@amaui/utils/quantize.js

Utils

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const colorRange = (value) => {
    const min = new Array(3).fill(Number.MAX_VALUE);
    const max = new Array(3).fill(Number.MIN_VALUE);
    value.forEach(item => {
        item.forEach((value_, index) => {
            min[index] = Math.min(min[index], value_);
            max[index] = Math.max(max[index], value_);
        });
    });
    const ranges = min.map((item, index) => max[index] - item);
    const maxRange = Math.max(...ranges);
    if (maxRange === ranges[0])
        return 0;
    else if (maxRange === ranges[1])
        return 1;
    return 2;
};
const quantizeMethod = (value, depth = 0) => {
    const MAX_DEPTH = 7;
    if (!value.length)
        return [];
    if (MAX_DEPTH === depth) {
        const color = value.reduce((result, item) => {
            item.forEach((value_, index) => result[index] += value_);
            return result;
        }, [0, 0, 0]);
        return [color.map(item => Math.round(item / value.length))];
    }
    const sortIndex = colorRange(value);
    value.sort((a, b) => a[sortIndex] - b[sortIndex]);
    const mid = value.length / 2;
    // Reverse so primary is a first value
    return [
        ...quantizeMethod(value.slice(0, mid), depth + 1),
        ...quantizeMethod(value.slice(mid + 1), depth + 1),
    ].reverse();
};
const quantize = (value, amount = 4) => {
    const depth = 7 - Math.ceil(Math.log2(amount));
    return quantizeMethod(value, depth).slice(0, amount);
};
exports.default = quantize;