1+ ( function ( global ) {
2+
3+ function extend ( obj ) {
4+ for ( var i = 1 ; i < arguments . length ; i ++ ) {
5+ var source = arguments [ i ] ;
6+ for ( var name in source ) if ( source . hasOwnProperty ( name ) )
7+ obj [ name ] = source [ name ] ;
8+ }
9+ return obj ;
10+ }
11+
12+ var EventEmitter = {
13+ on : function ( type , handler ) {
14+ this . _ensureEvent ( type ) ;
15+ this . _events [ type ] . push ( handler ) ;
16+ } ,
17+ off : function ( type , handler ) {
18+ if ( this . _events && this . _events [ type ] ) {
19+ this . _events [ type ] = this . _events [ type ] . filter ( function ( h ) {
20+ return h !== handler ;
21+ } ) ;
22+ }
23+ } ,
24+ emit : function ( type ) {
25+ var args = Array . prototype . slice . call ( arguments , 1 ) ;
26+ this . _ensureEvent ( type ) ;
27+ this . _events [ type ] . forEach ( function ( handler ) {
28+ handler . apply ( this , args ) ;
29+ } ) ;
30+ } ,
31+ _ensureEvent : function ( type ) {
32+ if ( ! this . _events ) this . _events = { } ;
33+ if ( ! this . _events [ type ] ) this . _events [ type ] = [ ] ;
34+ }
35+ } ;
36+
37+ function Vector2d ( x , y ) {
38+ this . x = x ;
39+ this . y = y ;
40+ }
41+
42+ Object . defineProperty ( Vector2d . prototype , 'length' , {
43+ get : function ( ) { return Math . sqrt ( this . x * this . x + this . y * this . y ) ; } ,
44+ enumerable : true
45+ } ) ;
46+
47+ Vector2d . prototype . add = function ( v ) {
48+ if ( v instanceof this . constructor )
49+ return new this . constructor ( this . x + v . x , this . y + v . y ) ;
50+ else
51+ return new this . constructor ( this . x + v , this . y + v ) ;
52+ } ;
53+
54+ Vector2d . prototype . sub = function ( v ) {
55+ if ( v instanceof this . constructor )
56+ return this . add ( v . neg ( ) ) ;
57+ else
58+ return this . add ( - v ) ;
59+ } ;
60+
61+ Vector2d . prototype . neg = function ( ) {
62+ return new this . constructor ( - this . x , - this . y ) ;
63+ } ;
64+
65+ Vector2d . prototype . scale = function ( s ) {
66+ return new this . constructor ( this . x * s , this . y * s ) ;
67+ } ;
68+
69+ Vector2d . prototype . dot = function ( v ) {
70+ return this . x * v . x + this . y * v . y ;
71+ } ;
72+
73+ Vector2d . prototype . cross = function ( v ) {
74+ return this . x * v . y - this . y * v . x ;
75+ } ;
76+
77+ Vector2d . prototype . towards = function ( other ) {
78+ return other . sub ( this ) . normalize ( ) ;
79+ } ;
80+
81+ Vector2d . prototype . normalize = function ( ) {
82+ return this . scale ( 1 / this . length ) ;
83+ } ;
84+
85+ Vector2d . random = function ( unit ) {
86+ var r = Math . random ( ) * Math . PI * 2 ,
87+ d = unit ? 1 : Math . random ( ) ;
88+ return new this (
89+ d * Math . cos ( r ) ,
90+ d * Math . sin ( r )
91+ ) ;
92+ } ;
93+
94+ Vector2d . randomWithin = function ( rectangle ) {
95+ return new this (
96+ rectangle . corner . x + Math . random ( ) * rectangle . width ,
97+ rectangle . corner . y + Math . random ( ) * rectangle . height
98+ ) ;
99+ } ;
100+
101+ Vector2d . prototype . rotate = function ( r ) {
102+ return new this . constructor (
103+ this . x * Math . cos ( r ) - this . y * Math . sin ( r ) ,
104+ this . x * Math . sin ( r ) + this . y * Math . cos ( r )
105+ ) ;
106+ } ;
107+
108+ Vector2d . prototype . clone = function ( ) {
109+ return new this . constructor ( this . x , this . y ) ;
110+ } ;
111+
112+ function BezierCurve ( A , B , C , D ) {
113+ this . _A = A ;
114+ this . _B = B ;
115+ this . _C = C ;
116+ this . _D = D ;
117+ } ;
118+
119+ extend ( BezierCurve . prototype , EventEmitter ) ;
120+
121+ [ 'A' , 'B' , 'C' , 'D' ] . forEach ( function ( pt ) {
122+ Object . defineProperty ( BezierCurve . prototype , pt , {
123+ get : function ( ) { return this [ '_' + pt ] ; } ,
124+ set : function ( v ) {
125+ this [ '_' + pt ] = v ;
126+ this . emit ( 'change' , pt ) ;
127+ }
128+ } ) ;
129+ } ) ;
130+
131+ BezierCurve . prototype . interpolate = function ( t ) {
132+ var tt = t * t ,
133+ ttt = tt * t ,
134+ u = 1 - t ,
135+ uu = u * u ,
136+ uuu = uu * u ;
137+
138+ return this . A . scale ( uuu ) .
139+ add ( this . B . scale ( 3 * uu * t ) ) .
140+ add ( this . C . scale ( 3 * u * tt ) ) .
141+ add ( this . D . scale ( ttt ) ) ;
142+ } ;
143+
144+ // Derivative to determine the curve's slope.
145+ BezierCurve . prototype . direction = function ( t ) {
146+ var tt = t * t ,
147+ g = ( t - 1 ) * ( t - 1 ) ,
148+ h = - 3 * tt + 4 * t - 1 ,
149+ i = 3 * tt - 2 * t ,
150+ j = - tt ;
151+
152+ return this . A . scale ( g ) .
153+ add ( this . B . scale ( h ) ) .
154+ add ( this . C . scale ( i ) ) .
155+ add ( this . D . scale ( j ) ) .
156+ scale ( - 3 ) ;
157+ } ;
158+
159+ function AnimationGenerator ( options ) {
160+ this . options = extend ( { } , this . constructor . defaults , options || { } ) ;
161+ }
162+
163+ AnimationGenerator . defaults = {
164+ segments : 128 ,
165+ orientAlongPath : false ,
166+ maxError : 1 ,
167+ name : 'CUSTOM_ANIMATION'
168+ } ;
169+
170+ AnimationGenerator . prototype . generate = function ( bezier ) {
171+ return this . generateAnimation ( this . generatePointList ( bezier ) ) ;
172+ } ;
173+
174+ AnimationGenerator . prototype . generatePointList = function ( bezier ) {
175+ var increment = 1 / this . options . segments ,
176+ points = [ ] ,
177+ i , p , t , d , pa , n , minD , minError = 0 , idx ;
178+
179+ for ( var i = 0 ; i <= this . options . segments ; i ++ ) {
180+ var t = i * increment ,
181+ p = bezier . interpolate ( t ) ;
182+ p . t = t ;
183+ p . dir = bezier . direction ( t ) ;
184+ p . angle = - Math . atan2 ( p . dir . x , p . dir . y ) / Math . PI * 180 ;
185+ points . push ( p ) ;
186+ }
187+
188+ // Cull as many points as possible from the generated segments
189+ // while the error is less than the maximum allowed.
190+ do {
191+ if ( points . length == 2 ) break ;
192+
193+ idx = null ;
194+ minError = Infinity ;
195+
196+ for ( i = 1 ; i < points . length - 1 ; i ++ ) {
197+ n = points [ i - 1 ] . towards ( points [ i + 1 ] ) ;
198+ pa = points [ i - 1 ] . sub ( points [ i ] ) ;
199+ d = pa . sub ( n . scale ( pa . dot ( n ) ) ) . length ;
200+ if ( d < minError && d < this . options . maxError ) {
201+ minError = d ;
202+ idx = i ;
203+ }
204+ }
205+
206+ if ( idx != null ) points . splice ( idx , 1 ) ;
207+
208+ } while ( minError <= this . options . maxError )
209+
210+ return points ;
211+ }
212+
213+ AnimationGenerator . prototype . generateAnimation = function ( pointList ) {
214+ var i , rollingSum = 0 , total = 0 ,
215+ animation = [ '@-webkit-keyframes ' + this . options . name + ' {' ] ;
216+
217+ pointList [ 0 ] . l = 0 ;
218+ for ( i = 1 ; i < pointList . length ; i ++ ) {
219+ total += pointList [ i ] . l = pointList [ i ] . sub ( pointList [ i - 1 ] ) . length ;
220+ }
221+
222+ for ( i = 0 ; i < pointList . length ; i ++ ) {
223+ rollingSum += pointList [ i ] . l ;
224+ animation . push ( this . _generateKeyframe ( rollingSum / total , pointList [ i ] ) ) ;
225+ }
226+
227+ animation . push ( '}' ) ;
228+ return animation . join ( '\n' ) ;
229+ } ;
230+
231+ AnimationGenerator . prototype . _generateKeyframe = function ( position , point ) {
232+ var extras = '' ;
233+ if ( this . options . orientAlongPath ) {
234+ extras = 'rotate(' + point . angle . toFixed ( 1 ) + 'deg)' ;
235+ }
236+ return ' ' + ( position * 100 ) . toFixed ( 4 ) + '% { -webkit-transform: translate(' + ( point . x . toFixed ( 1 ) ) + 'px, ' + ( point . y . toFixed ( 1 ) ) + 'px) ' + extras + '; }' ;
237+ } ;
238+
239+ // exports
240+ global . Vector2d = Vector2d ;
241+ global . BezierCurve = BezierCurve ;
242+ global . AnimationGenerator = AnimationGenerator ;
243+
244+ } ) ( ( typeof module != 'undefined' && module . exports ) ? module . exports : window ) ;
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