accent-color-getter

This is a very simple Node.js native module for use on Windows that gets the user's selected accent color and the three light and three dark variations of the color.

This was conceived for use in Electron apps because (at least currently), the built-in systemPreferences API only lets you get the system color and not the variations. (Note that the accent-color-changed) event does work and is useful along with this.)

After a little digging, it seems that calculating the variations is non-trivial[^1], so just retrieving them from the OS is the best way to match what other apps would be doing.

Use

Generally use the getSystem() function to get the current system accent colors. This returns an object with keys AccentDark3, AccentDark2, etc. Each of these is an object with the R, G, B, A values and some strings for use in CSS directly.

There are also a few preset groups which may be useful for testing and development.

const AccentColorGetter = require('accent-color-getter');
const getter = new AccentColorGetter();
const systemAccentColors = getter().getSystem();
const navyBlueAccents = getter.presets.navyBlue;

Returned objects look like:

{
  // ...

  AccentDark2: {
    id: 3,
    R: 131,
    G: 0,
    B: 72,
    A: 255,
    hexRGB: '#830048',
    hexRGBA: '#830048ff',
    rgba: 'rgba(131, 0, 72, 1.0)'
  },

  // ...
}

Development

This was bootstrapped with the handy napi-module Yeoman generator. Then the code simply makes appropriate calls to UISettings.GetColorValue and packages the results.

On macOS, this will install but will simply throw an exception that the consuming application will need to handle.

[^1]: Non-trivial (and undocumented) for precise calculation, but in broad strokes, you convert the base RGB value to HSV and then as you go lighter, the hue stays roughly constant, the saturation decreases quickly, and the value increases relatively slowly; and as you go darker, the hue and saturation stay roughly constant, and the value decreases.