Mandelbrot rewrite
The fast-bitmap work needed something heavier than a flood-fill to prove it. A Mandelbrot viewer is a convenient brute: lots of independent pixels, an obvious picture when you get it wrong, and a status line that tells you whether the new drawing path was worth the trouble.
This build reports the two times separately. Generation of the set, in double precision Pascal, took 566 ms. Putting that image on the screen took 37 ms. Display is no longer the bottleneck, which is what the bitmap notes were for.