generated via:
cd $VTKSRC
perl Utilities/Doxygen/doc_header2doxygen.pl --to ~/tmp/vtkheaders .
cp -r ~/tmp/vtkheaders/* .

move to entirely this style:
/**
 * something
*/
meanwhile, avoid tabs and end of line whitespace and cut down
on excessive doxygen groups resulting from multiline but
single item declarations

keep it around though, will be handy for other projects

The current dependency relationship in vtk is unclear and misleading.
This MR tries to rewrite them based on header files inclusion of headers
and source files in each module. Corner cases are considered and
modules are sorted in alphabetical order to facilitate future reference.
See details in my gitlab python based script project. In future we can continue
using this script to clean the VTK Dependency easily from
time to time.

One of the VTK dashboards had problems evaluating PYTHON_VERSION,
so stick with PYTHON_MAJOR_VERSION and PYTHON_MINOR_VERSION instead.
Also, change SEND_ERROR to FATAL_ERROR.

We will be removing support for Python 2.6 and Python 3.2 in the near
future, so add deprecation warnings for these.  For older versions of
Python, generate an error.  This deprecation is due in part to the
fact that WebPython now requires Python 2.7 or 3.3+.

There wasn't much left.

Notably, don't #define vtkstd at all anymore.

This reverts commit 772cc086.

Needs more work to build with VTK_KITS_ENABLED and to build
with ParaView.

vtk(.*)\(const vtk\1&\);\s*//\s*Not implemented[\.]*
to
vtk\1(const vtk\1\&) VTK_DELETE_FUNCTION;

vtk(.*)\(const vtk\1 &\);\s*//\s*Not implemented[\.]*
to
vtk\1(const vtk\1 \&) VTK_DELETE_FUNCTION;

vtk(.*)\( const vtk\1 & \);\s*//\s*Not implemented[\.]*
to
vtk\1( const vtk\1 \& ) VTK_DELETE_FUNCTION;

vtk(.*)\( const vtk\1& \);\s*//\s*Not implemented[\.]*
to
vtk\1( const vtk\1\& ) VTK_DELETE_FUNCTION;

vtk(.*) \(const vtk\1&\);\s*//\s*Not implemented[\.]*
to
vtk\1 (const vtk\1\&) VTK_DELETE_FUNCTION;

(operator\s*=.*);\s*//\s*Not\s*implemented[\.]*
to
\1 VTK_DELETE_FUNCTION;

After that, this finds basically nothing:

operator.*implemented

then manually reverted changed files in VPIC and KWSys folders.

These files will eventually need vtkConfigure.h
for eventual VTK_DELETE_FUNCTION usage.

Making the code a little less obfuscated.

Even though this utility is not designed to convert K&R braces to Allman
braces, it should indent their closing braces the same way.

This fixes some tricky issues with how VTK uses macros, specifically the
use of code blocks within the argument of vtkTemplateMacro(), and it also
tweaks the handling of case labels (yet again).

Any flow control keyword (if, while, etc.) should increase the indent
level, even if not followed by the opening brace that VTK style requires.
I've also created a short exception list, so that vtkParse.tab.c and
lex.yy.c (which are generated files) are not re-indented.

If this option is used, then vtk_reindent_code will print a warning
for each file with incorrect brace indentation.  It will also print
the line numbers for the incorrect braces.

Six files in the VTK source required vtk_reindent_code.py to be called
twice in order for the indentation to be corrected (all other files only
required it to be called once).  The problem with those six files was
nested blocks where all source lines between the beginning of the outer
block and the beginning of the inner block were comments.  There is
probably a way to fix the script so that it properly deals with this
situation, but simply re-processing the file until no futher changes
occur is a robust solution that gives the correct result.

Headers installed by the Qt and QtOpenGL modules in GUISupport use this
header naming convention. This allows the script to identify that including
QVTKWidget.h means you depend on the vtkGUISupportQt module, for instance

patch courtesy of Tim Rowley for adding width and height
options to the TimingTest

This is similar to what is already done in ITK and SimpleITK.

The new vtkTargetLinkLibrariesWithDynamicLookup.cmake file is slightly modified copy from ITK (things have been renamed from ITK to VTK). The explanation of what this patch tries to achieve is documented in this file.

A new argument is introduced, called OPTIONAL_PYTHON_LINK. When used, the module will be optionally be linked against libpython. In the module.cmake files, most vtkPython dependencies were moved to COMPILE_DEPENDS, so that libpython is not added to the target_link_libraries() call.

The vtkPython is explicitely linked against the python libraries, as this is a python executable.

Also, the find_package calls for the PythonLibs were made optional when possible.

This fixes the following bug: http://www.vtk.org/Bug/view.php?id=16068

Perl was used to remove all the BTX and ETX markers from the code.
The specific command that was run on all "vtk*.h" files was this:
    perl -0777 -i -pe 's/(\n* *\/\/ *[BE]TX *\n+)+/\n\n/g'

This regex replaces each BTX/ETX line, plus any leading or trailing
blank lines, with a single blank line.

First automatically removed lines with only BTX/ETX
from .h files with the following regexes:

^ *// *BTX\r
^ *// *ETX\r

and replaced occurances with nothing. Committed that, then manually
removed various remaining cases of BTX/ETX, and related comments, and parsing stuff,
then trashed the first commit.

Changed some operator= from returning void to returning *this.

This 10M triangle scene stresses depth peeling implementations to see
how well they perform.

Results (nVidia Quadro 2000M, Release build):

vtkDepthPeelingPass: 1.2 FPS (0.77s first frame, 0.83s subsequent)
vtkDualDepthPeelingPass: 2.5 FPS (0.56s first frame, 0.40s subsequent)

We see a roughly 50% improvement with the new dual algorithm, since
the dual algorithm peels 2 layers per geometry pass.

For reference, simple alpha blending results in 49 FPS, 0.18s first frame,
0.020s subsequent.

Code extracted from:

    https://gitlab.kitware.com/third-party/proj.git

at commit 41bdf05361007f8c5186f3df9944d86bb273ed13 (for/vtk).

This is a python script that changes the Whitesmiths indentation
style to the Allman indentation style that is currently more popular.
This script will only change the brace indentation, it will not change
the code in any other way, so "git blame" results will be mostly
unchanged after re-styling.

Changed some parameters to be by reference,
instead of by value, including some public API.

If the SliceLocation tag was present but empty, the reader would crash.
This fix adds a check.

Reduce opengl2 dependencies in two ways
first move a class that renderingcore depends on from
filterExtraction to FiltersGeneral. FiltersExtraction pulls
in a lot of other modules where FiltersGeneral does not.
FiltersExtraction already depends on filtersGeneral so it
should be backwards compatible.

The second change is a new feature to allow a back implementation
to be required or not. In this case gl2ps was originally required
by OpenGl2 now it is optional. This required adding an option to
the module code to specify when a backend implementation is required.

Find/replace of:

with C++ counterparts.  Changed only vtk*.cxx files.
Didn’t touch .h or .c or any 3rd party.

This resolves linking errors when doing static cross-compile builds
against python with no thread support.

We have not used it in VTK for a long time.