1. A projector device comprising: a track detection unit that detects a track designated by an optical pointer on a projected image; a region designating unit that designates a specific region based on the track detected by the track detection unit; a determining unit that determines a length as a reference for enlargement of an image portion defined within the region designated by the region designating unit; an image enlarging unit that enlarges the image portion in the region based on the length as the reference determined by the determining unit and a size of an entire image; and an enlarged image projecting unit that projects the enlarged image enlarged by the image enlarging unit.