Procedural graphics generation in C
blog.noctua-software.com
blog.noctua-software.com
The owner the blog http://fractalyze.blogspot.com/ has probably also done something similar. He produce a lot of image, I found some of them inspiring.
From the code samples it appears more that the author has created a DSL using C macros than providing a library. Such a bummer.
Here, however I find your critique in bad taste and poorly thought out for code whose main value is the art generated by code, where brevity and simplicity of the code base is a value in itself.
There is no one true way to write code. Global state is not an evil in itself unless it causes hidden side-effects. For small single threaded programs a large global state can simplify things a lot.
It's like a lumberjack grumbles to an artisan wielding a penknife that it's far too small to cut down a tree.