craws-app
GUI
A Tauri 2 + React viewport. Pan and zoom run on the GPU; a slider previews in a fragment shader so the bridge stays idle — measured 165 fps, 21× the naive round-trip.
open-source · Rust · MIT
● pre-alpha — the engine, CLI and MCP server already run
claws + draws · a blazing-fast image editor for developers, written in Rust
Craws is a pipeline editor: an ordered chain of parametrized ops over a tiled, content-hash-cached, linear-light engine. Drive it from this GUI, a headless CLI, CI, or an AI agent over MCP.
fig.01 — pipeline.json · live4 steps · cached · 11.8 ms
craws — IMG_2153.webp — 720×1080 @ 100%
decode→
resize→
exposure→
crop→
grayscale→
draw→
export
open_imagerecompute 48/48
propertiesopen_image
- source
- IMG_2153.webp
- size
- 720×1080
- color
- sRGB → linear f32
- tiles
- 256² · premultiplied
histogram
luminance · RGB
02◢ proof over vibes
Perf claims get numbers, not adjectives.
Every bar is a criterion benchmark on a 24-megapixel photo, release build. When craws grew its own resampler and a SIMD encoder, these are the numbers that moved.
resize · 6000→1920 · lanczos36× faster
before
323 ms
after
54 ms
encode · jpeg q90 · 24MP2.4× faster
before
910 ms
after
375 ms
4-step chain · slider tweak7× faster
before
85 ms
after
11.8 ms
exposure · 24MP · cached580× faster
before
49 ms
after
85µs
measured · 6000×4000 · one machine — the BLAZING contract
03◢ the toolbox
Ten operations. One JSON file.
Every op is one line in a pipeline — composable, versionable, replayable. The same pipeline over the same input returns bit-identical pixels.
resize
Resample
{ "op": "resize", "width": 1600, "filter": "lanczos3" }Own separable resampler — 6× faster than the crate it replaced, with no gamma-space bleed and no dark fringing. One dimension can preserve aspect ratio.
04◢ the content-hash cache
Change one node. Recompute one node.
Each step is a node keyed by the blake3 hash of its inputs and params. Edit a value and the cache works out exactly which tiles of which nodes have to run again — everything upstream is served straight from memory.
decode
#d18a6
recompute
resize
#d1fd0
recompute
exposure
#c1052
recompute
crop
#e20fa
recompute
grayscale
#384ed
recompute
draw
#e217d
recompute
export
#d1929
recompute
[COLD RUN]
cold run — every node computes every tile from scratch
recompute cache hit
05◢ one engine, four ports
The engine has no opinion on who calls it.
domain ← engine; codecs, GPU and AI are adapters behind traits; the CLI, the MCP server and the GUI are equal ports and never know about each other.
craws-engine
tiled · content-hash cache · linear f32 · rayon
domaincodecsgpuai
craws
CLI
craws run pipeline.json — headless, scriptable, deterministic. Format follows the file extension; a timing report follows every run.
no GPU
CI
The CPU path always exists. Drop craws into a pipeline and batch-process on a runner — bit-identical output makes it safe to diff.
craws-mcp
MCP
13 tools over stdio. An agent opens an image, annotates it, exports it — automated documentation figures, the killer use case.