Image display system for controlling the scroll of a partial image on a display screen

摘要

An image display system is disclosed which includes an image filing device to pre-store data on the entire area of a large sized image; a CRT unit to partially display this large sized image on its display screen at the same scale; and an image memory to temporarily store a partial image of the large sized image, that will be displayed on this CRT as well as its surrounding image. When display area scrolling is directed by a scroll direction input device, image information which is newly required due to the given scrolling operation is read out under the control of the CPU, and the unnecessary image information is replaced or written over by the new image information, with semi-realtime, in the memory area in which the image information which became useless due to the scrolling operation had been stored in the image memory. Thus, the display image area concerning the scroll and its surrounding image area always prepared in the image memory, thereby allowing for a smooth scrolling operation.