clj-figlet

      _  _        __ _       _      _
  ___| |(_)      / _(_) __ _| | ___| |_
 / __| || |_____| |_| |/ _` | |/ _ \ __|
| (__| || |_____|  _| | (_| | |  __/ |_
 \___|_|/ |     |_| |_|\__, |_|\___|\__|
      |__/             |___/

A native Clojure re-implementation of FIGlet — the classic ASCII art text renderer. No shelling out, no external dependencies beyond Clojure itself. Parses FIGfont files, implements all six horizontal smushing rules, and produces output identical to the reference C figlet.

Why?

FIGlet has been the standard way to render large text in terminals since 1991, but using it from Clojure typically means shelling out to a C binary — which adds a system dependency, a subprocess per call, and makes the output opaque to your program.

clj-figlet is a from-scratch implementation against the FIGfont Version 2 Standard (Cowan & Burton, 1996-97). Fonts load as plain Clojure maps, rendering is a pure function from font + string to string, and the whole thing composes naturally with the rest of the language. No native dependencies, no subprocess, no state.

Quick Start

Add the dependency:

;; project.clj
[com.github.danlentz/clj-figlet "0.1.4"]

;; deps.edn
com.github.danlentz/clj-figlet {:mvn/version "0.1.4"}

Then in your code:

(require '[clj-figlet.core :as fig])

(print (fig/render "standard" "Hello!"))

 _   _      _ _       _
| | | | ___| | | ___ | |
| |_| |/ _ \ | |/ _ \| |
|  _  |  __/ | | (_) |_|
|_| |_|\___|_|_|\___/(_)

Usage

One-shot rendering

(print (fig/render "slant" "Clojure"))

   ________        _
  / ____/ /___    (_)_  __________
 / /   / / __ \  / / / / / ___/ _ \
/ /___/ / /_/ / / / /_/ / /  /  __/
\____/_/\____/_/ /\__,_/_/   \___/
            /___/

Load once, render many

For repeated rendering, load the font once and pass the font map to render:

(def font (fig/load-font "fonts/small.flf"))

(print (fig/render font "OK"))
(print (fig/render font "WARN"))
(print (fig/render font "ERR"))

load-font accepts a classpath resource path, a filesystem path, a File, or a Reader.

Fonts are data

A loaded font is a plain Clojure map. Inspect, validate, modify, and write back:

(:height font)             ;=> 5
(:h-layout font)           ;=> :smushing
(count (:chars font))      ;=> 229
(fig/valid-font? font)     ;=> true

(fig/all-fonts)            ;=> ["3d" "4Max" "Acrobatic" ...]
(fig/write-font font "my-font.flf")

Bundled Fonts

45 fonts ship in resources/fonts/. Here are a few highlights:

standard — the classic

     _                  _               _
 ___| |_ __ _ _ __   __| | __ _ _ __ __| |
/ __| __/ _` | '_ \ / _` |/ _` | '__/ _` |
\__ \ || (_| | | | | (_| | (_| | | | (_| |
|___/\__\__,_|_| |_|\__,_|\__,_|_|  \__,_|

small — compact

 _  _     _ _
| || |___| | |___
| __ / -_) | / _ \_
|_||_\___|_|_\___(_)

doom — clean and modern

______
|  _  \
| | | |___   ___  _ __ ___
| | | / _ \ / _ \| '_ ` _ \
| |/ / (_) | (_) | | | | | |
|___/ \___/ \___/|_| |_| |_|

slant — italic

         __            __
   _____/ /___ _____  / /_
  / ___/ / __ `/ __ \/ __/
 (__  ) / /_/ / / / / /_
/____/_/\__,_/_/ /_/\__/

script — cursive

               o
 ,   __   ,_        _ _|_
/ \_/    /  |  |  |/ \_|
 \/ \___/   |_/|_/|__/ |_/
                 /|
                 \|

graffiti — urban

                      _____  _____.__  __  .__
   ________________ _/ ____\/ ____\__|/  |_|__|
  / ___\_  __ \__  \\   __\\   __\|  \   __\  |
 / /_/  >  | \// __ \|  |   |  |  |  ||  | |  |
 \___  /|__|  (____  /__|   |__|  |__||__| |__|
/_____/            \/

banner — retro block

 #####  ####### ####### ######
#     #    #    #     # #     #
#          #    #     # #     #
 #####     #    #     # ######
      #    #    #     # #
#     #    #    #     # #
 #####     #    ####### #

Roman — classic serif

ooooooooo.
`888   `Y88.
 888   .d88'  .ooooo.  ooo. .oo.  .oo.    .oooo.   ooo. .oo.
 888ooo88P'  d88' `88b `888P"Y88bP"Y88b  `P  )88b  `888P"Y88b
 888`88b.    888   888  888   888   888   .oP"888   888   888
 888  `88b.  888   888  888   888   888  d8(  888   888   888
o888o  o888o `Y8bod8P' o888o o888o o888o `Y888""8o o888o o888o

Colossal — tall digits

888888b.  d8b        888
888  "88b Y8P        888
888  .88P            888
8888888K. 888 .d88b. 888
888  "Y88b888d88P"88b888
888    888888888  888Y8P
888   d88P888Y88b 888 "
8888888P" 888 "Y88888888
                  888
             Y8b d88P
              "Y88P"

ghost — ethereal

             ('-. .-.               .-')    .-') _
            ( OO )  /              ( OO ). (  OO) )
  ,----.    ,--. ,--. .-'),-----. (_)---\_)/     '._
 '  .-./-') |  | |  |( OO'  .-.  '/    _ | |'--...__)
 |  |_( O- )|   .|  |/   |  | |  |\  :` `. '--.  .--'
 |  | .--, \|       |\_) |  |\|  | '..`''.)   |  |
(|  | '. (_/|  .-.  |  \ |  | |  |.-._)   \   |  |
 |  '--'  | |  | |  |   `'  '-'  '\       /   |  |
  `------'  `--' `--'     `-----'  `-----'    `--'

dancingfont — decorative

  ____       _      _   _      ____ U _____ u
 |  _"\  U  /"\  u | \ |"|  U /"___|\| ___"|/
/| | | |  \/ _ \/ <|  \| |> \| | u   |  _|"
U| |_| |\ / ___ \ U| |\  |u  | |/__  | |___
 |____/ u/_/   \_\ |_| \_|    \____| |_____|
  |||_    \\    >> ||   \\,-._// \\  <<   >>
 (__)_)  (__)  (__)(_")  (_/(__)(__)(__) (__)

Doh — enormous

DDDDDDDDDDDDD                        hhhhhhh
D::::::::::::DDD                     h:::::h
D:::::::::::::::DD                   h:::::h
DDD:::::DDDDD:::::D                  h:::::h
  D:::::D    D:::::D    ooooooooooo   h::::h hhhhh
  D:::::D     D:::::D oo:::::::::::oo h::::hh:::::hhh
  D:::::D     D:::::Do:::::::::::::::oh::::::::::::::hh
  D:::::D     D:::::Do:::::ooooo:::::oh:::::::hhh::::::h
  D:::::D     D:::::Do::::o     o::::oh::::::h   h::::::h
  D:::::D     D:::::Do::::o     o::::oh:::::h     h:::::h
  D:::::D     D:::::Do::::o     o::::oh:::::h     h:::::h
  D:::::D    D:::::D o::::o     o::::oh:::::h     h:::::h
DDD:::::DDDDD:::::D  o:::::ooooo:::::oh:::::h     h:::::h
D:::::::::::::::DD   o:::::::::::::::oh:::::h     h:::::h
D::::::::::::DDD      oo:::::::::::oo h:::::h     h:::::h
DDDDDDDDDDDDD           ooooooooooo   hhhhhhh     hhhhhhh

See doc/fonts.md for the complete visual catalog of all 45 fonts.

Any .flf FIGfont file can be loaded — the library implements the full FIGfont Version 2 specification.

The bundled fonts are from the FIGlet distribution and are redistributed under the New BSD License. See resources/fonts/NOTICE for the full license text.

FIGfont Spec Compliance

The implementation follows the FIGfont Version 2 Standard (Cowan & Burton, 1996-97). A copy of the spec lives in doc/papers/figfont.txt.

What's implemented

• Full header parsing (signature, hardblank, height, baseline, max-length, Old_Layout, comment lines, print direction, Full_Layout, codetag count)
• Layout parameter interpretation for both Old_Layout and Full_Layout
• All three horizontal layout modes: full width, fitting (kerning), smushing
• All six horizontal smushing rules:
  1. Equal character smushing
  2. Underscore smushing
  3. Hierarchy smushing
  4. Opposite pair smushing
  5. Big X smushing
  6. Hardblank smushing
• Universal smushing (when no controlled rules are specified)
• Hardblank handling (visible for horizontal fitting/smushing, rendered as spaces in output)
• Required character set (ASCII 32–126 plus 7 Deutsch characters)
• Code-tagged characters (decimal, octal, and hexadecimal code formats)

Not yet implemented

• Vertical fitting and smushing
• Right-to-left print direction
• Control file (.flc) processing
• Word wrapping

Development

lein test           # Run all tests
lein repl           # Start a REPL in clj-figlet.core

The test suite compares rendered output against the reference C figlet binary (install via brew install figlet) across all 45 bundled fonts using common strings, smushing stress cases, regression cases, and randomized generative tests (50 random strings per font per category, 6000+ assertions per run).

Acknowledgments

This library would not exist without the work of the original FIGlet authors. Glenn Chappell and Ian Chai created FIGlet in 1991 as a 170-line C program called "newban" and grew it into something beloved across the internet. John Cowan and Paul Burton later wrote the FIGfont Version 2 Standard — a remarkably well-designed specification that has aged gracefully for three decades. The format is elegant in its simplicity: plain text all the way down, editable in any text editor, portable across every platform, and expressive enough to support hundreds of fonts with a handful of smushing rules. It is a model of what a small, clear standard can accomplish.

The bundled font files are from the FIGlet distribution (New BSD License) and carry their own attribution in their header comments. See resources/fonts/NOTICE for details.

Thank you to Glenn, Ian, John, Paul, Christiaan Keet, and Claudio Matsuoka for creating and maintaining FIGlet over the years, and to the many font designers who contributed to its remarkable library.

License

Copyright © 2026 Dan Lentz

This program and the accompanying materials are made available under the terms of the Eclipse Public License 2.0 which is available at https://www.eclipse.org/legal/epl-2.0.

This Source Code may also be made available under the following Secondary Licenses when the conditions for such availability set forth in the Eclipse Public License, v. 2.0 are satisfied: GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version, with the GNU Classpath Exception which is available at https://www.gnu.org/software/classpath/license.html.