File: color/js/color-hsv.js

/**
Color provides static methods for color conversion hsv values.

    Y.Color.toHSV('f00'); // hsv(0, 100%, 100%)

    Y.Color.toHSVA('rgb(255, 255, 0'); // hsva(60, 100%, 100%, 1)


@module color
@submodule color-hsv
@class HSV
@namespace Color
@since 3.8.0
**/
Color = {

    /**
    @static
    @property REGEX_HSV
    @type RegExp
    @default /hsva?\(([.\d]*), ?([.\d]*)%, ?([.\d]*)%,? ?([.\d]*)?\)/
    @since 3.8.0
    **/
    REGEX_HSV: /hsva?\(([.\d]*), ?([.\d]*)%, ?([.\d]*)%,? ?([.\d]*)?\)/,

    /**
    @static
    @property STR_HSV
    @type String
    @default hsv({*}, {*}%, {*}%)
    @since 3.8.0
    **/
    STR_HSV: 'hsv({*}, {*}%, {*}%)',

    /**
    @static
    @property STR_HSVA
    @type String
    @default hsva({*}, {*}%, {*}%, {*})
    @since 3.8.0
    **/
    STR_HSVA: 'hsva({*}, {*}%, {*}%, {*})',

    /**
    Converts provided color value to an HSV string.
    @public
    @method toHSV
    @param {String} str
    @return {String}
    @since 3.8.0
    **/
    toHSV: function (str) {
        var clr = Y.Color._convertTo(str, 'hsv');
        return clr.toLowerCase();
    },

    /**
    Converts provided color value to an HSVA string.
    @public
    @method toHSVA
    @param {String} str
    @return {String}
    @since 3.8.0
    **/
    toHSVA: function (str) {
        var clr = Y.Color._convertTo(str, 'hsva');
        return clr.toLowerCase();
    },

    /**
    Parses the RGB string into h, s, v values. Will return an Array
        of values or an HSV string.
    @protected
    @method _rgbToHsv
    @param {String} str
    @param {Boolean} [toArray]
    @return {String|Array}
    @since 3.8.0
    **/
    _rgbToHsv: function (str, toArray) {
        var h, s, v,
            rgb = Y.Color.REGEX_RGB.exec(str),
            r = rgb[1] / 255,
            g = rgb[2] / 255,
            b = rgb[3] / 255,
            max = Math.max(r, g, b),
            min = Math.min(r, g, b),
            delta = max - min;

        if (max === min) {
            h = 0;
        } else if (max === r) {
            h = 60 * (g - b) / delta;
        } else if (max === g) {
            h = (60 * (b - r) / delta) + 120;
        } else { // max === b
            h = (60 * (r - g) / delta) + 240;
        }

        s = (max === 0) ? 0 : 1 - (min / max);

        // ensure h is between 0 and 360
        while (h < 0) {
            h += 360;
        }
        h %= 360;
        h = Math.round(h);

        // saturation is percentage
        s = Math.round(s * 100);

        // value is percentage
        v = Math.round(max * 100);

        if (toArray) {
            return [h, s, v];
        }

        return Y.Color.fromArray([h, s, v], Y.Color.TYPES.HSV);
    },

    /**
    Parses the HSV string into r, b, g values. Will return an Array
        of values or an RGB string.
    @protected
    @method _hsvToRgb
    @param {String} str
    @param {Boolean} [toArray]
    @return {String|Array}
    @since 3.8.0
    **/
    _hsvToRgb: function (str, toArray) {
        var hsv = Y.Color.REGEX_HSV.exec(str),
            h = parseInt(hsv[1], 10),
            s = parseInt(hsv[2], 10) / 100, // 0 - 1
            v = parseInt(hsv[3], 10) / 100, // 0 - 1
            r,
            g,
            b,
            i = Math.floor(h / 60) % 6,
            f = (h / 60) - i,
            p = v * (1 - s),
            q = v * (1 - (s * f)),
            t = v * (1 - (s * (1 - f)));

        if (s === 0) {
            r = v;
            g = v;
            b = v;
        } else {
            switch (i) {
                case 0: r = v; g = t; b = p; break;
                case 1: r = q; g = v; b = p; break;
                case 2: r = p; g = v; b = t; break;
                case 3: r = p; g = q; b = v; break;
                case 4: r = t; g = p; b = v; break;
                case 5: r = v; g = p; b = q; break;
            }
        }

        r = Math.min(255, Math.round(r * 256));
        g = Math.min(255, Math.round(g * 256));
        b = Math.min(255, Math.round(b * 256));

        if (toArray) {
            return [r, g, b];
        }

        return Y.Color.fromArray([r, g, b], Y.Color.TYPES.RGB);
    }

};

Y.Color = Y.mix(Color, Y.Color);

Y.Color.TYPES = Y.mix(Y.Color.TYPES, {'HSV':'hsv', 'HSVA':'hsva'});
Y.Color.CONVERTS = Y.mix(Y.Color.CONVERTS, {'hsv': 'toHSV', 'hsva': 'toHSVA'});