@legumeinfo/taxon-symbology/lib/index.js

A TypeScript library for consistent coloring of visualizations by genus & species

/*
 * use the chroma.js library to colorize taxons consistently and predictably.
 * e.g. Always returns same hue for Arachis, but scaled lightness depending on
 * the Species -- completely abitrarily, but consistently.
 *
 * taxonChroma.get(taxon, options);
 *
 * // examples:
 * taxonChroma.get('Arachis hypogaea');
 * taxonChroma.get('Arachis burkartii');
 *
 * // make 20% lighter overall
 * taxonChroma.get(someTaxon, { lightnessFactor: 1.2 } );
 *
 * // override some taxon
 * taxonChroma.get(acc.properties.taxon, {
 *  'lightnessFactor' : 1.2,
 *  'overrides' : {
 *   'phaseolus lunatus' : 'green',
 *  }
 * });
 */
import * as chroma from 'chroma.ts';
// New colors 15 degrees apart in hue space, to reduce conflicts
const baseColors = {
    acacia: '#ffc000',
    aeschynomene: '#ff4000',
    apios: '#00c0ff',
    arachis: '#ff8000',
    bauhinia: '#ff00c0',
    cajanus: '#0040ff',
    cercis: '#ff0040',
    chamaecrista: '#ffff00',
    cicer: '#80ff00',
    dalbergia: '#ff0000',
    glycine: '#4000ff',
    lablab: '#8000ff',
    lens: '#00ff80',
    lotus: '#00ffff',
    lupinus: '#c000ff',
    medicago: '#40ff00',
    phanera: '#ff0080',
    phaseolus: '#0000ff',
    pisum: '#00ff00',
    quillaja: '#666666', // not a legume, but related
    senna: '#c0ff00',
    sindora: '#ff00ff',
    trifolium: '#00ff40',
    vicia: '#00ffc0',
    vigna: '#0080ff',
};
export const genera = Object.keys(baseColors);
/**
 * a consistent hashing algorithm
 * https://gist.github.com/vaiorabbit/5657561
 * http://isthe.com/chongo/tech/comp/fnv/#xor-fold
 **/
function fnv32a(str, hashSize) {
    const FNV1_32A_INIT = 0x811c9dc5;
    let hval = FNV1_32A_INIT;
    for (let i = 0; i < str.length; ++i) {
        hval ^= str.charCodeAt(i);
        hval +=
            (hval << 1) + (hval << 4) + (hval << 7) + (hval << 8) + (hval << 24);
    }
    return (hval >>> 0) % hashSize;
}
export class TaxonChroma {
    constructor(defaultColor = '#d3d3d3') {
        this.colorCache = {};
        this.defaultColor = defaultColor;
    }
    get(taxon, options = {}) {
        if (taxon.indexOf(' ') === -1) {
            throw 'Error: required format is "genus species" with a space between';
        }
        taxon = taxon.toLowerCase();
        // options is an object w/ keys lightnessFactor, overrides
        const { lightnessFactor = TaxonChroma.LIGHTNESS_FACTOR, overrides = {} } = options;
        // convert overrides to lowercase
        const lowerOverrides = Object.fromEntries(Object.entries(overrides).map(([k, v]) => [k.toLowerCase(), v]));
        // return override color
        if (lowerOverrides[taxon] !== undefined) {
            return lowerOverrides[taxon];
        }
        // return cached color
        if (this.colorCache[taxon] !== undefined) {
            return this.colorCache[taxon];
        }
        // compute color
        let color = this.defaultColor;
        const [genus, species, ..._] = taxon.split(' ');
        if (genus in baseColors) {
            const genusColor = baseColors[genus];
            const [hue, ..._] = chroma.color(genusColor).hsl();
            const lightness = TaxonChroma.MIN_LIGHTNESS +
                (fnv32a(species, 1000) / 1000) * (1 - 2 * TaxonChroma.MIN_LIGHTNESS);
            color = chroma.color(hue, 1, lightness * lightnessFactor, 'hsl').hex();
        }
        this.colorCache[taxon] = color;
        return color;
    }
}
// default lightness factor (1= don't post-adjust)
TaxonChroma.LIGHTNESS_FACTOR = 1;
TaxonChroma.MIN_LIGHTNESS = 0.3;
export const taxonChroma = new TaxonChroma();
//# sourceMappingURL=index.js.map