A control device coupled to a projector that applies distortion correction to input image data to generate corrected image data and projects a corrected image includes a generating section configured to apply, based on correction data indicating content of the distortion correction, the distortion correction to reference image data indicating a reference image including a plurality of lattice points to generate preview image data indicating a preview image, a display section configured to display the preview image, an accepting section configured to accept enlarging operation, selecting operation for selecting a lattice point set as a correction target among a plurality of lattice points included in the preview image to be enlarged, and changing operation for changing a position to the lattice point to be selected, and a transmitting section configured to transmit a changing command for changing the distortion correction generated according to the changing operation to the projector.