libshimmer

Animated status lines for terminal UIs, paced by the host's work.

A host makes a Shimmer from one of the stock recipes, tells it what the host is doing and how hard it works, and each frame draws the status line it paints: a mark, the caption's letters, and a tail, over a backdrop of background colors. Paint is plain data; the ratatui feature converts it into ratatui 0.30 spans and shades a ratatui buffer. libshimmer reads no clock and keeps no global state: the host passes the time between frames, and paint depends only on the recipe, the seed, the commands so far, and the colors and motion the host paints with.

use std::time::Duration;

use libshimmer::{Glyphs, Intensity, Motion, Palette, Rgb, Shimmer, Spell, stock};

let recipe = stock::named("Lava Lamp").expect("a stock recipe");
let mut shimmer: Shimmer = Shimmer::new(recipe, 7, Glyphs::BASE)?;
shimmer.set_spell(Spell::Busy);
shimmer.show("Compiling");

// Each frame:
shimmer.set_intensity(Intensity::new(tokens_per_second / 100.0));
shimmer.advance(since_last_frame);
let palette = Palette { fg: Rgb(208.0, 208.0, 208.0), bg: Rgb(21.0, 21.0, 21.0) };
let row = shimmer.status(palette, Motion { mark: true, letters: true });
let spans = row.spans(); // with the `ratatui` feature; `row.cells()` otherwise
row.shade(area, buf);

// When the work ends:
shimmer.set_spell(Spell::Idle);

SPEC.md specifies the design. MIT-0 licensed.