@cadview/dwg

DWG file format support for @cadview/core via LibreDWG compiled to WebAssembly.

Converts DWG files to DXF entirely in the browser — no server required.

License

GPL-3.0-only — This package uses LibreDWG which is GPL-licensed. Using @cadview/dwg in your application makes the combined work subject to GPL-3.0 terms. If you cannot comply with the GPL, do not use this package.

@cadview/core and the framework wrappers (@cadview/react, @cadview/svelte, @cadview/vue) remain MIT-licensed and have zero dependency on this package.

Installation

npm install @cadview/dwg @cadview/core

Quick Start

Register the dwgConverter with CadViewer to automatically handle DWG files alongside DXF:

import { CadViewer } from '@cadview/core';
import { dwgConverter } from '@cadview/dwg';

const viewer = new CadViewer(canvas, {
  formatConverters: [dwgConverter],
});

// loadFile() and loadBuffer() now handle both DXF and DWG
await viewer.loadFile(file);

With framework wrappers:

// React
import { CadViewer } from '@cadview/react';
import { dwgConverter } from '@cadview/dwg';

<CadViewer file={file} formatConverters={[dwgConverter]} />

<!-- Svelte -->
<script>
  import { CadViewer } from '@cadview/svelte';
  import { dwgConverter } from '@cadview/dwg';
</script>

<CadViewer {file} formatConverters={[dwgConverter]} />

<!-- Vue -->
<script setup>
import { CadViewer } from '@cadview/vue';
import { dwgConverter } from '@cadview/dwg';
</script>

<CadViewer :file="file" :format-converters="[dwgConverter]" />

Standalone Usage

You can use the conversion functions directly without CadViewer:

import { convertDwgToDxf, isDwg, getDwgVersion } from '@cadview/dwg';
import { parseDxf } from '@cadview/core';

// Check if a buffer is a DWG file
const buffer = await file.arrayBuffer();
if (isDwg(buffer)) {
  const version = getDwgVersion(buffer); // e.g. "AC1032"
  const dxfString = await convertDwgToDxf(buffer);
  const doc = parseDxf(dxfString);
}

WASM Preloading

The LibreDWG WASM module (~2-5 MB) is lazy-loaded on the first DWG conversion. To avoid the delay when the user first opens a DWG file, preload it on app startup:

import { initWasm } from '@cadview/dwg';

// Preload on app startup
initWasm();

// Or from a CDN
initWasm({ wasmUrl: 'https://cdn.example.com/libredwg.wasm' });

API

dwgConverter: FormatConverter

Pre-configured format converter for use with CadViewer's formatConverters option. Detects DWG files by magic bytes and converts via LibreDWG WASM.

isDwg(buffer: ArrayBuffer): boolean

Detect DWG format by checking magic bytes (AC10 prefix + two ASCII digits). Returns false on any error.

getDwgVersion(buffer: ArrayBuffer): string | null

Extract the 6-character DWG version string (e.g. "AC1032"). Returns null for non-DWG buffers.

getDwgReleaseName(version: string): string | null

Get the human-readable AutoCAD release name for a version string (e.g. "AC1032" → "R2018").

convertDwgToDxf(buffer: ArrayBuffer, options?: ConvertOptions): Promise<string>

Convert a DWG buffer to a DXF string. Lazily initializes the WASM module on first call.

Options:

initWasm(options?: WasmOptions): Promise<void>

Pre-initialize the WASM module. Safe to call multiple times. Automatically retries on failure.

isWasmReady(): boolean

Check if the WASM module is loaded and ready.

DWG_VERSIONS: Record<string, string>

Map of known DWG version strings to AutoCAD release names:

Minimum supported version: AC1012 (R13).

Building the WASM Module

The WASM module must be compiled from LibreDWG using Emscripten before DWG conversion will work at runtime.

Prerequisites:

• Emscripten SDK (emsdk)
• Git (for LibreDWG submodule)

# Add LibreDWG as a git submodule (one-time)
git submodule add https://github.com/LibreDWG/libredwg.git packages/dwg/wasm/libredwg/

# Build the WASM module
pnpm --filter @cadview/dwg build:wasm

This generates dist/libredwg.js and dist/libredwg.wasm.

License

GPL-3.0-only. See LICENSE.