simage

A small 2D graphics library built around a typed Scene (draw list) and a Renderer trait. Front ends build a simage::scene::Scene via RAII builders; renderers replay it through the trait.

Outputs:

• Raster — tiny_skia::Pixmap via PixmapRenderer (in terminal).
• Terminal display — Kitty graphics protocol, DEC Sixel, or 24-bit ANSI half-blocks (▀), chosen automatically per the active terminal.
• PDF — vector path output via PdfRenderer, with text rendered as outlined glyph paths.
• Animation — terminal alt-screen + raw-mode driver with key polling.

Designed to be shared between teaching tools that need to display geometric images: originally extracted from spython and intended for use in sgleam.

Pipeline

front end         simage::scene::Scene            simage::renderer::Renderer
─────────         ────────────────────            ──────────────────────────
build via    →    Vec<Element>             →     PixmapRenderer (terminal)
RAII guards       (Path, Clipped, Text, ...)      PdfRenderer    (PDF)
                                                  your impl      (custom)

A Path carries (style, verbs, coords) — verbs is a Vec<Verb> (a #[repr(u8)] enum: Move=0, Line=1, Quad=2, Cubic=3) consuming 2/2/4/6 floats per verb from coords. The wire format carries the same bytes (verbMove/verbLine/verbQuad/verbCubic in schema/frame.capnp); the boundary parses them back into typed verbs and rejects unknown bytes.

Arcs are pre-expanded to cubics in PathBuilder::arc_to, so every renderer only sees move / line / quad / cubic primitives. Paths and clip scopes are RAII: Scene::path returns a PathBuilder that commits the path on drop; Scene::clip / Scene::clip_rect return a ClipBuilder that accumulates the elements drawn inside the clip and commits a single Element::Clipped { clip, elements } on drop — balanced nesting is structural, not bookkeeping.

Example

use simage::scene::{Scene, PathStyle, Rgba};

let mut scene = Scene::new(40.0, 30.0);
{
    let mut p = scene.path(PathStyle {
        fill: Rgba { r: 0, g: 0, b: 255, a: 1.0 },
        ..PathStyle::default()
    });
    p.move_to(0.0, 0.0);
    p.line_to(40.0, 0.0);
    p.line_to(40.0, 30.0);
    p.line_to(0.0, 30.0);
}

simage::terminal::show_image(&scene);          // terminal
let pdf: Vec<u8> = simage::pdf::render_to_pdf(&scene);

License

Dual-licensed under MIT or Apache-2.0.