Here’s another imaging example done with PHP – a Voronoi Diagram. I don’t exactly remember when I wrote this, but it was some time this year. The code doesn’t use any fancy, ultra-efficient algorithm, so it takes several seconds to make a medium-size image on my (old) computer.
The algorithm used is very simple: Iterate through each pixel of the image, and find which reference point it is closest to. Then, set the color of the pixel to the color of the reference point.
Voronoi Diagram with 50 Colors