Graphic options Xmax and Ymax are related with your external display devices (like printers...) and mostly reflect their limitations - paper size could be an example. Typically, the default dimensions of the graphics output area are the same as the dimensions of the device. This is usually true for display devices. For those devices, the default value of HSIZE and VSIZE is 0. However, for hardcopy devices, the XMAX, YMAX values represent the external boundaries of the output medium (such as a sheet of paper). If these devices need a margin, HSIZE, VSIZE and HORIGIN, VORIGIN are assigned default values and the default graphics output area is somewhat smaller than the device's display area.