Resim

Resim is a browser image toolkit built with Rust and WebAssembly.
The repository contains a validated Rust core for RGBA pixel transforms, wasm bindings for browser consumers, and a React demo that exercises the public browser API.

Positioning

Resim is currently positioned as:

• a browser-first image toolkit with a small, explicit public API
• a reference demo for consuming the generated wasm package
• a semver-managed toolkit with a stable 1.x browser API baseline

Crop and rotate remain intentionally out of scope for the current line, but nearest-neighbor resize is included.

Stable API surface

The stable browser-facing surface for the 1.x line is:

• wasm initialization through the default export
• ImageData-first transforms such as brightnessImageData, contrastImageData, and sepiaImageData
• catalog introspection through getTransformCatalog()
• canvas helpers readImageDataFromCanvas and writeImageDataToCanvas

Backward-compatible aliases are kept for older helper names such as readCanvasImageData, writeCanvasImageData, and applyTransformToCanvas.

Current transforms

• grayscaleImageData
• invertImageData
• blurImageData
• brightnessImageData
• contrastImageData
• thresholdImageData
• sharpenImageData
• saturationImageData
• sepiaImageData
• opacityImageData
• gammaImageData
• resizeImageData
• composeImageDataTransforms

The Rust core also exposes apply_transform_sequence for validated multi-step transform composition.

Supported environments

Officially supported today:

• modern evergreen browsers with WebAssembly and ImageData
• bundlers that can consume ESM wasm output generated by wasm-pack --target web
• local development with Rust stable, wasm-pack, Node.js, and npm

Expected bundler behavior:

• the app or package consumer must await the wasm default initializer before calling exports
• the bundler must support loading the generated .wasm asset emitted by wasm-pack
• the current demo is verified with webpack 5

Browser API examples

Parameterized transform:

import {
  default as init,
  brightnessImageData,
  readImageDataFromCanvas,
  writeImageDataToCanvas,
} from "resim";

await init();

const imageData = readImageDataFromCanvas(canvas, ctx);
const transformed = brightnessImageData(imageData, 30);
writeImageDataToCanvas(ctx, transformed);

Chained workflow:

import {
  default as init,
  contrastImageData,
  sepiaImageData,
} from "resim";

await init();

const boosted = contrastImageData(imageData, 25);
const vintage = sepiaImageData(boosted);

Canvas convenience helper:

import { default as init, applyCanvasTransform, TransformKind } from "resim";

await init();
applyCanvasTransform(canvas, ctx, TransformKind.Blur);

The canvas helper remains a convenience API. The primary long-term surface is still ImageData-first.

Demo capabilities

The React demo currently supports:

• preset-driven look selection with one-click apply
• fine-tune inspector controls powered by the wasm-exported transform catalog
• local image upload and sample-image restore
• side-by-side original vs processed comparison
• undo and reset flows
• processed PNG export
• responsive action controls with a custom CSS layout

Versioning and deprecation

Current versioning rules:

• crate and demo versions move together inside this repository
• breaking browser API changes require a major version bump
• minor versions add backward-compatible capabilities within the active major line
• new APIs should be added before old aliases are removed
• renamed browser exports should ship with at least one documented release of overlap

Repo layout

• rust/ contains the Rust core and wasm bindings
• react/ contains the showcase app
• examples/ contains minimal consumption examples
• docs/ contains architecture and troubleshooting notes
• CONTRIBUTING.md covers local setup and release expectations
• CHANGELOG.md tracks shipped changes

Local development

Prerequisites:

• Rust stable with cargo
• wasm-pack
• Node.js with npm

Common commands:

make install
make test
make build
make smoke

For browser wasm integration tests and publish-artifact verification:

make wasm-test
make release-check

Additional docs

• CONTRIBUTING.md
• docs/ARCHITECTURE.md
• docs/TROUBLESHOOTING.md
• examples/minimal-browser/main.js