The development of our graphics environment over the past year has been directed towards demonstrating the concept of broadcast teletext service, where pages of graphics and text are received in the home over existing television channels. We have developed a graphics editor, Radix, which uses an underlying Core graphics package to create teletext-compatible images. Radix is also used to display these images at arbitrary resolutions by scaling the graphics primitives, selecting the corresponding sizes of fonts and bitmaps, and then precisely adjusting the output video signal. The combination of powerful display hardware and a robust set of software tools has allowed us to rapidly prototype potential teletext features, and to provide these accurate simulations of teletext pages at any resolution. While this general graphics environment does impose some inefficiencies in running graphics applications, they are far outweighed by the ability to quickly respond to changing requirements.
['Douglas F. Dixon']
A core graphics environment for teletext simulations