annatar VS piston

It's certainly more convenient. Man, we really need a free alternative. I've used annatar to make some basic memes at the command line, but it's quite limited

Well, it depends on how you use it; writing to an image buffer isn't much less efficient than writing to any normal buffer (in fact, although displaying your scene to a window efficiently is important, your main bottleneck will be the actual ray tracing loop). You may want to read this article for a practical example of using an ImageBuffer to create and draw a texture with Piston. Other window backends you could use, apart from pixels which was already mentioned in another comment, include minifb and Mini GL, though I haven't personally used them.

And I really like generic systems where you can create a lot of different things. A program that interested me is Piston (https://github.com/PistonDevelopers/piston), I haven't researched it in depth yet, but the concept of being able to create several things with a base and different modules is very interesting

Try Piston

I haven't seen too much on Piston. No idea how active or recent these projects are but I'm still interested in working with it.

Check out their homepage, https://piston.rs, they even show off some great examples of how their library has been used!

Before I could implement the display output, I needed something to draw the images onto. There are quite a few Rust crates available to create a GUI window and update it with 2D graphics. Most of these are of course intended for making games, and also include ways of getting key presses as input, which I'll also need. I looked at Piston, which I've used before on other projects, Macroquad, which also supports web assembly as well as desktop targets, Pixels, which is intended specifically for 2D games, and Minifb, which is also specifically for 2D applications, but is much simpler. I also tried out libretro, which is specifically made for video game emulation, but I found it much more restrictive than the others because of it's narrow focus.

Depends on my goals. I year ago I wanted to learn rust, so I used piston for a gamejam. (There are several rust engines including bevy, piston, amethyst. They probably vary in quality, features, and constraints.) Piston was a terrible experience because compilation is slow even on that tiny project.

Piston