swift-displaywidth

A portable/cross-platform implementation of wcwidth(3) with up-to-date Unicode spec. This project has own Unicode data tables generated from following files.

• https://unicode.org/Public/17.0.0/ucd/UnicodeData.txt
• https://unicode.org/Public/17.0.0/ucd/EastAsianWidth.txt

Why use this?

Instead of this library, there's wcwidth imported with import Darwin, import Musl, or import Glibc.

• https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/wcwidth.3.html
• https://www.gnu.org/software/gnulib/manual/html_node/wcwidth.html
• https://git.musl-libc.org/cgit/musl/tree/src/ctype/wcwidth.c

If that meets your requirements, you should just use it. However, this project has following superior points.

• Portable/Cross-platform implementation that doesn't require a C library nor even Foundation
• Up-to-date Unicode spec
• Better support of Unicode grapheme clusters
• Swift-friendly API

Usage

Add to your Package.swift:

dependencies: [
    .package(url: "https://github.com/ainame/swift-displaywidth", from: "0.0.3")
]

Then:

import DisplayWidth

// call as function
let displayWidth = DisplayWidth()
displayWidth("A")        // 1
displayWidth("あ")       // 2
displayWidth("👩‍💻")       // 2
displayWidth("e\u{0301}") // 1 (e + combining acute)

// If your environment treat ambiguous chars as full-width,
// you can set this option.
let displayWidth = DisplayWidth(treatAmbiguousAsFullWidth: true)

Links

• https://man7.org/linux/man-pages/man3/wcwidth.3.html
• Other langs
  • Python https://github.com/jquast/wcwidth
  • Go https://github.com/mattn/go-runewidth/
  • JS https://github.com/komagata/eastasianwidth/
• https://emonkak.pages.dev/articles/wcwidth/
  • This project (to avoid using wcwidth(3)) is against to this blog post but I took ideas around full-width symbols