I think you might be best to ignore the 8275 chip - this is meant for 'raster' scan devices like TV's and monitors.

As Ijaz mentioned I think your solution is with a DAC (digital to analog converter). The early video games used this technique which is called 'vector scan' - Asteroids was an example of this. Something like a DAC08 chip and two LM398 sample and hold chips (one for the X and one for the Y) along with the 8051 and some software to redraw the vectors at a fast enough rate so the image does not flicker (> 20 times/second).

Search the web for 'Vectrex' which was a consumer video game that used a 6809 cpu and vector scan techniques - there's an explanation of how it all works, schematics and code for games. Even though it is 6809, the method is the sample and you may be able to adapt the code.