big-moving.ru/api/soft/picozu/histogram.js.1

/**
 * Part of Picozu Image Editing application.
 * Visit https://www.picozu.com for more info.
 * The code is copyrighted by Picozu <www.picozu.com>.
 * 
 * @version 1.1.121413
 * @package Workers
 * @application Picozu <www.picozu.com>
 * @license www.picozu.com/license
 */

self.addEventListener('message', function (e) {
    function process(data) {
        data.type = (typeof data.type != 'undefined') ? data.type : 'rgb';
        return {
            histogram: calculate(data.type, data.imageData.data),
            type: data.type
        }
    }
    self.postMessage(process(e.data));
}, false);

function calculate(type, imgData) {
    var chans = [[]];
    var maxCount = 0;
    var val;
    var subtypes = [type];
    if (type === 'rgb') {
        chans = [
            [],
            [],
            []
        ];
        subtypes = [
            'red',
            'green',
            'blue'
        ];
    }
    else if (type === 'cmyk') {
        chans = [
            [],
            [],
            [],
            []
        ];
        subtypes = [
            'cyan',
            'magenta',
            'yellow',
            'kelvin'
        ];
    }
    var step = 4;
    for (var i = 0, n = imgData.length; i < n; i += step) {
        if (type === 'rgb' || type === 'red' || type === 'green' || type === 'blue') {
            val = [imgData[i], imgData[i + 1], imgData[i + 2]];
        }
        else if (type === 'cmyk' || type === 'cyan' || type === 'magenta' || type === 'yellow' || type === 'kelvin') {
            val = rgb2cmyk(imgData[i], imgData[i + 1], imgData[i + 2]);
        }
        else if (type === 'hue' || type === 'sat' || type === 'val') {
            val = rgb2hsv(imgData[i], imgData[i + 1], imgData[i + 2]);
        }
        if (type === 'red' || type === 'hue' || type === 'cyan') {
            val = [val[0]];
        }
        else if (type === 'green' || type === 'sat' || type === 'magenta') {
            val = [val[1]];
        }
        else if (type === 'blue' || type === 'val' || type === 'yellow') {
            val = [val[2]];
        }
        else if (type === 'kelvin') {
            val = [val[3]];
        }
        for (var y = 0, m = val.length; y < m; y++) {
            if (val[y] in chans[y]) {
                chans[y][val[y]]++;
            }
            else {
                chans[y][val[y]] = 1;
            }
            if (chans[y][val[y]] > maxCount) {
                maxCount = chans[y][val[y]];
            }
        }
    }
    if (maxCount === 0) {
        return null;
    }
    else {
        return {
            subtypes: subtypes,
            chans: chans,
            maxCount: maxCount
        }
    }
}

function rgb2hsv(red, green, blue) {
    red /= 255;
    green /= 255;
    blue /= 255;
    var hue, sat, val, min = Math.min(red, green, blue), max = Math.max(red, green, blue), delta = max - min, val = max;
    if (delta === 0) {
        hue = sat = 0;
    }
    else {
        sat = delta / max;
        if (max === red) {
            hue = (green - blue) / delta;
        }
        else if (max === green) {
            hue = (blue - red) / delta + 2;
        }
        else if (max === blue) {
            hue = (red - green) / delta + 4;
        }
        hue /= 6;
        if (hue < 0) {
            hue += 1;
        }
    }
    return [
        Math.round(hue * 255),
        Math.round(sat * 255),
        Math.round(val * 255)
    ];
}

function rgb2cmyk(red, green, blue) {
    var cyan = 1 - red / 255;
    var magenta = 1 - green / 255;
    var yellow = 1 - blue / 255;
    var black = Math.min(cyan, magenta, yellow, 1);
    if (black === 1) {
        cyan = magenta = yellow = 0;
    }
    else {
        var w = 1 - black;
        cyan = (cyan - black) / w;
        magenta = (magenta - black) / w;
        yellow = (yellow - black) / w;
    }
    return [
        Math.round(cyan * 255),
        Math.round(magenta * 255),
        Math.round(yellow * 255),
        Math.round(black * 255)
    ];
}