Is it desirable to have option to generate images with black background? #351
Description
The code currently has the ability to generate images with backgrounds gaussian noise, plain (white), quasicrystal with background_type parameter 0, 1 and 2 respectively.
Is it desirable to have an option to generate images with 'black' background? Perhaps if background_type parameter == 4?
Or rather, this could/should be done with simple image processing operation of inverting image colors using image processing libraries?