ボリュームスライサの高度な例¶
体積データ上に3つの切断面を表示する3平面ビューと，各切断面を表示する側面ビューを，他の切断面を移動するカーソルで効率的に実装します．
これは，複雑なコールバック対話の例です．それは ボリュームスライサの例 の上に構築されますが，より複雑な論理を持っています．まずは ボリュームスライサの例 を理解するようにしてください．
この例では，VolumeSlicerオブジェクトは，切断位置を示す位置アトリビュートをデータ座標で表示します．この位置アトリビュートが修正されると，Traitsコールバックを使用して切断面を移動します．
3次元ウィンドウでは，ImagePlaneWidgetsを使用して3次元カットが3次元ボリュームデータをカットして表示されます．ImagePlaneWidgetによってプロット用に抽出されたデータは，TVTKのImagePlaneWidgetの _get_reslice_output メソッドを使用してキャプチャされます．作成されたデータセットは，別のImagePlaneWidgetを使用して各側面ビューにプロットされます．その結果，データはコピーされず(VTKレベルでは，パイプラインは1つしかありません)，(たとえば，これらの平面を移動すると)3次元ビュー内の平面にプロットされたデータの変更内容は，VTKパイプラインによって2次元側面ビューに伝達されます．
各側面図には，記号を使用してカーソルが表示されます．カーソルは切断位置を示します．
側面ビューでは，マウスボタンを平面上で押すと，VTKの InteractionEvent が作成されます．この場合，VTKはカットの位置を移動するためのコールバック(observer，VTKの項目)を呼び出します．残りの処理はTraitsコールバックが行います．
Pythonソースコード: volume_slicer_advanced.py
import numpy as np
from traits.api import HasTraits, Instance, Array, \
Bool, Dict, on_trait_change
from traitsui.api import View, Item, HGroup, Group
from tvtk.api import tvtk
from tvtk.pyface.scene import Scene
from mayavi import mlab
from mayavi.core.api import PipelineBase, Source
from mayavi.core.ui.api import SceneEditor, MlabSceneModel
################################################################################
# The object implementing the dialog
class VolumeSlicer(HasTraits):
# The data to plot
data = Array
# The position of the view
position = Array(shape=(3,))
# The 4 views displayed
scene3d = Instance(MlabSceneModel, ())
scene_x = Instance(MlabSceneModel, ())
scene_y = Instance(MlabSceneModel, ())
scene_z = Instance(MlabSceneModel, ())
# The data source
data_src = Instance(Source)
# The image plane widgets of the 3D scene
ipw_3d_x = Instance(PipelineBase)
ipw_3d_y = Instance(PipelineBase)
ipw_3d_z = Instance(PipelineBase)
# The cursors on each view:
cursors = Dict()
disable_render = Bool
_axis_names = dict(x=0, y=1, z=2)
#---------------------------------------------------------------------------
# Object interface
#---------------------------------------------------------------------------
def __init__(self, **traits):
super(VolumeSlicer, self).__init__(**traits)
# Force the creation of the image_plane_widgets:
self.ipw_3d_x
self.ipw_3d_y
self.ipw_3d_z
#---------------------------------------------------------------------------
# Default values
#---------------------------------------------------------------------------
def _position_default(self):
return 0.5*np.array(self.data.shape)
def _data_src_default(self):
return mlab.pipeline.scalar_field(self.data,
figure=self.scene3d.mayavi_scene,
name='Data',)
def make_ipw_3d(self, axis_name):
ipw = mlab.pipeline.image_plane_widget(self.data_src,
figure=self.scene3d.mayavi_scene,
plane_orientation='%s_axes' % axis_name,
name='Cut %s' % axis_name)
return ipw
def _ipw_3d_x_default(self):
return self.make_ipw_3d('x')
def _ipw_3d_y_default(self):
return self.make_ipw_3d('y')
def _ipw_3d_z_default(self):
return self.make_ipw_3d('z')
#---------------------------------------------------------------------------
# Scene activation callbacks
#---------------------------------------------------------------------------
@on_trait_change('scene3d.activated')
def display_scene3d(self):
outline = mlab.pipeline.outline(self.data_src,
figure=self.scene3d.mayavi_scene,
)
self.scene3d.mlab.view(40, 50)
# Interaction properties can only be changed after the scene
# has been created, and thus the interactor exists
for ipw in (self.ipw_3d_x, self.ipw_3d_y, self.ipw_3d_z):
ipw.ipw.interaction = 0
self.scene3d.scene.background = (0, 0, 0)
# Keep the view always pointing up
self.scene3d.scene.interactor.interactor_style = \
tvtk.InteractorStyleTerrain()
self.update_position()
def make_side_view(self, axis_name):
scene = getattr(self, 'scene_%s' % axis_name)
scene.scene.parallel_projection = True
ipw_3d = getattr(self, 'ipw_3d_%s' % axis_name)
# We create the image_plane_widgets in the side view using a
# VTK dataset pointing to the data on the corresponding
# image_plane_widget in the 3D view (it is returned by
# ipw_3d._get_reslice_output())
side_src = ipw_3d.ipw._get_reslice_output()
ipw = mlab.pipeline.image_plane_widget(
side_src,
plane_orientation='z_axes',
vmin=self.data.min(),
vmax=self.data.max(),
figure=scene.mayavi_scene,
name='Cut view %s' % axis_name,
)
setattr(self, 'ipw_%s' % axis_name, ipw)
# Extract the spacing of the side_src to convert coordinates
# into indices
spacing = side_src.spacing
# Make left-clicking create a crosshair
ipw.ipw.left_button_action = 0
x, y, z = self.position
cursor = mlab.points3d(x, y, z,
mode='axes',
color=(0, 0, 0),
scale_factor=2*max(self.data.shape),
figure=scene.mayavi_scene,
name='Cursor view %s' % axis_name,
)
self.cursors[axis_name] = cursor
# Add a callback on the image plane widget interaction to
# move the others
this_axis_number = self._axis_names[axis_name]
def move_view(obj, evt):
# Disable rendering on all scene
position = list(obj.GetCurrentCursorPosition()*spacing)[:2]
position.insert(this_axis_number, self.position[this_axis_number])
# We need to special case y, as the view has been rotated.
if axis_name is 'y':
position = position[::-1]
self.position = position
ipw.ipw.add_observer('InteractionEvent', move_view)
ipw.ipw.add_observer('StartInteractionEvent', move_view)
# Center the image plane widget
ipw.ipw.slice_position = 0.5*self.data.shape[
self._axis_names[axis_name]]
# 2D interaction: only pan and zoom
scene.scene.interactor.interactor_style = \
tvtk.InteractorStyleImage()
scene.scene.background = (0, 0, 0)
# Some text:
mlab.text(0.01, 0.8, axis_name, width=0.08)
# Choose a view that makes sens
views = dict(x=(0, 0), y=(90, 180), z=(0, 0))
mlab.view(views[axis_name][0],
views[axis_name][1],
focalpoint=0.5*np.array(self.data.shape),
figure=scene.mayavi_scene)
scene.scene.camera.parallel_scale = 0.52*np.mean(self.data.shape)
@on_trait_change('scene_x.activated')
def display_scene_x(self):
return self.make_side_view('x')
@on_trait_change('scene_y.activated')
def display_scene_y(self):
return self.make_side_view('y')
@on_trait_change('scene_z.activated')
def display_scene_z(self):
return self.make_side_view('z')
#---------------------------------------------------------------------------
# Traits callback
#---------------------------------------------------------------------------
@on_trait_change('position')
def update_position(self):
""" Update the position of the cursors on each side view, as well
as the image_plane_widgets in the 3D view.
"""
# First disable rendering in all scenes to avoid unnecessary
# renderings
self.disable_render = True
# For each axis, move image_plane_widget and the cursor in the
# side view
for axis_name, axis_number in self._axis_names.items():
ipw3d = getattr(self, 'ipw_3d_%s' % axis_name)
ipw3d.ipw.slice_position = self.position[axis_number]
# Go from the 3D position, to the 2D coordinates in the
# side view
position2d = list(self.position)
position2d.pop(axis_number)
if axis_name is 'y':
position2d = position2d[::-1]
# Move the cursor
# For the following to work, you need Mayavi 3.4.0, if you
# have a less recent version, use 'x=[position2d[0]]'
self.cursors[axis_name].mlab_source.trait_set(
x=position2d[0], y=position2d[1], z=0)
# Finally re-enable rendering
self.disable_render = False
@on_trait_change('disable_render')
def _render_enable(self):
for scene in (self.scene3d, self.scene_x, self.scene_y,
self.scene_z):
scene.scene.disable_render = self.disable_render
#---------------------------------------------------------------------------
# The layout of the dialog created
#---------------------------------------------------------------------------
view = View(HGroup(
Group(
Item('scene_y',
editor=SceneEditor(scene_class=Scene),
height=250, width=300),
Item('scene_z',
editor=SceneEditor(scene_class=Scene),
height=250, width=300),
show_labels=False,
),
Group(
Item('scene_x',
editor=SceneEditor(scene_class=Scene),
height=250, width=300),
Item('scene3d',
editor=SceneEditor(scene_class=Scene),
height=250, width=300),
show_labels=False,
),
),
resizable=True,
title='Volume Slicer',
)
################################################################################
if __name__ == '__main__':
# Create some data
x, y, z = np.ogrid[-5:5:100j, -5:5:100j, -5:5:100j]
data = np.sin(3*x)/x + 0.05*z**2 + np.cos(3*y)
m = VolumeSlicer(data=data)
m.configure_traits()
