drawing image shown in 701 in fig7 is drawn in the drawing image data area of the ram 33 all the drawing images which have been drawn are converted to bit map next the cpu 31 executes the process of generating the attribute drawing image of one page portion equivalent to one page of the drawing command in the process of generating the attribute drawing image a drawing area which is formed by the same drawing image as the drawing image drawn in the drawing image data area is formed in the attribute drawing image area the drawing area is filled daubed by a characteristic value an eigen value for instance as the cpu 31 distinguishes the 701 in fig7 as a pattern drawing image the cpu 31 forms a drawing area formed by a drawing image same as the drawing image of 701 in fig7 in the attribute drawing image area of the ram 33 and an attribute drawing image area of 801 in fig8 is formed by filling with a characteristic value corresponding to the pattern drawing for generating the attribute drawing image it is necessary that the cpu 31 distinguishes a type of drawing in the drawing command including information such as a type of drawing and.