scale-color-perceptual

scale-color-perceptual
========================

> Javascript exports of matplotlib's new default color scales; inferno, magma, plasma and viridis. Works with browserify and D3.js

!Image showing inferno, magma, plasma and viridis respectively
Inferno, magma, plasma and viridis respectively
Installation
------------

``bash
npm install scale-color-perceptual
`

Usage
-----

`js
const scale = require('scale-color-perceptual')

[0, 0.25, 0.5, 0.75, 1].map(scale.viridis) // Spits out the colors at the given points
`

Exports scale.inferno(t), scale.magma(t), scale.plasma(t) and
scale.viridis(t), all taking scale parameter t in the range [0, 1].
If a number is given outside this range is given an Error will be thrown.

Each of the scales has been put in the root of the module allowing you
to import only the scale you need, yielding a smaller JS file:

`js

const viridis = require('scale-color-perceptual/viridis')

[0, 0.25, 0.5, 0.75, 1].map(viridis) // Spits out the colors at the given
`

It can also be used with D3:

`js
const d3 = require('d3')
const plasma = require('scale-color-perceptual/plasma')

const depthScale = d3.scale.linear().domain([-100, 100]) // default range is [0, 1]
.clamp(true) // Make sure the output is constrained to [0, 1]

d3.selectAll('div', document.body)
.data(d3.shuffle(d3.range(-100, 100, 0.1)).map(n => Math.random() * n))
.enter().append('div')
.style({
background: d => viridis(depthScale(d)),
width: '10px',
height: '10px',
float: 'left'
})
`

You can also import the raw color maps, either as hex or rgb triplets ([r, g, b], where c is in [0, 1]):

`js
const d3 = require('d3')
const plasmaMap = require('scale-color-perceptual/hex/plasma') // returns 256 hex colors from dark to bright

const colorScale = d3.scale.quantize().domain([-128, 127]).range(plasmaMap)
`

Development
-----------

rgb/ contains raw JSON exports of the pixel [r, g, b] triplets
from [bids/colormap][1], which are the default color scales in matplotlib 2.0.
The pixel triplets were obtained from [bids/colormap#84cb377][2]. To build the
corresponding hex/ files, run make`.

License
-------

All credits go to Stéfan van der Walt and Nathaniel Smith for their work
devising these color scales. Remember to watch their [talk][1] on how it was
derived and how it is better than other common scales

The code in this repository is licensed under ISC

[1]: http://bids.github.io/colormap/
[2]: https://github.com/BIDS/colormap/blob/84cb3771a38dfe3d3977677df31af55f4ab7985e/colormaps.py