Color display having selectable off-on and background color control

Claim 1

In a system for displaying information in color on a raster scan medium, the system including controller means for providing control signals, means responsive to said control signals for supplying in sequence, signals representative of the information to be displayed as an array of on and off dot elements on the raster scan medium, first means responsive to said control signals for supplying first color signals specifying the color of goups of contiguous dot elements forming a subarray when said dot elements are on, and background select means for supplying alternate color signals, the improvement comprising: second means responsive to said control signals for supplying second color signals specifying the color of the groups of contiguous dot elements when said dot elements are off; means responsive to said control signals for supplying activating signals indicating an active area is being scanned on said raster scan medium; and gating means responsive to said signals representative of the information to be displayed and to said activating signals for coupling to said raster scan medium said first color signals when said dot elements are on and said second color signals when said dot elements are off and to said absence of said activating signals for coupling to said raster scan medium said alternate color signals.