****************************************************************
** WARNING: There is absolutely no warranty for this software **
** package. See the file COPYING for details.                 **
****************************************************************

			    Graphics::VTK 
			    Version  4.0.001
			  	 by 
			    Roberto De Leo
			        and
			    John Cerney
			 j-cerney1@raytheon.com

  What is it?
  -----------
  Graphics::VTK  is a module that allows you to call VTK (Visualization
  ToolKit) functions from a perl script. The Visualization ToolKit is
  an open-source 3D Graphics Visualization library available at
  www.kitware.com.
  
  Graphics::VTK is designed to work similarly to the  TCL bindings
  that come with the stock VTK package. For example, Perl Tk Widgets are provided that 
  interface with VTK, similar to the tcl/tk widget interfaces provided with 
  the stock VTK.


  Prerequisites
  -------------

  You need to install two packages before trying to compile this:
  - the Tk module, that you can get from http://www.cpan.org
  - the VTK library, version 4.0, that is freely available 
    from ftp://public.kitware.com/pub/vtk/vtk4.0
    (Version 4.0 is of VTK is required, not version 3.1, or 3.2. 
    Graphics::VTK 4.0.001 is specifically for VTK version 4.0.)
    
  To test the module, you will need the VTK test data available
  at www.kitware.com. Once you have this data installed, set
  the environment variable VTK_DATA_ROOT to point to the installation
  path of this data. For example, if you extracted the vtk data
  to /home/mydir/vtkdata, set VTK_DATA_ROOT=/home/mydir/vtkdata


  Installation
  ------------

  First of all, you should modify the file VTK.config according to your 
  system. Example files are provided that a known to work with Redhat 7.1,
  Solaris 2.6.1, and win32 (with the mingw compiler on win32). Note
  that the installation process is slightly different from the standard
  perl module compilation because we have to use a C++ compiler. Perl
  modules typically use a C compiler.
  
  Then you can now start the compilation with the standard

  perl makefile.PL
  make
  make test
  make install

  WARNING: during the compilation, consumption of memory arrives to ~200Mb
  so do not try to compile this module if you do not have enough RAM+Swap
  
  Note: As of this release. This package has been successfully built and
  tested on Sun Solaris, Linux (Red Hat 7.1, 7.3), and Windows NT (using mingw32
  compiler).

  Testing
  -------
  
  With the VTK data installed (see Prerequisites section), this package
  is tested by running a set of example scripts that are known to work. 
  See the examples/README file, or the test.pl script itself for a list
  of these scripts. These test scripts are interactive, so you will
  have to view the results and exit-out of each test as they are run.
  
  Example Scripts
  ---------------
  
  The example tcl scripts from the VTK 4.0 distribution have been converted
  to perl and placed in the following directories under the 'examples' dir:
  Annotation, DataManipulation,GUI,  ImageProcessing, IO, Modeling, Rendering,
  Tutorial, VisualizationAlgorithms, VolumeRendering.
  
  Documentation
  -------------

  Detailed documentation of the VTK package is available at the VTK 
  web site at http://www.kitware.com. The documentation included in this 
  package details which object methods are  supported. After
  installing type 'perldoc VTK', or perldoc 'Graphics::VTK::Common', etc,
  to access these docs.


  VTK Versions and Graphics::VTK Versions
  ---------------------------------------
  
  Due to differences between c++ methods of different VTK versions, 
  Graphics::VTK versions are closely tied to a particular VTK version.
  For example, Graphics::VTK 4.0.001 is written to work with VTK 4.0 
  only. Similarly, Graphics::VTK 3.2.001 is written to work with VTK 3.2
  only.
 
  Note that any scripts you write using Graphics::VTK 3.2.001 should
  still work with any new releases (version 3.2.001, or 4.0.001), 
  unless you are using some feature of VTK that has changed between 
  VTK 3.2 and 4.0. 


  Known Issues
  ------------
  Under some conditions, perl/VTK will deadlock (i.e. freeze/hang-up) when
  performing i/o operations using C++ streams. This has been observed for
  the using glibc/gcc on a redhat linux 7.2 platform, where the
  supplied perl was not linked against the pthread library. (libpthread
  doesn't show up when performing a perl -V).
  As a work-around, the LD_PRELOAD environment variable can be set to 
  fix this problem. i.e. before running perl on the command line (or
  in your .bashrc file) type the following:
  export LD_PRELOAD=libpthread.so 
  
  
