Change draggable interface

src/ui/draggable.coffee

@@ -1,17 +1,23 @@
 _ = require "underscore"
 
+{EventEmitter} = require "../eventemitter"
 {Events} = require "../primitives/events"
 
-class exports.Draggable
+# Add specific events for draggable
+Events.DragStart = "dragstart"
+Events.DragMove = "dragmove"
+Events.DragEnd = "dragend"
+
+# Make any view draggable
+
+class exports.Draggable extends EventEmitter
+
+	@VelocityTimeOut = 100
 
 	constructor: (@view) ->
 
 		@speed = {x:1.0, y:1.0}
 
-		if @view.__draggable
-			console.error "Draggable: already registered draggable for #{@view.name}"
-
-		@view.__draggable = @
 		@_deltas = []
 		@_isDragging = false
 
@@ -20,14 +26,39 @@ class exports.Draggable
 	attach: -> @view.on  Events.TouchStart, @_touchStart
 	remove: -> @view.off Events.TouchStart, @_touchStart
 
+	calculateVelocity: ->
+
+		if @_deltas.length < 2
+			return {x:0, y:0}
+
+		curr = @_deltas[-1..-1][0]
+		prev = @_deltas[-2..-2][0]
+		time = curr.t - prev.t
+
+		# Bail out if the last move updates where a while ago
+		timeSinceLastMove = (new Date().getTime() - prev.t)
+
+		if timeSinceLastMove > @VelocityTimeOut
+			return {x:0, y:0}
+
+		velocity =
+			x: (curr.x - prev.x) / time
+			y: (curr.y - prev.y) / time
+
+		velocity.x = 0 if velocity.x is Infinity
+		velocity.y = 0 if velocity.y is Infinity
+
+		velocity
+
 	_updatePosition: (event) =>
 
-		touchEvent = Events.sanitize event
+		touchEvent = Events.touchEvent event
 
 		delta = 
 			x: touchEvent.clientX - @_start.x
 			y: touchEvent.clientY - @_start.y
-
+
+		# Correct for current drag speed
 		correctedDelta = 
 			x: delta.x * @speed.x
 			y: delta.y * @speed.y
@@ -46,7 +77,7 @@ class exports.Draggable
 
 		@_isDragging = true
 
-		touchEvent = Events.sanitize event
+		touchEvent = Events.touchEvent event
 
 		@_start =
 			x: touchEvent.clientX
@@ -59,7 +90,7 @@ class exports.Draggable
 		document.addEventListener Events.TouchMove, @_updatePosition
 		document.addEventListener Events.TouchEnd, @_touchEnd
 
-		@view.emit Events.DragStart, event
+		@emit Events.DragStart, event
 
 	_touchEnd: (event) => 
 
@@ -68,58 +99,6 @@ class exports.Draggable
 		document.removeEventListener Events.TouchMove, @_updatePosition
 		document.removeEventListener Events.TouchEnd, @_touchEnd
 
-		@view.emit Events.DragEnd, event
-		@_deltas = []
-
-	_calculateVelocity: (time=20) =>
+		@emit Events.DragEnd, event
 
-		if @_deltas.length < 2
-			return {x:0, y:0}
-
-		curr = @_deltas[-1..-1][0]
-		prev = @_deltas[-2..-2][0]
-		time = curr.t - prev.t
-
-		# Bail out if the last move updates where a while ago
-		timeSinceLastMove = (new Date().getTime() - prev.t)
-
-		if timeSinceLastMove > 100
-			return {x:0, y:0}
-
-		velocity =
-			x: (curr.x - prev.x) / time
-			y: (curr.y - prev.y) / time
-
-		velocity.x = 0 if velocity.x is Infinity
-		velocity.y = 0 if velocity.y is Infinity
-
-		velocity
-
-	_calculateAverageVelocity: (time=100) =>
-
-		if @_deltas.length < 2
-			return {x:0, y:0} 
-
-		currTime = lastTime = _.last(@_deltas).t
-
-		deltas = for i in [@_deltas.length - 1..0] by -1
-
-			currDelta = @_deltas[i]
-			currTime = currDelta.t
-
-			if currTime < (lastTime - time)
-				break
-
-			currDelta
-
-		totalDelta = 
-			x: utils.sum(_.pluck deltas, "x")
-			y: utils.sum(_.pluck deltas, "y")
-
-		totalTime = _.first(deltas).t - _.last(deltas).t
-
-		return {x:0, y:0} if totalTime is 0
-
-		velocity =
-			x: (totalDelta.x / totalTime)
-			y: (totalDelta.y / totalTime)
+		@_deltas = []