1#!/usr/bin/env swift
2// A script to set the accent colour of your Mac.
3//
4// This mimics the accent colour picker in the General pane of
5// System Preferences, and should cause all apps to pick up the change.
6//
7// Usage: pass the colour you want to use as a single command-line argument,
8// e.g.
9//
10//      $ set_accent_colour red
11//      $ set_accent_colour green
12//
13// Tested on macOS Monterey.
14//
15// You may need to run `chmod +x set_accent_colour` first and install the Xcode
16// command-line tools.
17//
18// == How it works ==
19//
20// You can set the accent colour using a `defaults write` command,
21// e.g. to change your accent colour to pink:
22//
23//      $ defaults write -globalDomain AppleAccentColor -int 6
24//
25// But this doesn't take effect immediately -- we have to send notifications
26// AppleColorPreferencesChangedNotification and
27// AppleAquaColorVariantChanged to tell apps they should update their UIs.
28//
29// == Attribution ==
30//
31// Based on code/ideas by Henrik Helmers, Garth Mortensen, and Robert Sesek.
32//
33// See https://alexwlchan.net/2022/11/changing-the-macos-accent-colour/
34
35import Foundation
36
37// A map of colour names to the int values in AppleAccentColor.
38//
39// I created this map by selected all the accent colours in System Preferences,
40// then running `defaults read -globalDomain AppleAccentColor` and recording
41// the result.
42let colourMap = [
43  ("red",       0),
44  ("orange",    1),
45  ("yellow",    2),
46  ("green",     3),
47  ("blue",      4),
48  ("purple",    5),
49  ("pink",      6),
50  ("graphite", -1),
51]
52
53// Read the selected colour from the command-line arguments.
54func getSelectedColour() -> String {
55  let arguments = CommandLine.arguments
56
57  let colourNames = colourMap.map { $0.0 }
58
59  // If the user hasn't supplied a colour, of they've selected an invalid
60  // colour, print a helpful help message. e.g.
61  //
62  //    $ set_accent_colour blurple
63  //    Usage: set_accent_colour <red|orange|yellow|green|blue|purple|pink|graphite>
64  //
65  if arguments.count != 2 || !colourNames.contains(arguments[1]) {
66    let colours = colourNames.joined(separator:"|")
67    fputs("Usage: \(arguments[0]) <\(colours)>\n", stderr)
68    exit(1)
69  }
70
71  return arguments[1]
72}
73
74func setAccentColour(colour: String) -> () {
75  let colourDict = Dictionary(uniqueKeysWithValues: colourMap)
76  let accentValue: Int = colourDict[colour]!
77
78  // This is the equivalent of
79  //
80  //    $ defaults write -globalDomain AppleAccentColor -int <prefValue>
81  //
82  UserDefaults.standard.setPersistentDomain(
83    ["AppleAccentColor": Optional(accentValue) as Any],
84    forName: UserDefaults.globalDomain
85  )
86
87  let notifications = [
88    "AppleColorPreferencesChangedNotification",
89    "AppleAquaColorVariantChanged"
90  ]
91
92  for name in notifications {
93    let notifyEvent = Notification.Name(name)
94    DistributedNotificationCenter.default().post(name: notifyEvent, object: nil)
95  }
96}
97
98let colour = getSelectedColour()
99setAccentColour(colour: colour)