Stolen from https://github.com/dbottillo/SlideOutNavigationRubyMotion/blob/master/app/controllers/menu_view_controller.rb Pan Gesture recognizer. (slide view up and down)

gistfile1.rb

def viewDidLoad 
    panGesture = UIPanGestureRecognizer.alloc.initWithTarget(self, action: "pan:")
    panGesture.delegate = self
    modal_view.addGestureRecognizer(panGesture)
  end

  def pan(gesture)
    piece = gesture.view
    adjustAnchorPointForGestureRecognizer(gesture)

    if (gesture.state == UIGestureRecognizerStateBegan || gesture.state == UIGestureRecognizerStateChanged) then
      translation = gesture.translationInView(piece.superview)

      x = piece.center.x + translation.x
      y = piece.center.y + translation.y


      # Some dimension to play with bounds.. This could be something like App.bounds.size.width (or height)
      #if x > -217.0
      #  x = -217.0
      #end

      #if x < 290.0
      #  x = 290.0
      #end

      #if y < 53.0
      #  puts 'y == ' + y.to_s
      #  y = 53.0
      #end

      #if y > 468.0
      #  puts 'y > 468 == ' + y.to_s
      #  y = 468.00
      #end

      piece.setCenter(CGPointMake(x,y))
      gesture.setTranslation(CGPointZero, inView:piece.superview)
    else
      slideThenHide if gesture.state == UIGestureRecognizerStateEnded
    end
  end

  def slideThenHide
    #Add some code to slide th view down and make it transparent.
  end

  def adjustAnchorPointForGestureRecognizer(gestureRecognizer)
    if (gestureRecognizer.state == UIGestureRecognizerStateBegan) then
      piece = gestureRecognizer.view
      locationInView = gestureRecognizer.locationInView(piece)
      locationInSuperView = gestureRecognizer.locationInView(piece.superview)

      x = locationInView.x / piece.bounds.size.width
      y = locationInView.y / piece.bounds.size.height
      piece.layer.anchorPoint = CGPointMake(x,y)
      piece.center = locationInSuperView
    end
  end