jquery.angle.js

///////////////////////////////////////////////////////
// Angle
///////////////////////////////////////////////////////
(function($, window, document, undefined) {
	/**
	 * Converting a radian to a degree
	 * @const
	 */
	var RAD_DEG = 180/Math.PI;
	
	/**
	 * Converting a radian to a grad
	 * @const
	 */
	var RAD_GRAD = 200/Math.PI;
	
	/**
	 * Converting a degree to a radian
	 * @const
	 */
	var DEG_RAD = Math.PI/180;
	
	/**
	 * Converting a degree to a grad
	 * @const
	 */
	var DEG_GRAD = 2/1.8;
	
	/**
	 * Converting a grad to a degree
	 * @const
	 */
	var GRAD_DEG = 0.9;
	
	/**
	 * Converting a grad to a radian
	 * @const
	 */
	var GRAD_RAD = Math.PI/200;
	
	
	var rfxnum = /^([+\-]=)?([\d+.\-]+)(.*)$/;
	
	/**
	 * Functions for converting angles
	 * @var Object
	 */
	$.extend({
		angle: {
			/**
			 * available units for an angle
			 * @var Regex
			 */
			runit: /(deg|g?rad)/,
			
			/**
			 * Convert a radian into a degree
			 * @param Number rad
			 * @return Number
			 */
			radianToDegree: function(rad) {
				return rad * RAD_DEG;
			},
			
			/**
			 * Convert a radian into a degree
			 * @param Number rad
			 * @return Number
			 */
			radianToGrad: function(rad) {
				return rad * RAD_GRAD;
			},
			
			/**
			 * Convert a degree into a radian
			 * @param Number deg
			 * @return Number
			 */
			degreeToRadian: function(deg) {
				return deg * DEG_RAD;
			},
			
			/**
			 * Convert a degree into a radian
			 * @param Number deg
			 * @return Number
			 */
			degreeToGrad: function(deg) {
				return deg * DEG_GRAD;
			},
			
			/**
			 * Convert a grad into a degree
			 * @param Number grad
			 * @return Number
			 */
			gradToDegree: function(grad) {
				return grad * GRAD_DEG;
			},
			
			/**
			 * Convert a grad into a radian
			 * @param Number grad
			 * @return Number
			 */
			gradToRadian: function(grad) {
				return grad * GRAD_RAD;
			},
			
			/**
			 * Convert an angle with a unit to a degree
			 * @param String val angle with a unit
			 * @return Number
			 */
			toDegree: function (val) {
				var parts = rfxnum.exec(val);
				if (parts) {
					val = parseFloat( parts[2] );
					switch (parts[3] || 'deg') {
						case 'grad':
							val = $.angle.gradToDegree(val);
							break;
						case 'rad':
							val = $.angle.radianToDegree(val);
							break;
					}
					return val;
				}
				return 0;
			}
		}
	});
})(jQuery, this, this.document);