Abstract: A coordinate input device is used in document processing to input user instructions including display coordinates of the display frame as specified by the user.

Abstract: A video-data processor is disclosed in which a video data produced from the laser disk or the like is processed in four stages of video memory. The video data is first A/D converted and written into a first video memory. Then, the video data in the first video memory is subjected to the special effect such as mosaicking and written into a second video memory. A part of the video data in the second video memory is cut out, projected and written into a third video memory, in which the video data, graphics and letters visually projected are combined. A part of the resulting data is cut out, projected and written into a fourth video memory as a window. The data thus projected as a window is displayed on a display unit from the fourth video memory. The visual projection, window projection and the special effect between the video memories are defined to realize the special effect, scroll or partial cut-out of the video data in a multi-window environment.