/*eslint-disable  eqeqeq, no-cond-assign, no-empty*/
(function() {
    'use strict';
    /**
     * Collection constructor.  Collection extends
     *  Array.  This class is used in conjunction with {@link Konva.Container#get}
     * @constructor
     * @memberof Konva
     */
    Konva.Collection = function() {
        var args = [].slice.call(arguments), length = args.length, i = 0;

        this.length = length;
        for(; i < length; i++) {
            this[i] = args[i];
        }
        return this;
    };
    Konva.Collection.prototype = [];
    /**
     * iterate through node array and run a function for each node.
     *  The node and index is passed into the function
     * @method
     * @memberof Konva.Collection.prototype
     * @param {Function} func
     * @example
     * // get all nodes with name foo inside layer, and set x to 10 for each
     * layer.get('.foo').each(function(shape, n) {
     *   shape.setX(10);
     * });
     */
    Konva.Collection.prototype.each = function(func) {
        for(var n = 0; n < this.length; n++) {
            func(this[n], n);
        }
    };
    /**
     * convert collection into an array
     * @method
     * @memberof Konva.Collection.prototype
     */
    Konva.Collection.prototype.toArray = function() {
        var arr = [],
            len = this.length,
            n;

        for(n = 0; n < len; n++) {
            arr.push(this[n]);
        }
        return arr;
    };
    /**
     * convert array into a collection
     * @method
     * @memberof Konva.Collection
     * @param {Array} arr
     */
    Konva.Collection.toCollection = function(arr) {
        var collection = new Konva.Collection(),
            len = arr.length,
            n;

        for(n = 0; n < len; n++) {
            collection.push(arr[n]);
        }
        return collection;
    };

    // map one method by it's name
    Konva.Collection._mapMethod = function(methodName) {
        Konva.Collection.prototype[methodName] = function() {
            var len = this.length,
                i;

            var args = [].slice.call(arguments);
            for(i = 0; i < len; i++) {
                this[i][methodName].apply(this[i], args);
            }

            return this;
        };
    };

    Konva.Collection.mapMethods = function(constructor) {
        var prot = constructor.prototype;
        for(var methodName in prot) {
            Konva.Collection._mapMethod(methodName);
        }
    };

    /*
    * Last updated November 2011
    * By Simon Sarris
    * www.simonsarris.com
    * sarris@acm.org
    *
    * Free to use and distribute at will
    * So long as you are nice to people, etc
    */

    /*
    * The usage of this class was inspired by some of the work done by a forked
    * project, KineticJS-Ext by Wappworks, which is based on Simon's Transform
    * class.  Modified by Eric Rowell
    */

    /**
     * Transform constructor
     * @constructor
     * @param {Array} [m] Optional six-element matrix
     * @memberof Konva
     */
    Konva.Transform = function(m) {
        this.m = (m && m.slice()) || [1, 0, 0, 1, 0, 0];
    };

    Konva.Transform.prototype = {
        /**
         * Copy Konva.Transform object
         * @method
         * @memberof Konva.Transform.prototype
         * @returns {Konva.Transform}
         */
        copy: function() {
            return new Konva.Transform(this.m);
        },
        /**
         * Transform point
         * @method
         * @memberof Konva.Transform.prototype
         * @param {Object} point 2D point(x, y)
         * @returns {Object} 2D point(x, y)
         */
        point: function(point) {
            var m = this.m;
            return {
                x: m[0] * point.x + m[2] * point.y + m[4],
                y: m[1] * point.x + m[3] * point.y + m[5]
            };
        },
        /**
         * Apply translation
         * @method
         * @memberof Konva.Transform.prototype
         * @param {Number} x
         * @param {Number} y
         * @returns {Konva.Transform}
         */
        translate: function(x, y) {
            this.m[4] += this.m[0] * x + this.m[2] * y;
            this.m[5] += this.m[1] * x + this.m[3] * y;
            return this;
        },
        /**
         * Apply scale
         * @method
         * @memberof Konva.Transform.prototype
         * @param {Number} sx
         * @param {Number} sy
         * @returns {Konva.Transform}
         */
        scale: function(sx, sy) {
            this.m[0] *= sx;
            this.m[1] *= sx;
            this.m[2] *= sy;
            this.m[3] *= sy;
            return this;
        },
        /**
         * Apply rotation
         * @method
         * @memberof Konva.Transform.prototype
         * @param {Number} rad  Angle in radians
         * @returns {Konva.Transform}
         */
        rotate: function(rad) {
            var c = Math.cos(rad);
            var s = Math.sin(rad);
            var m11 = this.m[0] * c + this.m[2] * s;
            var m12 = this.m[1] * c + this.m[3] * s;
            var m21 = this.m[0] * -s + this.m[2] * c;
            var m22 = this.m[1] * -s + this.m[3] * c;
            this.m[0] = m11;
            this.m[1] = m12;
            this.m[2] = m21;
            this.m[3] = m22;
            return this;
        },
        /**
         * Returns the translation
         * @method
         * @memberof Konva.Transform.prototype
         * @returns {Object} 2D point(x, y)
         */
        getTranslation: function() {
            return {
                x: this.m[4],
                y: this.m[5]
            };
        },
        /**
         * Apply skew
         * @method
         * @memberof Konva.Transform.prototype
         * @param {Number} sx
         * @param {Number} sy
         * @returns {Konva.Transform}
         */
        skew: function(sx, sy) {
            var m11 = this.m[0] + this.m[2] * sy;
            var m12 = this.m[1] + this.m[3] * sy;
            var m21 = this.m[2] + this.m[0] * sx;
            var m22 = this.m[3] + this.m[1] * sx;
            this.m[0] = m11;
            this.m[1] = m12;
            this.m[2] = m21;
            this.m[3] = m22;
            return this;
         },
        /**
         * Transform multiplication
         * @method
         * @memberof Konva.Transform.prototype
         * @param {Konva.Transform} matrix
         * @returns {Konva.Transform}
         */
        multiply: function(matrix) {
            var m11 = this.m[0] * matrix.m[0] + this.m[2] * matrix.m[1];
            var m12 = this.m[1] * matrix.m[0] + this.m[3] * matrix.m[1];

            var m21 = this.m[0] * matrix.m[2] + this.m[2] * matrix.m[3];
            var m22 = this.m[1] * matrix.m[2] + this.m[3] * matrix.m[3];

            var dx = this.m[0] * matrix.m[4] + this.m[2] * matrix.m[5] + this.m[4];
            var dy = this.m[1] * matrix.m[4] + this.m[3] * matrix.m[5] + this.m[5];

            this.m[0] = m11;
            this.m[1] = m12;
            this.m[2] = m21;
            this.m[3] = m22;
            this.m[4] = dx;
            this.m[5] = dy;
            return this;
        },
        /**
         * Invert the matrix
         * @method
         * @memberof Konva.Transform.prototype
         * @returns {Konva.Transform}
         */
        invert: function() {
            var d = 1 / (this.m[0] * this.m[3] - this.m[1] * this.m[2]);
            var m0 = this.m[3] * d;
            var m1 = -this.m[1] * d;
            var m2 = -this.m[2] * d;
            var m3 = this.m[0] * d;
            var m4 = d * (this.m[2] * this.m[5] - this.m[3] * this.m[4]);
            var m5 = d * (this.m[1] * this.m[4] - this.m[0] * this.m[5]);
            this.m[0] = m0;
            this.m[1] = m1;
            this.m[2] = m2;
            this.m[3] = m3;
            this.m[4] = m4;
            this.m[5] = m5;
            return this;
        },
        /**
         * return matrix
         * @method
         * @memberof Konva.Transform.prototype
         */
        getMatrix: function() {
            return this.m;
        },
        /**
         * set to absolute position via translation
         * @method
         * @memberof Konva.Transform.prototype
         * @returns {Konva.Transform}
         * @author ericdrowell
         */
        setAbsolutePosition: function(x, y) {
            var m0 = this.m[0],
                m1 = this.m[1],
                m2 = this.m[2],
                m3 = this.m[3],
                m4 = this.m[4],
                m5 = this.m[5],
                yt = ((m0 * (y - m5)) - (m1 * (x - m4))) / ((m0 * m3) - (m1 * m2)),
                xt = (x - m4 - (m2 * yt)) / m0;

            return this.translate(xt, yt);
        }
    };

    // CONSTANTS
    var CONTEXT_2D = '2d',
        OBJECT_ARRAY = '[object Array]',
        OBJECT_NUMBER = '[object Number]',
        OBJECT_STRING = '[object String]',
        PI_OVER_DEG180 = Math.PI / 180,
        DEG180_OVER_PI = 180 / Math.PI,
        HASH = '#',
        EMPTY_STRING = '',
        ZERO = '0',
        KONVA_WARNING = 'Konva warning: ',
        KONVA_ERROR = 'Konva error: ',
        RGB_PAREN = 'rgb(',
        COLORS = {
            aliceblue: [240, 248, 255],
            antiquewhite: [250, 235, 215],
            aqua: [0, 255, 255],
            aquamarine: [127, 255, 212],
            azure: [240, 255, 255],
            beige: [245, 245, 220],
            bisque: [255, 228, 196],
            black: [0, 0, 0],
            blanchedalmond: [255, 235, 205],
            blue: [0, 0, 255],
            blueviolet: [138, 43, 226],
            brown: [165, 42, 42],
            burlywood: [222, 184, 135],
            cadetblue: [95, 158, 160],
            chartreuse: [127, 255, 0],
            chocolate: [210, 105, 30],
            coral: [255, 127, 80],
            cornflowerblue: [100, 149, 237],
            cornsilk: [255, 248, 220],
            crimson: [220, 20, 60],
            cyan: [0, 255, 255],
            darkblue: [0, 0, 139],
            darkcyan: [0, 139, 139],
            darkgoldenrod: [184, 132, 11],
            darkgray: [169, 169, 169],
            darkgreen: [0, 100, 0],
            darkgrey: [169, 169, 169],
            darkkhaki: [189, 183, 107],
            darkmagenta: [139, 0, 139],
            darkolivegreen: [85, 107, 47],
            darkorange: [255, 140, 0],
            darkorchid: [153, 50, 204],
            darkred: [139, 0, 0],
            darksalmon: [233, 150, 122],
            darkseagreen: [143, 188, 143],
            darkslateblue: [72, 61, 139],
            darkslategray: [47, 79, 79],
            darkslategrey: [47, 79, 79],
            darkturquoise: [0, 206, 209],
            darkviolet: [148, 0, 211],
            deeppink: [255, 20, 147],
            deepskyblue: [0, 191, 255],
            dimgray: [105, 105, 105],
            dimgrey: [105, 105, 105],
            dodgerblue: [30, 144, 255],
            firebrick: [178, 34, 34],
            floralwhite: [255, 255, 240],
            forestgreen: [34, 139, 34],
            fuchsia: [255, 0, 255],
            gainsboro: [220, 220, 220],
            ghostwhite: [248, 248, 255],
            gold: [255, 215, 0],
            goldenrod: [218, 165, 32],
            gray: [128, 128, 128],
            green: [0, 128, 0],
            greenyellow: [173, 255, 47],
            grey: [128, 128, 128],
            honeydew: [240, 255, 240],
            hotpink: [255, 105, 180],
            indianred: [205, 92, 92],
            indigo: [75, 0, 130],
            ivory: [255, 255, 240],
            khaki: [240, 230, 140],
            lavender: [230, 230, 250],
            lavenderblush: [255, 240, 245],
            lawngreen: [124, 252, 0],
            lemonchiffon: [255, 250, 205],
            lightblue: [173, 216, 230],
            lightcoral: [240, 128, 128],
            lightcyan: [224, 255, 255],
            lightgoldenrodyellow: [250, 250, 210],
            lightgray: [211, 211, 211],
            lightgreen: [144, 238, 144],
            lightgrey: [211, 211, 211],
            lightpink: [255, 182, 193],
            lightsalmon: [255, 160, 122],
            lightseagreen: [32, 178, 170],
            lightskyblue: [135, 206, 250],
            lightslategray: [119, 136, 153],
            lightslategrey: [119, 136, 153],
            lightsteelblue: [176, 196, 222],
            lightyellow: [255, 255, 224],
            lime: [0, 255, 0],
            limegreen: [50, 205, 50],
            linen: [250, 240, 230],
            magenta: [255, 0, 255],
            maroon: [128, 0, 0],
            mediumaquamarine: [102, 205, 170],
            mediumblue: [0, 0, 205],
            mediumorchid: [186, 85, 211],
            mediumpurple: [147, 112, 219],
            mediumseagreen: [60, 179, 113],
            mediumslateblue: [123, 104, 238],
            mediumspringgreen: [0, 250, 154],
            mediumturquoise: [72, 209, 204],
            mediumvioletred: [199, 21, 133],
            midnightblue: [25, 25, 112],
            mintcream: [245, 255, 250],
            mistyrose: [255, 228, 225],
            moccasin: [255, 228, 181],
            navajowhite: [255, 222, 173],
            navy: [0, 0, 128],
            oldlace: [253, 245, 230],
            olive: [128, 128, 0],
            olivedrab: [107, 142, 35],
            orange: [255, 165, 0],
            orangered: [255, 69, 0],
            orchid: [218, 112, 214],
            palegoldenrod: [238, 232, 170],
            palegreen: [152, 251, 152],
            paleturquoise: [175, 238, 238],
            palevioletred: [219, 112, 147],
            papayawhip: [255, 239, 213],
            peachpuff: [255, 218, 185],
            peru: [205, 133, 63],
            pink: [255, 192, 203],
            plum: [221, 160, 203],
            powderblue: [176, 224, 230],
            purple: [128, 0, 128],
            rebeccapurple: [102, 51, 153],
            red: [255, 0, 0],
            rosybrown: [188, 143, 143],
            royalblue: [65, 105, 225],
            saddlebrown: [139, 69, 19],
            salmon: [250, 128, 114],
            sandybrown: [244, 164, 96],
            seagreen: [46, 139, 87],
            seashell: [255, 245, 238],
            sienna: [160, 82, 45],
            silver: [192, 192, 192],
            skyblue: [135, 206, 235],
            slateblue: [106, 90, 205],
            slategray: [119, 128, 144],
            slategrey: [119, 128, 144],
            snow: [255, 255, 250],
            springgreen: [0, 255, 127],
            steelblue: [70, 130, 180],
            tan: [210, 180, 140],
            teal: [0, 128, 128],
            thistle: [216, 191, 216],
            transparent: [255, 255, 255, 0],
            tomato: [255, 99, 71],
            turquoise: [64, 224, 208],
            violet: [238, 130, 238],
            wheat: [245, 222, 179],
            white: [255, 255, 255],
            whitesmoke: [245, 245, 245],
            yellow: [255, 255, 0],
            yellowgreen: [154, 205, 5]
        },

        RGB_REGEX = /rgb\((\d{1,3}),(\d{1,3}),(\d{1,3})\)/;

    /**
     * @namespace Util
     * @memberof Konva
     */
    Konva.Util = {
        /*
         * cherry-picked utilities from underscore.js
         */
        _isElement: function(obj) {
            return !!(obj && obj.nodeType == 1);
        },
        _isFunction: function(obj) {
            return !!(obj && obj.constructor && obj.call && obj.apply);
        },
        _isObject: function(obj) {
            return (!!obj && obj.constructor === Object);
        },
        _isArray: function(obj) {
            return Object.prototype.toString.call(obj) === OBJECT_ARRAY;
        },
        _isNumber: function(obj) {
            return Object.prototype.toString.call(obj) === OBJECT_NUMBER;
        },
        _isString: function(obj) {
            return Object.prototype.toString.call(obj) === OBJECT_STRING;
        },
        // Returns a function, that, when invoked, will only be triggered at most once
        // during a given window of time. Normally, the throttled function will run
        // as much as it can, without ever going more than once per `wait` duration;
        // but if you'd like to disable the execution on the leading edge, pass
        // `{leading: false}`. To disable execution on the trailing edge, ditto.
        _throttle: function(func, wait, opts) {
            var context, args, result;
            var timeout = null;
            var previous = 0;
            var options = opts || {};
            var later = function() {
                previous = options.leading === false ? 0 : new Date().getTime();
                timeout = null;
                result = func.apply(context, args);
                context = args = null;
            };
            return function() {
                var now = new Date().getTime();
                if (!previous && options.leading === false) {
                    previous = now;
                }
                var remaining = wait - (now - previous);
                context = this;
                args = arguments;
                if (remaining <= 0) {
                  clearTimeout(timeout);
                  timeout = null;
                  previous = now;
                  result = func.apply(context, args);
                  context = args = null;
                } else if (!timeout && options.trailing !== false) {
                  timeout = setTimeout(later, remaining);
                }
                return result;
            };
        },
        /*
         * other utils
         */
        _hasMethods: function(obj) {
            var names = [],
                key;

            for(key in obj) {
                if (!obj.hasOwnProperty(key)) {
                    continue;
                }
                if(this._isFunction(obj[key])) {
                    names.push(key);
                }
            }
            return names.length > 0;
        },
        isValidSelector: function(selector) {
            if (typeof selector !== 'string') {
                return false;
            }
            var firstChar = selector[0];
            return firstChar === '#' || firstChar === '.' || firstChar === firstChar.toUpperCase();
        },
        createCanvasElement: function() {
            var canvas = Konva.document.createElement('canvas');
            // on some environments canvas.style is readonly
            try {
                canvas.style = canvas.style || {};
            } catch (e) {
            }
            return canvas;
        },
        isBrowser: function() {
            return (typeof exports !== 'object');
        },
        _isInDocument: function(el) {
            while(el = el.parentNode) {
                if(el == Konva.document) {
                    return true;
                }
            }
            return false;
        },
        _simplifyArray: function(arr) {
            var retArr = [],
                len = arr.length,
                util = Konva.Util,
                n, val;

            for (n = 0; n < len; n++) {
                val = arr[n];
                if (util._isNumber(val)) {
                    val = Math.round(val * 1000) / 1000;
                }
                else if (!util._isString(val)) {
                    val = val.toString();
                }

                retArr.push(val);
            }

            return retArr;
        },
        /*
         * arg can be an image object or image data
         */
        _getImage: function(arg, callback) {
            var imageObj, canvas;

            // if arg is null or undefined
            if(!arg) {
                callback(null);
            }

            // if arg is already an image object
            else if(this._isElement(arg)) {
                callback(arg);
            }

            // if arg is a string, then it's a data url
            else if(this._isString(arg)) {
                imageObj = new Konva.window.Image();
                imageObj.onload = function() {
                    callback(imageObj);
                };
                imageObj.src = arg;
            }

            //if arg is an object that contains the data property, it's an image object
            else if(arg.data) {
                canvas = Konva.Util.createCanvasElement();
                canvas.width = arg.width;
                canvas.height = arg.height;
                var _context = canvas.getContext(CONTEXT_2D);
                _context.putImageData(arg, 0, 0);
                this._getImage(canvas.toDataURL(), callback);
            }
            else {
                callback(null);
            }
        },
        _getRGBAString: function(obj) {
            var red = obj.red || 0,
                green = obj.green || 0,
                blue = obj.blue || 0,
                alpha = obj.alpha || 1;

            return [
                'rgba(',
                red,
                ',',
                green,
                ',',
                blue,
                ',',
                alpha,
                ')'
            ].join(EMPTY_STRING);
        },
        _rgbToHex: function(r, g, b) {
            return ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
        },
        _hexToRgb: function(hex) {
            hex = hex.replace(HASH, EMPTY_STRING);
            var bigint = parseInt(hex, 16);
            return {
                r: (bigint >> 16) & 255,
                g: (bigint >> 8) & 255,
                b: bigint & 255
            };
        },
        /**
         * return random hex color
         * @method
         * @memberof Konva.Util.prototype
         */
        getRandomColor: function() {
            var randColor = (Math.random() * 0xFFFFFF << 0).toString(16);
            while (randColor.length < 6) {
                randColor = ZERO + randColor;
            }
            return HASH + randColor;
        },
        /**
         * return value with default fallback
         * @method
         * @memberof Konva.Util.prototype
         */
        get: function(val, def) {
            if (val === undefined) {
                return def;
            }
            else {
                return val;
            }
        },
        /**
         * get RGB components of a color
         * @method
         * @memberof Konva.Util.prototype
         * @param {String} color
         * @example
         * // each of the following examples return {r:0, g:0, b:255}
         * var rgb = Konva.Util.getRGB('blue');
         * var rgb = Konva.Util.getRGB('#0000ff');
         * var rgb = Konva.Util.getRGB('rgb(0,0,255)');
         */
        getRGB: function(color) {
            var rgb;
            // color string
            if (color in COLORS) {
                rgb = COLORS[color];
                return {
                    r: rgb[0],
                    g: rgb[1],
                    b: rgb[2]
                };
            }
            // hex
            else if (color[0] === HASH) {
                return this._hexToRgb(color.substring(1));
            }
            // rgb string
            else if (color.substr(0, 4) === RGB_PAREN) {
                rgb = RGB_REGEX.exec(color.replace(/ /g, ''));
                return {
                    r: parseInt(rgb[1], 10),
                    g: parseInt(rgb[2], 10),
                    b: parseInt(rgb[3], 10)
                };
            }
            // default
            else {
                return {
                    r: 0,
                    g: 0,
                    b: 0
                };
            }
        },
        // convert any color string to RGBA object
        // from https://github.com/component/color-parser
        colorToRGBA: function(str) {
            str = str || 'black';
            return Konva.Util._namedColorToRBA(str)
                || Konva.Util._hex3ColorToRGBA(str)
                || Konva.Util._hex6ColorToRGBA(str)
                || Konva.Util._rgbColorToRGBA(str)
                || Konva.Util._rgbaColorToRGBA(str);
        },
        // Parse named css color. Like "green"
        _namedColorToRBA: function(str) {
            var c = COLORS[str.toLowerCase()];
            if (!c) {
                return null;
            }
            return {
                r: c[0],
                g: c[1],
                b: c[2],
                a: 1
            };
        },
        // Parse rgb(n, n, n)
        _rgbColorToRGBA: function(str) {
            if (str.indexOf('rgb(') === 0) {
                str = str.match(/rgb\(([^)]+)\)/)[1];
                var parts = str.split(/ *, */).map(Number);
                return {
                    r: parts[0],
                    g: parts[1],
                    b: parts[2],
                    a: 1
                };
            }
        },
        // Parse rgba(n, n, n, n)
        _rgbaColorToRGBA: function(str) {
            if (str.indexOf('rgba(') === 0) {
                str = str.match(/rgba\(([^)]+)\)/)[1];
                var parts = str.split(/ *, */).map(Number);
                return {
                    r: parts[0],
                    g: parts[1],
                    b: parts[2],
                    a: parts[3]
                };
            }

        },
        // Parse #nnnnnn
        _hex6ColorToRGBA: function(str) {
            if ((str[0] === '#') && (str.length === 7)) {
                return {
                    r: parseInt(str.slice(1, 3), 16),
                    g: parseInt(str.slice(3, 5), 16),
                    b: parseInt(str.slice(5, 7), 16),
                    a: 1
                };
            }
        },
        // Parse #nnn
        _hex3ColorToRGBA: function(str) {
            if ((str[0] === '#') && (str.length === 4)) {
                return {
                    r: parseInt(str[1] + str[1], 16),
                    g: parseInt(str[2] + str[2], 16),
                    b: parseInt(str[3] + str[3], 16),
                    a: 1
                };
            }
        },
        // o1 takes precedence over o2
        _merge: function(o1, o2) {
            var retObj = this._clone(o2);
            for(var key in o1) {
                if(this._isObject(o1[key])) {
                    retObj[key] = this._merge(o1[key], retObj[key]);
                }
                else {
                    retObj[key] = o1[key];
                }
            }
            return retObj;
        },
        cloneObject: function(obj) {
            var retObj = {};
            for(var key in obj) {
                if(this._isObject(obj[key])) {
                    retObj[key] = this.cloneObject(obj[key]);
                }
                else if (this._isArray(obj[key])) {
                    retObj[key] = this.cloneArray(obj[key]);
                } else {
                    retObj[key] = obj[key];
                }
            }
            return retObj;
        },
        cloneArray: function(arr) {
            return arr.slice(0);
        },
        _degToRad: function(deg) {
            return deg * PI_OVER_DEG180;
        },
        _radToDeg: function(rad) {
            return rad * DEG180_OVER_PI;
        },
        _capitalize: function(str) {
            return str.charAt(0).toUpperCase() + str.slice(1);
        },
        throw: function(str) {
            throw new Error(KONVA_ERROR + str);
        },
        error: function(str) {
          console.error(KONVA_ERROR + str);
        },
        warn: function(str) {
            /*
             * IE9 on Windows7 64bit will throw a JS error
             * if we don't use window.console in the conditional
             */
            if(Konva.global.console && console.warn && Konva.showWarnings) {
                console.warn(KONVA_WARNING + str);
            }
        },
        extend: function(child, parent) {
            function Ctor() {
                this.constructor = child;
            }
            Ctor.prototype = parent.prototype;
            var oldProto = child.prototype;
            child.prototype = new Ctor();
            for (var key in oldProto) {
                if (oldProto.hasOwnProperty(key)) {
                    child.prototype[key] = oldProto[key];
                }
            }
            child.__super__ = parent.prototype;
            // create reference to parent
            child.super = parent;
        },
        /**
         * adds methods to a constructor prototype
         * @method
         * @memberof Konva.Util.prototype
         * @param {Function} constructor
         * @param {Object} methods
         */
        addMethods: function(constructor, methods) {
            var key;

            for (key in methods) {
                constructor.prototype[key] = methods[key];
            }
        },
        _getControlPoints: function(x0, y0, x1, y1, x2, y2, t) {
            var d01 = Math.sqrt(Math.pow(x1 - x0, 2) + Math.pow(y1 - y0, 2)),
                d12 = Math.sqrt(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2)),
                fa = t * d01 / (d01 + d12),
                fb = t * d12 / (d01 + d12),
                p1x = x1 - fa * (x2 - x0),
                p1y = y1 - fa * (y2 - y0),
                p2x = x1 + fb * (x2 - x0),
                p2y = y1 + fb * (y2 - y0);

            return [p1x, p1y, p2x, p2y];
        },
        _expandPoints: function(p, tension) {
            var len = p.length,
                allPoints = [],
                n, cp;

            for (n = 2; n < len - 2; n += 2) {
                cp = Konva.Util._getControlPoints(p[n - 2], p[n - 1], p[n], p[n + 1], p[n + 2], p[n + 3], tension);
                allPoints.push(cp[0]);
                allPoints.push(cp[1]);
                allPoints.push(p[n]);
                allPoints.push(p[n + 1]);
                allPoints.push(cp[2]);
                allPoints.push(cp[3]);
            }

            return allPoints;
        },
        _removeLastLetter: function(str) {
            return str.substring(0, str.length - 1);
        },
        each: function(obj, func) {
            for (var key in obj) {
                func(key, obj[key]);
            }
        },
        _getProjectionToSegment: function(x1, y1, x2, y2, x3, y3) {
            var x, y, dist;

            var pd2 = (x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2);
            if(pd2 == 0) {
                x = x1;
                y = y1;
                dist = (x3 - x2) * (x3 - x2) + (y3 - y2) * (y3 - y2);
            } else {
                var u = ((x3 - x1) * (x2 - x1) + (y3 - y1) * (y2 - y1)) / pd2;
                if(u < 0) {
                    x = x1;
                    y = y1;
                    dist = (x1 - x3) * (x1 - x3) + (y1 - y3) * (y1 - y3);
                } else if (u > 1.0) {
                    x = x2;
                    y = y2;
                    dist = (x2 - x3) * (x2 - x3) + (y2 - y3) * (y2 - y3);
                } else {
                    x = x1 + u * (x2 - x1);
                    y = y1 + u * (y2 - y1);
                    dist = (x - x3) * (x - x3) + (y - y3) * (y - y3);
                }
            }
            return [x, y, dist];
        },
        // line as array of points.
        // line might be closed
        _getProjectionToLine: function(pt, line, isClosed) {
            var pc = Konva.Util.cloneObject(pt);
            var dist = Number.MAX_VALUE;
            line.forEach(function(p1, i) {
                if (!isClosed && i === line.length - 1) {
                    return;
                }
                var p2 = line[(i + 1) % line.length];
                var proj = Konva.Util._getProjectionToSegment(p1.x, p1.y, p2.x, p2.y, pt.x, pt.y);
                var px = proj[0], py = proj[1], pdist = proj[2];
                if (pdist < dist) {
                    pc.x = px;
                    pc.y = py;
                    dist = pdist;
                }
            });
            return pc;
        },
        _prepareArrayForTween: function(startArray, endArray, isClosed) {
            var n, start = [], end = [];
            if (startArray.length > endArray.length) {
                var temp = endArray;
                endArray = startArray;
                startArray = temp;
            }
            for (n = 0; n < startArray.length; n += 2) {
                start.push({
                    x: startArray[n],
                    y: startArray[n + 1]
                });
            }
            for (n = 0; n < endArray.length; n += 2) {
                end.push({
                    x: endArray[n],
                    y: endArray[n + 1]
                });
            }


            var newStart = [];
            end.forEach(function(point) {
                var pr = Konva.Util._getProjectionToLine(point, start, isClosed);
                newStart.push(pr.x);
                newStart.push(pr.y);
            });
            return newStart;
        }
    };
})();