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@charlesjolley
Created August 21, 2012 03:57
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Adding event locks to Ember
# example view implements a simple dragging for mouse events.
Wall.DevView = Ember.View.extend
mouseDown: (ev) ->
ev.dispatcher.lock @, 'mouseMove', 'mouseUp'
@_mouseDown = @$().offset()
@_mouseDown.pageX = ev.pageX
@_mouseDown.pageY = ev.pageY
@_mouseDown.dispatcher = ev.dispatcher
console.log 'mouseDown'
mouseMove: (ev) ->
return unless @_mouseDown
left = @_mouseDown.left + ev.pageX - @_mouseDown.pageX
top = @_mouseDown.top + ev.pageY - @_mouseDown.pageY
@$().offset { left: left, top: top }
console.log 'mouseMove'
mouseUp: (ev) ->
return unless @_mouseDown
@_mouseDown.dispatcher.unlock 'mouseMove', 'mouseUp'
left = @_mouseDown.left + ev.pageX - @_mouseDown.pageX
top = @_mouseDown.top + ev.pageY - @_mouseDown.pageY
@$().offset { left: left, top: top }
@_mouseDown = null
console.log 'mouseUp'
# add ability to lock focus on a view for specific events.
# Call before you create your application instance.
Ember.EventDispatcher.reopen
_bubbleEvent: (view, evt, eventName) ->
view = @_locks[eventName] if @_locks?[eventName]
evt.dispatcher = @
@_super view, evt, eventName
lock: (view, eventNames...) ->
@_locks = {} if not @_locks
eventNames.forEach (eventName) => @_locks[eventName] = view
unlock: (eventNames...) ->
return if not @_locks
eventNames.forEach (eventName) => delete @_locks[eventName]
Ember just sends events to whatever view your mouse or finger happens to be under. This causes really annoying breakage when trying to drag views around on the screen. This monkey patch adds the ability for an EventDispatcher to 'lock' delivery of some events to a particular view, so you can solve this.
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