An input-mode determination unit determines an input mode to be a graphic mode in the case where the number of sets of coordinates included in a coordinate sequence stored in the coordinate-sequence storage unit is smaller than a predetermined number and points represented by the coordinates are within a predetermined distance range, and otherwise, determines the input mode to be a curve mode. A line-to-draw sequence generation unit generates a line-to-draw sequence according to the input mode which the input-mode determination unit has determined to be.