@oh-just-another/text-wasm

WASM-backed TextShaper for the diagram renderer.

L2. Implements @oh-just-another/renderer-core's TextShaper interface. Until a WASM module is loaded, measure uses a synchronous geometric estimate so first paint isn't blank; loadModule(...) swaps in a real shaper at runtime. No module is bundled — the host picks the engine that matches its font pipeline.

Install

pnpm add @oh-just-another/text-wasm

Quick start

import { WasmTextShaper } from "@oh-just-another/text-wasm";

const shaper = new WasmTextShaper();
await shaper.loadModule("/text-shaper.wasm"); // optional — without it, the fallback estimate is used

// pass into the editor
const editor = new Editor({ textShaper: shaper /* … */ });

Expected WASM exports

interface WasmShaperExports {
  memory: WebAssembly.Memory;
  alloc(bytes: number): number;
  free(ptr: number, bytes: number): void;
  setFont(familyPtr: number, familyLen: number, size: number): void;
  measure(textPtr: number, textLen: number): number; // advance width in CSS px
}

Any toolchain that emits a WebAssembly.Instance matching this shape works (Rust + wasm-bindgen with #[no_mangle] exports, AssemblyScript, hand-crafted .wat, …). Optional glyphMetrics / rasterizeGlyphMSDF exports, when present, feed @oh-just-another/glyph-atlas.