at step 805 is yes the above calculation is carried out for all the i j the program proceeds to step 807 to be terminated in relation to the operation shown in fig8 how the bezel correction is effected when an image is displayed over e g two adjacent display devices is explained with reference to fig9 a and 9b in fig9 a and 9b reference numeral a designates a physical display area of a display device b a frame including a border and bezel portions and c a line drawn over two adjacent display devices when the x y coordinates of the point p x y is obtained at step 802 in fig8 the point p x y is displayed in the display area a of a certain display device the point p 39 on the enlarged x y coordinates obtained at step 803 in fig8 though not shown is displayed in a virtual enlarged display area expressed by a broken line d in fig9 a then the virtual enlarged display area is shifted by 1 u03b1 2 in the direction to the origin 0 0 as shown in fig9 b the coordinates at that time are those obtained at step 804 in fig8 as will be clear from fig9 b the virtual display area d and the actual display area b substantially overlap with each other.