@chestnutlabs/gcode-preview-vue

Thin Vue 3 integration for the Chestnut Labs G-code viewer: parse .gcode / .gcode.3mf off the main thread, render an interactive Three.js toolpath (layers, scrub, per-file build plates, honest live progress), and never block your UI. This package is glue only — the engine lives in @chestnutlabs/gcode-parser, @chestnutlabs/gcode-renderer-three, and @chestnutlabs/toolpath-core (design: DD-007).

npm install @chestnutlabs/gcode-preview-vue three

(three is a peerDependency of the renderer, supported range ^0.178.0 — npm ≥ 7 installs it automatically; pnpm/yarn users add it explicitly. See the support policy.)

Two adoption levels, one implementation (the component is a shell over the composable):

Ready-to-use component

<script setup lang="ts">
import { GcodePreview } from '@chestnutlabs/gcode-preview-vue';
import { shallowRef } from 'vue';

const file = shallowRef<File | null>(null);
</script>

<template>
  <input type="file" accept=".gcode,.3mf" @change="file = ($event.target as HTMLInputElement).files?.[0] ?? null" />
  <div style="height: 70vh">
    <GcodePreview :source="file" @ready="(s) => console.log(`${s.segments} segments`)" />
  </div>
</template>

That is a complete viewer. The full surface is optional props with sensible defaults:

| Prop | Purpose | |---|---| | source | Uint8Array \| ArrayBuffer \| File — changing it re-parses | | parse-options | wire options (limits, dialects, containers, plate selection) | | build-volume | consumer-configured plate — wins over file-discovered geometry; discovery is then emitted, not applied | | quality | 'auto' \| 'lines' \| 'tubes' | | color-mode | single / by-tool / by-feature (feature coloring is capability-gated — listen for error) | | layer-range / scrub / show-travel | clipping controls | | progress | a DD-006 ProgressObservation — drives the honest live-progress overlay (marker for byte-exact, uncertainty band for approximate, gray when stale) | | create-worker | worker factory escape hatch (see below) |

Emits: ready, parse-error, parse-cancelled, parse-progress, build-complete, quality-fallback, machine-geometry-mismatch, machine-geometry-discovered, progress-presentation-changed, disclosure, error. The underlying handle is exposed for template refs (ref.preview).

Headless composable (build your own controls)

import { useGcodePreview } from '@chestnutlabs/gcode-preview-vue';

const preview = useGcodePreview();          // in setup(); auto-disposes with the scope
// bind: <canvas :ref="(el) => (preview.canvasRef.value = el as HTMLCanvasElement)" />
await preview.parse(bytes);                 // worker parse + progressive preview
preview.controls.setLayerRange(0, 42);      // scrub / colors / quality / bed / frame ...
preview.observeProgress(obs);               // DD-006 live progress (tick ~1 Hz for staleness)
preview.state;                              // shallow read-only reactive summaries
preview.raw.session; preview.raw.renderer();// escape hatches (non-reactive)

The composable owns the sharp edges: dispose-on-unmount/HMR, SSR-import safety, canvas resize (ResizeObserver + fallback), and a strict reactivity boundary (toolpath buffers are never proxied).

Workers: default and custom (both first-class)

Default (zero setup): the batteries worker — all supported slicer/firmware dialect adapters plus .gcode.3mf container support — is created automatically via the bundler-native new Worker(new URL(...)) pattern. Vite resolves this out of the box (this path is exercised by the repo's Vite demo and consumer fixture).

Custom (smaller builds / custom adapters / strict CSP / other bundlers):

useGcodePreview({
  createWorker: () => new Worker(new URL('@chestnutlabs/gcode-parser/dist/worker-slim.js', import.meta.url), { type: 'module' })
});
// or your own worker built with createWorkerHandler(...) — see the parser package docs

Linked-workspace development note: Vite consumers using file: links should add every @chestnutlabs/* package the worker pulls in to optimizeDeps.exclude (installed tarballs/registry packages need no configuration).

Capability honesty

Everything the engine reports as inferred/approximated/unavailable stays that way at this layer: feature coloring refuses rather than fabricates, live progress shows a band instead of a fake-precise marker, and decimation is disclosed via the disclosure emit — surface it.

Support

.gcode (Marlin/Klipper/RepRap-flavor; PrusaSlicer, Orca/Bambu, Cura annotations), .gcode.3mf (sliced-plate export; multi-plate via parse-options.plate), per-file build plates, multi-tool/AMS color, object exclusion, arcs. See the repository's docs/compatibility/dialects-and-containers.md for the evidence-dated matrix and docs/reference/progress-signal-contract.md for the live-progress contract.