A rendering R may be built up pixel by pixel. Each pixel is visited once. Throughout this section, simple graphs are presented as examples, to reduce clutter. The solutions presented, generally, handle more sophisticated problems well. Some of the interval bounds, and graphs, given may seem optimistic. Keep in mind that when each free variable, namely x and y, appears at most once within an evaluation, optimal bounds are produced, using constant interval arithmetic.
| Jeff Tupper | March 1996 |