Lovely programatic images
This picture was generated in 4 minutes and 30 seconds by version 0.5.0 with cargo run --release 16:
This picture was generated in 12 minutes and 30 seconds by version 0.4.0 with cargo run --release 16:
First, the image is seeded with n * 2 randomly colored pixels, where n is the input.
Then, a random pixel is chosen. The pixel which has already been placed whose color is closest to that pixel is located, and the new pixel is placed as close as possible to the pixel which was located. This process is repeated until the image is filled.
The pixels are not chosen purely randomly, but are instead a random ordering over a color cube with n^2 possibilities for each of R,G,B. These pixels exactly fit into the n^3 by n^3 square canvas, which is then output.
First, all possible colors are generated, and are randomly shuffled.
After the random color is picked, we search through the possible color offsets in ascending order of distance (L2 norm) to find the closest color which has already been assigned. This is pretty fast, since colors are assigned randomly.
Then, to find the location, we search through the frontier of locations which have not been assigned, but which neighbor an assigned location. This is much faster than the previous offset based approach. It's about O(n^0.5), n is the total number of pixels in the image. As a further optimization, we give each initial point its own frontiers, and merge frontiers as the collide. This gives a speedup of about a factor of 3 at size 12.
Overall, the algorithm is about O(n^1.5)
Put the size parameter as the first argument. Currently 1-15 are suppoered.
If you want debugging information, give the frequency (printout per how many pixels) that you want. 10000 seems good on my machine.
The command line interface will likely be upgraded soon.