation folder for details.