multimath

Core to create fast image math in WebAssembly and JS.

multimath simplifies creation of small CPU-intensive webassembly modules with fallback to JavaScript implementations.

• It cares about modules init, memory management and other things.
• Has built-in helpers to write webassembly code without additional runtimes.
• Use shared memory to chain webassembly calls without memory copy.

Built-in functions (currently - unsharp mask) are available as examples for your extensions.

Install

npm install multimath

Use

import { MultiMath, unsharp_mask_plugin } from 'multimath'

const mm = new MultiMath()
             .use(unsharp_mask_plugin)
             .use(your_custom_plugin)

// Simple sync call. Will use sync wasm compile. Ok for webworkers.
// Can freeze interface at first call if wasm source is too big.
mm.unsharp_mask(rgba_buffer, width, height)

// Async init, compile all modules at once in async way.
await mm.init()
mm.unsharp_mask(rgba_buffer, width, height)

API

new MultiMath(options)

Create library instance.

const mm = new MultiMath({
  // Options are not mandatory, but you can disable js or wasm
  // implementations for testing
  js:   true,
  wasm: true
})

.use(plugin)

Register new plugin, format is:

{
  name:     String,    // method name to expose on instance
  fn:       Function,  // JS implementation
  wasm_fn:  Function,  // WebAssembly glue
  wasm_src: String     // Base64 encoded WebAssembly module
}

See lib/unsharp_mask_plugin/ as an example implementation.

.init() -> Promise

Optional. Compile all wasm modules asynchronously. Useful when:

1. Wasm module > 4K AND running in the main thread (not in a webworker). Some browsers prohibit sync wasm creation in this case.
2. Many small modules that should all be initialized before first use.

Note: a 3K wasm file initializes in ~3ms.

.<your_method>

All plugins loaded via .use() pin their methods to the MultiMath instance. The best implementation is selected automatically based on browser features and constructor options.

Development

Ways to go with your own plugins:

• See lib/unsharp_mask_plugin/ as an example.
• See how pica uses this library.