On 12/14/20 6:28 AM, Paul Koning via cctalk wrote: >> Is it really an overstrike? They look simply like different characters. >> At least, I didn't (probably missed it) how they can be generated out of >> the available ones... > > I wondered too. General overstrike requires a bitmap display, or some sort > of persistent display. Paper is an example; a Tek 4010 would also handle > overstrike since it uses a storage tube. And PLATO terminals did overstrike > just fine since they are bitmap displays with per-pixel memory.
Back in the day (why is everything now "back in the day"?), I wrote the firmware for a Fortune Systems text terminal. The requirement was for a certain degree of NAPLPS/Videotex compatibility. Combining certain characters was done via lookup in the character generator ROM, not by combining them as graphical characters. I suspect that this was the method used for a large number of terminals, such as the Telidon units. --Chuck
