| 摘要 |
PROBLEM TO BE SOLVED: To provide a display device that realizes an undoing function for performing an undoing process for each indication tool and is easier to handle.SOLUTION: An electronic blackboard 1 comprises: a touch panel 3 for accepting a drawing operation by a plurality of pen devices 5; a display unit 2 for performing display pertaining to the accepted drawing operation; pen identification units 35, 45 for acquiring identification information on the plurality of pen devices 5; a storage unit 44 for storing, for each of the acquired identification information on the pen devices 5, a history pertaining to the drawing operation by the plurality of pen devices 5; a control unit 43 for specifying one of the stored histories pertaining to the drawing operation by the plurality of pen devices 5; and an undoing processing unit 47 for performing an undoing process for returning display by the display unit 2 pertaining to the drawing operation to its original state tracing the specified history in reverse order. |
