import numpy as np
from mayavi import mlab
from matplotlib.scale import scale_factory
from traits.api import HasTraits, Range, Instance, Array,
    on_trait_change
from traitsui.api import View, Item, Group
from mayavi.core.pipeline_base import PipelineBase
from mayavi.core.ui.api import MayaviScene, SceneEditor,
            MlabSceneModel

class Modell(HasTraits):
  p = Array
  n = Range(0, 9, 5)
  #p is a 4 dimensional Array p[10][20][20][20]
  scene = Instance(MlabSceneModel, ())
  plot = Instance(PipelineBase)

  @on_trait_change('n,scene.activated')
  def update_plot(self):
     self.src = mlab.pipeline.scalar_field(self.p[self.n])
     if self.plot is None:
        self.plot = self.scene.mlab.pipeline.image_plane_widget(self.src,
                        plane_orientation='z_axes',
                        slice_index=10,
                        vmin=0, vmax=120)
  else:
     '''here should be the update function, i tried using mlab_source.set(self.src=self.src)
     and all variations of expressions in the brackets but nothing worked.
     I also searched for functions in IPW itself but didn't find something that could help me.'''

  #The layout of the dialog created
  view = View(Item('scene', editor=SceneEditor(scene_class=MayaviScene),
                 height=400, width=400, show_label=False),
            Group('_', 'n'),
            resizable=True,
            )

my_model = Modell(p=p)
my_model.configure_traits()