This section describes some other useful modules that are released as
part of MayaVi but are not necessarily part of the core MayaVi
module/application. The module
described in the next section. The MayaVi package also contains a
tools. This directory
contains miscellaneous but useful tools that use or are related to
MayaVi. This is described subsequently.
It is very nice to be able to use and experiment with VTK from the
Python interpreter. In order to make this easier I've written a
simple module that uses some of the MayaVi classes. This makes using
VTK from Python very pleasant. The module is called
ivtk which stands for interactive VTK.
ivtk provides the following features.
An easy to use VTK actor viewer that has menus to save the scene, change background, show a help browser, show a pipeline browser etc.
A simple class documentation search tool/browser that lets you search for arbitrary strings in the VTK class documentation and lets you browse the VTK class documentation.
An easy to use GUI to configure VTK objects using the
An integrated picker that can be activated by pressing the p or P keys. This picker functions the same way as the MayaVi picker.
An integrated light configuration kit that can be activated by pressing the l or L keys. This light configuration functions the same way as the MayaVi light kit.
The help browser allows one to search for arbitrary strings in the VTK class documentation. 'and' and 'or' keywords are supported and this makes searching for specific things easier. If a search is successful a list of matching classes is returned. Clicking on a class will pop up a window with the particular class documentation. It is also possible to search for a particular class name. All classes matching the searched name will be shown. The searching is case insensitive.
Here is a sample session that illustrates how
ivtk can be used. A simple cone
example is shown.
>>> from mayavi import ivtk >>> from vtk import * >>> c = vtkConeSource() >>> m = vtkPolyDataMapper() >>> m.SetInput(c.GetOutput()) >>> a = vtkActor() >>> a.SetMapper(m) >>> v = ivtk.create_viewer() # or ivtk.viewer() # this creates the easy to use render window that can be used from # the interpreter. It has several useful menus. >>> v.AddActors(a) # add actor(s) to viewer >>> v.config(c) # pops up a GUI configuration for object. >>> v.doc(c) # pops up class documentation for object. >>> v.help_browser() # pops up a help browser where you can search! >>> v.RemoveActors(a) # remove actor(s) from viewer.
AddActors/RemoveActors method can be passed a
list/tuple or a single actor. All of the passed actors will be
added/removed to the
vtkRenderWindow . The
config method provides an easy to use GUI to
configure the passed VTK object. The viewer also provides menus to
save the rendered scene and also provides a menu to open a VTK
Pipeline browser that can be used to browse the VTK pipeline and
configure objects in it.
Even without creating the actor viewer it is possible to use the help browser and the configure code as shown below.
>>> from mayavi import ivtk >>> d = ivtk.doc_browser() # pops up a standalone searcheable VTK class help browser. >>> from vtk import * >>> c = vtkConeSource() >>> ivtk.doc(c) # pops up class documentation for c >>> ivtk.doc('vtkObject') # class documentation for vtkObject. >>> ivtk.config(c) # configure object with GUI.
The module is fairly well documented and one should look at the module for more information. However, the above information should suffice if one wants to start using the module.
MayaVi has a
tools sub-package that contains
useful modules that use or are related to MayaVi. The following
modules are present currently.
imv module provides Matlab-like one liners
that make it easy to visualize data from the Python interpreter. It
currently provides three useful functions. These are partially
described below. A simple example is also provided below that. The
imv module is well documented so please read
the documentation strings in the module for more details.
surf(x, y, f)
This samples the function or 2D array
y and plots a 3D
Views 2D arrays as a structured points dataset. The view is set to the way we usually think of matrices with (0,0) at the top left of the screen.
Views 2D arrays as a structured points dataset. The data is viewed as
an image. This function is meant to be used with large arrays. For
smaller arrays one should use the more powerful
view() function. The implementation of this
function is a bit of a hack and many of MayaVi's features cannot be
used. For instance you cannot change the lookup table color and
expect the color of the image to change.
sampler(xa, ya, func)
Samples a function (
func) at an array of ordered
points (with equal spacing) and returns an array of scalars as per
VTK's requirements for a structured points data set, i.e. x varying
fastest and y varying next.
Here is a simple example of what can be done with the
>>> from Numeric import * >>> from mayavi.tools import imv >>> # surf example. >>> def f(x, y): ... return sin(x*y)/(x*y) >>> x = arange(-5., 5.05, 0.05) >>> y = arange(-5., 5.05, 0.05) >>> v = imv.surf(x, y, f) >>> # view/viewi example. >>> z1 = fromfunction(lambda i,j:i+j, (128,256)) >>> v1 = imv.view(z1) >>> z2 = fromfunction(lambda i,j:i+j, (512, 512)) >>> v2 = imv.viewi(z2)