[Python-apps-team] Bug#550635: mayavi2: [regression] interpolated scalar coloring results in black surface

[Francesco Poli (t1000)]

Package: mayavi2
Version: 3.3.0-1
Severity: important

Hi!

I've just found out a regression in mayavi2 (I am pretty sure this
didn't use to happen previously).

Steps to reproduce:

  $ mayavi2 -d /usr/share/doc/mayavi2/examples/mayavi/data/heart.vtk

The main window shows up.

 * in the Mayavi pane, click on Add module or filter
 * in the Mayavi object editor pane, double-click on Scalar Cut Plane
 * in the Mayavi Scene 1 pane, click on View along the +X axis

The scalar cut plane is now visible and shows a scalar color map,
which is however blocky and non-smooth, with poorly defined contours.

 * in the Mayavi object editor pane, Actor tab, check
   Interpolate scalars before mapping

Hey!
The scalar cut plane is not completely painted black!
This should *not* happen!

 * look slightly below in the Actor tab, inside the Property frame:
   the Color property is set to black
 * change the Color property from black to white (by moving the third
   slider to the extreme left: BTW, this color chooser widget is really
   terrible, from a usability point of view!)

Hey!
Now the scalar cut plane correctly shows an interpolated scalar
coloring, as desired.


It seems that the Color property's Value (that is to say, the third
coordinate in a HSV color space) determines how much scalar coloring
is performed, when interpolation is enabled: I get the correct
visualization with white Color (Value = 100 %), I get a black surface
without any visible scalar coloring on it with black Color (Value = 0),
while I get a semi-transparent scalar coloring superposed to the black
surface with any other Color (any Value in between).

I am experiencing the same misbehavior with other visualization modules,
such as Custom Grid Plane, Surface, and so forth...
Hence, the issue is not specifically related to Scalar Cut Plane.


What's wrong?

Please forward this bug to upstream, if appropriate.



-- System Information:
Debian Release: squeeze/sid
  APT prefers testing
  APT policy: (800, 'testing'), (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.30-2-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages mayavi2 depends on:
ii  libc6                        2.9-25      GNU C Library: Shared libraries
ii  libjs-jquery                 1.3.3-2     JavaScript library for dynamic web
ii  libvtk5.2                    5.2.1-11    Visualization Toolkit - A high lev
ii  python                       2.5.4-2     An interactive high-level object-o
ii  python-apptools              3.3.0-1     ETS Application Tools
ii  python-central               0.6.11      register and build utility for Pyt
ii  python-configobj             4.5.2-2     a simple but powerful config file 
ii  python-envisagecore          3.1.1-1     Extensible Application Framework
ii  python-envisageplugins       3.1.1-1     Plugins for the Envisage framework
ii  python-numpy                 1:1.3.0-3   Numerical Python adds a fast array
ii  python-pkg-resources         0.6c9-2     Package Discovery and Resource Acc
ii  python-traits                3.2.0-1     Manifest typing and reactive progr
ii  python-traitsgui             3.1.0-1     Traits-capable windowing framework
ii  python-vtk                   5.2.1-11    Python bindings for VTK
ii  python-wxgtk2.8              2.8.7.1-1.1 wxWidgets Cross-platform C++ GUI t
ii  python2.5                    2.5.4-2     An interactive high-level object-o

mayavi2 recommends no packages.

Versions of packages mayavi2 suggests:
pn  ipython                       <none>     (no description available)
pn  python-scipy                  <none>     (no description available)

-- no debconf information