c0lor/hsv.js

Color space conversions

var O, createHsv, floor, hsv, hsvPrototype;

O = require("ut1l/create/object");

floor = Math.floor;

hsvPrototype = {
  rgb: function(T) {
    var f, h, p, q, t;
    if (T == null) {
      T = require("./rgb")();
    }
    if (this.s === 0) {
      return T.set(this.v, this.v, this.v);
    } else {
      h = (this.h - floor(this.h)) * 6;
      f = h - floor(h);
      p = this.v * (1 - this.s);
      q = this.v * (1 - this.s * f);
      t = this.v * (1 - this.s * (1 - f));
      switch (floor(h)) {
        case 0:
          return T.set(this.v, t, p);
        case 1:
          return T.set(q, this.v, p);
        case 2:
          return T.set(p, this.v, t);
        case 3:
          return T.set(p, q, this.v);
        case 4:
          return T.set(t, p, this.v);
        case 5:
          return T.set(this.v, p, q);
      }
    }
  },
  set: function(h1, s, v) {
    this.h = h1;
    this.s = s;
    this.v = v;
    return this;
  },
  toString: function() {
    return "h=" + this.h + ", s=" + this.s + ", v=" + this.v;
  }
};

hsv = createHsv = O((function(h1, s, v) {
  this.h = h1;
  this.s = s;
  this.v = v;
}), hsvPrototype);

(require("./rgb")).extendRgb(function(rgb) {
  return rgb.hsv = function(T) {
    var d, max, min;
    if (T == null) {
      T = createHsv();
    }
    max = Math.max(this.r, this.g, this.b);
    min = Math.min(this.r, this.g, this.b);
    T.v = max;
    d = max - min;
    T.s = max !== 0 ? d / max : 0;
    if (T.s === 0) {
      T.h = 0;
    } else {
      switch (max) {
        case this.r:
          T.h = this.g < this.b ? 6 : 0;
          T.h += (this.g - this.b) / d;
          break;
        case this.g:
          T.h = 2 + (this.b - this.r) / d;
          break;
        default:
          T.h = 4 + (this.r - this.g) / d;
      }
      T.h /= 6;
    }
    return T;
  };
});

module.exports = hsv;