公开(公告)号：DE3475446D1

公开(公告)日：1989-01-05

申请号：DE3475446

申请日：1984-06-25

Applicant: IBM

Inventor： BOWATER RONALD JOHN ,  DAVIS MICHAEL IAN ,  FARR ROBERT WILLIAM ERIC ,  POWELL COLIN VICTOR

IPC: G06G7/163 ,  G09G5/06 ,  G09G1/28 ,  G09G1/16

Abstract: A terminal includes a raster-scan display device and a refresh buffer having bit planes (1-6) each with a respective bit storage location corresp. to each addressable pel position on the display screen. The bit planes are addressed in coordination with the line-by-line scanning of the display device to provide multi-bit per pel output data defining the colour and/or intensity of each pel on the screen. In order to store alphanumeric data on such a terminal, high resolution luminance data, defining alphanumeric characters each as a selection of 'on' bits within a respective character box, is stored in a bit plane (luminance plane 1). At least one further bit plane (attribute plane 2) is used to store low resolution colour data which defines at least the colour and/or intensity of the foreground and background of the characters.