Displaying Overstruck Characters Using Programmed Symbols
Original Publication Date: 1986-Oct-01
Included in the Prior Art Database: 2005-Mar-09
Typically, displays which refresh from a mapped regeneration buffer cannot display overstruck characters. Each character to be displayed must be predefined and stored in either a ROS (read-only storage) or RAM (random-access memory) character set generator. The display logic selects one of these predefined characters per character position on the display. This article describes a technique to generate dynamically a definition of an overstruck character, and store it in a programmed character set. When providing text function on a traditional mapped character display, the data stream is stored first in an unmapped buffer, shown here as the Text Buffer 10. This buffer contains displayable characters and control codes which operate on the data to format the screen of the Video Display 12.