Paraview Java

Julien · May 26, 2023, 11:02am

Hello Everyone,
I am considering using Paraview as a data viewer in a Java project, so in a Java dedicated window (probably a Java Swing JFrame/etc) and I was wondering whether it was possible and if there were a dedicated tutorial about that (at least for a hello world).

I have configured my Paraview build with the VTK Java option, and it indeed created a few *.java files in the …\pv\pv\VTK\Wrapping\Java folder.
But it’s a bit unclear to me whether it’s only a VTK option or a Paraview one too.
When I configured the build the CMake it looked like it made something about both VTK and Paraview, so it looks promising, but I don’t know for sure.

So my questions are:

is there a java Paraview wrapper or is it just the VTK layer?
In python there is the paraview.simple module, and so is there an equivalent in Java by any chance?

Also, I would have thought there might be a *.jar generated but I couldn’t find any (only .java)
=> Is there an official java Paraview Hello World of some sort available?

Thanks in advance!

mwestphal · May 26, 2023, 11:14am

Hi @Julien

I’m afraid Java wrapping of VTK is not usable at ParaView level. I see two ways forward.

pvpython

Use ParaView python bindings as ParaViewWeb does in order to use ParaView in your application. You probably can call on python from Java.

https://kitware.github.io/paraview-docs/latest/python/

Use libf3d java wrapping. F3D is a VTK based 3D viewer that may be what you are looking for if you just want to visualize data. No processing of data possible.

github.com

f3d-app/f3d/blob/master/java/testing/TestJavaBindings.java

import app.f3d.F3D.*;

public class TestJavaBindings {

  static {
    if (System.getProperty("os.name").startsWith("Windows"))
    {
      // On Windows, preload the OpenGL library
      // This ensures the OpenGL used is the one in the working directory if any.
      // In practice, it is used in F3D CI to run the test using Mesa, it's not required for production.
      System.loadLibrary("opengl32");
    }
  }

  public static void main(String[] args) {

    Engine.autoloadPlugins();

    // Always use try-with-resources idiom to ensure the native engine is released
    try (Engine engine = new Engine(Window.Type.NATIVE_OFFSCREEN)) {

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hth

Julien · May 26, 2023, 12:35pm

Well, thank you very much already! I am going to take a look at the two options your are referring to.

I had already guessed I could probably use a python wrapping layer in between but I would have to have a look at the details and see if it would not be too hard to maintain (and possibly a performance trade off, but probably nothing noticeable as it would be just a high level binding anyway)

On the other hand I guess Paraview has an API directly in C++, hasn’t it? (with similar functionalities as the python version, which is probably just calling the C++ API underneath?)
That would mean I could do a (limited) Java binding with JNI (or maybe even JNA over the standards DLL, I don’t know)

Do you confirm it would be easy enough and realistic to build and maintain such JNI binding? (I have already made a JAWT binding of a basic in house 3D engine and it works well in our Java Swing application)
Is there a known C++ good/simple example of an instanciation of a Paraview 3d window you would be aware of? I am going to have a look at that as well.

Thanks!

PS: our program will need a 3D viewer with some features as slice planes, animations and so on.

mwestphal · May 26, 2023, 12:40pm

Yes

Do you confirm it would be easy enough and realistic to build and maintain such JNI binding?

This will be a very hard work and unless it is automated and part of ParaView, a nightmare to maintain.

Is there a known C++ good/simple example of an instanciation of a Paraview 3d window you would be aware of?

I’m afraid not.

Julien · May 26, 2023, 12:46pm

Oh, neat, now this looks promising! …

… shucks!

All right!

So, probably python binding
Still, I am wondering what the python binding implementation looks like, as I imagine it could be used as a model to generate a java version look alike … I will have a quick look too, just in case.

Thank you very much!