PURPOSE: To deform a character image with high quality by executing control so that an end point can not be moved even at the time of moving, correcting, and deforming a curve definition vector next to the end point.

CONSTITUTION: At the time of moving and deforming a curve defining vector Q2 (or Qn-2) next to the end point of a B spline curve approximating the outline of a character, a curve defining vector Q1 (or Qn-1) of the end point is moved according to the movement of the curve defining vector Q2 (or Qn-2) so that the end point, that is, a sample point P1 (or Pn-1) can not be moved. The curve defining vector Q2 (or Qn-2) next to the end point is moved so that a curve defining vector Q2' (or Qn-2') after movement can be held, and a curve defining vector Q1' (or Qn-1') after movement of the curve defining vector Q1 (or Qn-1) is calculated by using the position and the sample point P1 (or Pn-1). The B spline curve approximating the outline can be generated by changing those curve defining vectors.