Minecraft map art maker and generator: image in, palette-optimized schematic out. It runs entirely in your browser, and it is live at https://b8b7.live/arachne/.
Arachne is in beta. The math is tested and the output is verified in game. The remaining rough edges are mostly cosmetic.
- Turns a picture into a map art schematic for survival or creative building, staircased or flat, from a single map up to a 16x16 grid.
- Prices every block choice by what it costs to build and tear down with the tools you carry: tier, Efficiency, Silk Touch, haste, flying, and whether the block drops itself when broken.
- Dithers with error diffusion (Floyd-Steinberg, Jarvis, Burkes, Stucki, Atkinson, Sierra Lite), ordered patterns, and color mixing based on Joel Yliluoma's arbitrary-palette positional dithering. An optional refinement pass optimizes for viewing distance using the S-CIELAB perceptual metric of Zhang and Wandell (1996; journal version).
- Puts text on the map, with or without a picture behind it: 142 free fonts served from the site itself, crisp one-color letters at sign size or dithered with the picture above it, outline, shadow, underline, gradient, turn and mirror, dragged into place on the preview.
- Handles transparency the way the game does: holes place no blocks, and pixels along a transparency edge are quantized against the shades the game can render there.
- Counts the filler and noobline blocks a build needs alongside the art blocks, in the summary and on the build sheet, and lets you pick the filler block from a searchable, version-aware list.
- Targets any release from 1.13 to the current one. The palette, the blocks on offer, and the DataVersion your files carry all follow the release you pick.
- Exports a .litematic for Litematica, named so it shows under its own name in the schematic list, or a vanilla structure .nbt that Litematica and WorldEdit both read. Split per map panel with correct reference rows, plus optional map data files and a plain-text build sheet. Or skip the blocks: the map.dat mode writes map files for a world save using every color and shade the game has, including the one no block can make.
- Keeps your data yours. The image never leaves your browser, the site has no backend, no analytics and no tracking, and presets save inside your own browser. The web server keeps an ordinary request log for security, the same as any website.
The harvest cost formulas implement the game's own block-breaking
mechanics (tool tier and material multipliers, Efficiency and haste
scaling, the per-break tick delay), read from the unobfuscated 26.x
client. The Minecraft Wiki's breaking
article documents the same
formulas if you want to check them independently. Per-release palette
and block availability are extracted from Mojang's published files by
data-pipeline/, and the per-release map
color counts are cross-verified against three independent sources in
data-pipeline/research/map-color-versions.md.
web/ the app: TypeScript shell, canvas preview, worker
core/ Rust compute core: quantize, dither, solver, export
wasm/ the thin wasm-bindgen boundary between the two
data/ generated block and color data, committed
data-pipeline/ build-time extraction from the game's own files
golden/ pinned fixtures the test suites verify against
data/ and the two atlas files under web/public/ are pipeline
output, committed so the app builds without the pipeline or its
inputs. media/ holds README assets.
You need Node 22 (web/.nvmrc) and rustup. rust-toolchain.toml
pins the Rust version, target and components, and rustup installs
them on first use; npm ci installs the pinned
wasm-pack alongside the
other dev tools. The crates build on Rust 1.85 or newer if you use
your own toolchain.
cd web
npm ci
npm run build # builds the wasm, copies data, bundles
For development, npm run dev starts a dev server (it builds the wasm
package on first run). After Rust changes, npm run wasm regenerates
it.
./verify.sh # the whole gate: cargo, tsc, pages, e2e, mobile
The Rust suites (cargo test --workspace) carry the logic tests and
golden fixtures. The pages leg regenerates the two content pages and
checks its own output. The e2e and mobile legs drive a real browser
against the dev server, so they need system chromium (apt install chromium on Debian and Ubuntu) and npm run dev already running in
another terminal; without those, cargo, tsc and pages still verify
everything except browser behavior.
This source ships two ways. The running site's footer offers an archive of the exact build you are using, and the GitHub mirror carries one commit per published build, tagged with the build id the footer shows. Either one is the corresponding source for the build, offered under the license below.
Release notes for every published build are on the site at https://b8b7.live/arachne/changelog/ and in the Atom feed at https://b8b7.live/arachne/feed.xml. This mirror does not use GitHub Releases.
The FAQ lives at https://b8b7.live/arachne/faq/. The community Discord lives at b8b7.live/discord: help with a build plan, finished map art, and release notes for every published build.
Bug reports are welcome on the GitHub issue tracker or by mail to arachne@b8b7.live. Development happens outside this mirror, so a pull request has no branch to merge into; if you send one anyway, or attach a patch to an issue, it will be read, and carried into the next build with credit if it fits. CONTRIBUTING.md has the details, and SECURITY.md says how to report a vulnerability.
Copyright (C) 2026 b8b7. Licensed under GPL-3.0-only; see LICENSE. Arachne began as a study of rebane2001/mapartcraft (GPL-3.0) and inherits its license with gratitude. The two tools have since diverged in most of what they do, but the kinship is still live: Arachne imports mapartcraft preset links, and the table that decodes them is built by reading mapartcraft's own color data. Block textures and game data are extracted at build time from Minecraft's own files and remain the property of Mojang.