layer.draggable.velocity < object>

Current velocity for the draggable layer. The velocity is read-only.
译：拖动图层的当前速度。 速度是只读的。

layerA = new Layer
layerA.draggable.enabled = true

# On DragMove, print the x and y velocity 
layerA.draggable.on Events.DragMove, ->
    print layerA.draggable.velocity