PURPOSE: To generate-characters of high quality whose internal areas are painted out without deforming the contour patterns of original character patterns by automatically judging the inside and outside of an optional character contour pattern.

CONSTITUTION: Data (a, b) which are newly added to data (X, Y) in a given contour data group while precedent and following data are referred to are calculated, the new data (a, b) are added to the data (X, Y), and the resulting data are stored as (X, Y, a, b); and the data (a, b) of the stored data are referred to and the part where X appears for the 1st time for Y to the point where the addition result becomes (a, b)=(0, 0) is judged as the inside of a closed area and painted out. Therefore, the (a, b) are only calculated at the time of X-directional sweeping as to the certain Y, so the inside can be painted out without deforming the contour pattern of the original character pattern.