# Source: math/Color.js

``````/**
*  @class Color
*  @memberof SQR
*
*  @descrption represents an RGB color. This class works with float values,
*	so all the color components are in range of 0-1, not 0-255.
*
*	@param {Number=} r the red component of the color
*	@param {Number=} g the green component of the color
*	@param {Number=} b the blue component of the color
*	@param {Number=} a the transparency (alpha) component of the color
*
*/
SQR.Color = function(r, g, b, a) {
if(!(this instanceof SQR.Color)) return new SQR.Color(r, g, b, a);

if(typeof(r) == 'string') {
this.setHex(r);
this.a = (g == undefined) ? 1 : g; // if r is a hex color code, the next argument will be alpha
} else if(r && r.r != undefined) {
this.setRGB(r.r, r.g, r.b);

if(r.a != undefined) this.a = r.a;
else if(g != undefined) this.a = g;
else this.a = 1;

} else {
this.setRGB(r, g, b);
this.a = (a == undefined) ? 1 : a;
}
}

/**
*	@method setRGB
*	@memberof SQR.Color.prototype
*
*	@description sets the color component values.
*
*	@param {Number=} r the red component of the color
*	@param {Number=} g the green component of the color
*	@param {Number=} b the blue component of the color
*
*	@returns {Object} reference to this SQR.Color instance, for chaining
*/
SQR.Color.prototype.setRGB = function(r, g, b, a) {
var c = this;
c.r = r || 0;
c.g = g || 0;
c.b = b || 0;
c.a = a != null ? a : 1;
return c;
}

/**
*	@method setHex
*	@memberof SQR.Color.prototype
*
*	@description sets the color component values from a hex string (ex. #a4d278) or number (ex. 0xa4d278)
*	Useful when copying color vaues from ex. Photoshop.
*
*	@param {string|Number} hex the hex color values as string (ex. #a4d278) or number (ex. 0xa4d278)
*
*	@returns {Object} reference to this SQR.Color instance, for chaining
*/
SQR.Color.prototype.setHex = function(hex) {

var c = this;

if(typeof(hex) == 'string') {
hex = (hex.indexOf('#') == 0) ? hex.substring(1) : hex;
hex = (hex.indexOf('0x') == -1) ? '0x' + hex : hex;
hex = parseInt(hex);
}

c.r = (hex >> 16 & 255 ) / 255;
c.g = (hex >> 8 & 255) / 255;
c.b = (hex & 255) / 255;
c.a = 1;

return c;
}

SQR.Color.prototype.setCSS = function(css) {

var c = this;

if(css.indexOf("#") > -1) {
this.setHex(css);
} else {
var v = css.match(/\(([^\)]+)\)/);
v = v[1].split(",");

c.r = parseInt(v[0]) / 255;
c.g = parseInt(v[1]) / 255;
c.b = parseInt(v[2]) / 255;

var a = css.indexOf("a") > -1;
if(a) c.a = parseFloat(v[3]);
else c.a = 1;
}

return c;
}

/**
*	@method toCSS
*	@memberof SQR.Color.prototype
*
*	@returns {string} a CSS friendly string representing the color. The format used is <code>rgb(r, g, b)</code>.
*/
SQR.Color.prototype.toCSS = function() {
var c = this;
var ri = (c.r * 255) | 0;
var gi = (c.g * 255) | 0;
var bi = (c.b * 255) | 0;
var ai = (c.a < 1) ? ', ' + c.a.toPrecision(2) : '';
var h =  (c.a < 1) ? 'rgba' : 'rgb';
return h + '(' + ri + ', ' + gi + ', ' + bi + '' + ai + ')';
}

SQR.Color.prototype.toHex = function() {

var c = this;

var c2h = function(c) {
var hex = Math.round(c * 255).toString(16);
return hex.length == 1 ? "0" + hex : hex;
}

return "#" + c2h(c.r) + c2h(c.g) + c2h(c.b);
}

/**
*	@method setRGB
*	@memberof SQR.Color.prototype
*
*	@description copies the color component values from another instance of SQR.Color
*
*	@param {SQR.Color} oc the color instance to copy from
*
*	@returns {Object} reference to this SQR.Color instance, for chaining
*/
SQR.Color.prototype.copyFrom = function(oc) {
var c = this;
c.r = oc.r;
c.g = oc.g;
c.b = oc.b;
return c;
}

/**
*	@method lighten
*	@memberof SQR.Color.prototype
*
*	@description <p>modfies the color values to make them darker of lighter in a more fance way than a simple multiplication.
*	However this is not currently implemented so for now it really does the same thing as <code>SQR.Color.mul</code>.</p>
*
*	<p>Here's <a href='http://stackoverflow.com/questions/141855/programmatically-lighten-a-color'>some info on how to implement this properly</a>.</p>
*/
SQR.Color.prototype.lighten = function(v) {
return this.mul(v);
}

/**
*	@method clone
*	@memberof SQR.Color.prototype
*
*	@description creates a copy of the color instance
*
*	@returns {Object} a new SQR.Color instance
*/
SQR.Color.prototype.clone = function() {
return new SQR.Color(c.r, c.g, c.b);
}

/**
*	@method mul
*	@memberof SQR.Color.prototype
*
*	@description modfies the color values to make it darker of lighter
*
*	@param {Number} v the amount by which to change the color (1 will leave it as it, > 1 will lightned, < 1 will darken the color)
*
*	@returns {Object} reference to this SQR.Color instance, for chaining
*/
SQR.Color.prototype.mul = function(v) {
var c = this;
c.r = Math.min(1.0, c.r * v);
c.g = Math.min(1.0, c.g * v);
c.b = Math.min(1.0, c.b * v);
return c;
}

/**
*	@method lerp
*	@memberof SQR.Color.prototype
*
*	@description performs a linear interpolation between two colors and stores the value in the color instance
*
*	@param {SQR.Color} a the first color to use in interpolation
*	@param {SQR.Color} b the second color to use in interpolation
*	@param {Number} t the interpolation value [0-1]
*
*	@returns {Object} reference to this SQR.Color instance, for chaining
*/
SQR.Color.prototype.lerp  = function(a, b, t) {
var c = this;
var m = 1 - t;
c.r = a.r * m + b.r * t;
c.g = a.g * m + b.g * t;
c.b = a.b * m + b.b * t;
return c;
}

SQR.Color.prototype.toUniform = function(type) {

var alpha = type == SQR.gl.FLOAT_VEC4;

var c = this;
if(!c._array) c._array = new Float32Array(alpha ? 4 : 3);
c._array[0] = c.r;
c._array[1] = c.g;
c._array[2] = c.b;
if(alpha) c._array[3] = c.a;
return c._array;
}

``````