---
title: secondmouseau/swiftjww
framework: Swift Package Catalog
role: article
path: packages/secondmouseau/swiftjww
---

# secondmouseau/swiftjww

📖 **Documentation:** <https://secondmouseau.github.io/SwiftJWW/>

## Install

```swift dependencies: [     .package(url: "https://github.com/SecondMouseAU/SwiftJWW.git", from: "1.0.0"), ], // target: .target(name: "YourTarget", dependencies: [.product(name: "SwiftJWW", package: "SwiftJWW")]), ```

## CLI

``` swift run jww2dxf drawing.jww            # → drawing.dxf swift run jww2dxf drawing.jww out.dxf ```

## Library

```swift import SwiftJWW

let dwg = try JWW.read(contentsOf: url) print(dwg.version, dwg.counts.line, dwg.counts.arc, dwg.bounds as Any)

for e in dwg.entities {     switch e {     case let .line(a, b, layer, color):  …     case let .arc(center, radius, start, sweep, tilt, ratio, full, layer, color):  …     case let .point(at, layer, color):  …     case let .text(at, height, width, angleRad, raw, layer, color):  …   // `raw` is CP932 bytes     } }

let dxf = DXFWriter.string(dwg)          // or DXFWriter.write(dwg, to: url) ```

`JWW.looksLikeJWW(data)` sniffs the `JwwData.` signature.

## Scope & notes

Covers **lines, arcs/circles/ellipses, points, text, block definitions + inserts, and dimensions**. Block definitions become DXF `BLOCK`s and inserts become `INSERT`s (`Drawing.blocks` holds the defs by number); dimensions are decomposed into their drawn parts (dimension line, value text, witness lines, arrows). **Text is decoded to Unicode at read time** (`Entity.text.string`) from the file's CP932 (Shift-JIS) bytes via `JWW.decodeCP932`, and the DXF writer emits non-ASCII as `\U+XXXX` escapes so Japanese renders in AutoCAD / LibreCAD regardless of code page. (CP932 decoding uses CoreFoundation — reliable on Apple platforms; on Linux it falls back and Japanese may not decode, but geometry still converts.)

> Block/dimension support is validated on synthetic fixtures and is structurally correct against the > documented format; the line/arc/point/text core is additionally validated byte-for-byte against the > reference reader on real drawings.

DWG output is out of scope (proprietary); produce DXF here and convert to DWG downstream (e.g. the free ODA File Converter) if needed.

## License

MIT. JWW and Jw_cad are the work of their respective authors; the reference `jwwlib` is part of LibreCAD (GPL). This is a clean-room reimplementation of the format — no jwwlib code is included.

## Package Metadata

Repository: secondmouseau/swiftjww

Default branch: main

README: README.md