bloomdot

Render images as monochrome Unicode braille art on the command line.

bloomdot reads a local image or URL, packs every 2×4 pixel block into a single braille code point (U+2800–U+28FF), and prints the result. Raster formats are decoded via image; SVG inputs are rasterized through resvg before sampling.

Install

From source:

cargo install --path .

Or run it directly from the workspace:

cargo run --release -- <input> [options]

Usage

bloomdot <input> [--width N] [--threshold N] [--invert] [--alpha-cutoff N]
                [--rotate DEG]
bloomdot animate <input> <degree-step> [--frame-delay-ms N] [--no-loop]
                [--export-file PATH]

<input> is either a local image path or an http(s):// URL. Remote responses are capped at 10 MiB.

Flag	Default	Description
-w, --width	40	Output width in braille cells (each cell is 2 pixels wide).
-t, --threshold	180	Luminance below this value becomes ink.
--invert	off	Treat light pixels as ink instead of dark ones.
--alpha-cutoff	16	Alpha values below this are treated as blank.
--rotate	0	Rotate the source image clockwise before rendering.
--no-loop	off	Stop animation after one full rotation.
--export-file	unset	Write one full rotation of animation frames to a text file.

Examples:

bloomdot logo.png --width 60
bloomdot https://example.com/icon.svg --invert
bloomdot photo.jpg --threshold 128 --width 80
bloomdot logo.png --rotate 90
bloomdot animate logo.png 10 --width 60
bloomdot animate logo.png 10 --no-loop
bloomdot animate logo.png 10 --export-file frames.txt

Library

bloomdot is also a library. The main entry points are render_source (load and render in one step) and render_image (render an in-memory image::DynamicImage):

use bloomdot::{InputSource, RenderOptions, render_source};

let art = render_source(
    InputSource::parse("logo.png"),
    RenderOptions::default().with_width(60),
)?;
println!("{art}");

Trivia

The name comes from a jingle in a 90s Brazilian appliances ad that went "bloom bop" — when I was reaching for a word to pair with "dot", that jingle came straight to mind. You can hear it here, at 0:27.

Development

cargo test
cargo run -- <input>