1. An image processing apparatus comprising: an anchor point information extraction unit configured to decide coordinates of anchor points and attributes of the anchor points based on a plurality of predetermined extraction rules and a sequence of coordinate points that expresses an outline of image data; a tangential direction decision unit configured to decide tangential directions at an anchor point of interest based on the attribute of the anchor point of interest and coordinate points which are located within a predetermined range from the anchor point of interest; a control point coordinate calculation unit configured to calculate control point coordinates based on the tangential directions and the coordinates of the anchor point of interest; and a data output unit configured to output information including the coordinates of the anchor points and the control point coordinates.