README.md

polylinear-scale

Create piecewise linear scales à la d3:

Although continuous scales typically have two values each in their domain and range, specifying more than two values produces a piecewise scale.

• Supports domains and ranges with more than two values each.
• Supports clamping to range.
• No dependencies.

For many more features, see d3-scale.

For an even simpler version that does not support multiple piecewise scales, see simple-linear-scale.

Setup

As a Node.js module:

$ yarn add polylinear-scale

# or

$ npm install polylinear-scale

CDN version:

<!-- Minified -->
<script src="https://unpkg.com/polylinear-scale/dist/polylinear-scale.min.js"></script>

<!-- Un-minified -->
<script src="https://unpkg.com/polylinear-scale/dist/polylinear-scale.js"></script>

Arguments

• domain (Array): The input domain (default is [0, 1]).
• range (Array): The output range (default is [0, 1]).
• clamp (Boolean): Enable or disable clamping (default is false).

Returns

• (Function): The resulting scaling function.

Examples

const polylinearScale = require('polylinear-scale')

// Create a linear scale
const linear = polylinearScale([0, 1], [0, 100])
console.log(linear(0.5)) // 50

// Create a polylinear scale
const polylinear = polylinearScale([0, 100, 300], [0, 50, 100])
console.log(polylinear(10)) // 5
console.log(polylinear(-10)) // -5

// Clamp results to the given range
const clamped = polylinearScale([-10, 0, 10], [-5, 2, 10], true)
console.log(clamped(11)) // 10

Contributing

Uses JavaScript Standard Style.

# test
$ npm run test