Annotation question about javacpp

[saudet]

We could use some more documentation, obviously :) If you are ever willing to provide some material, please do contribute to the code, the README file or the wiki. Thanks!

So, I'm guessing what you need is the following:

native void foo(@ByRef @Cast("cv::Mat*") Pointer image)

Another way would be to use the Parser, that usually generates an appropriate Java interface by default, but this isn't a straightforward case, so maybe not.

[kmatzen]

Thanks, I think that makes sense to me. I agree that I should use the Parser, but I wanted to understand the code that it generates a bit more before going into that. I did run into an issue where I wasn't easily able to do the same thing by passing a std::vector<cv::Mat*> by reference instead of by pointer. I've included one solution that seems to work. Can you take a look and point out anything that's incorrect or could be done in a better way in this code? I tried using the @StdVector annotation, but couldn't get it to work for my MatPointer.

import org.bytedeco.javacpp.*;
import org.bytedeco.javacpp.annotation.*;

import org.opencv.core.Mat;

@Platform(include={"<vector>", "<opencv2/opencv.hpp>"})
public class cv {
  @Name("std::vector<cv::Mat*>")
  public static class MatVector extends Pointer {
    static { Loader.load(); }
    public MatVector() { allocate(); }
    public MatVector(long n) { allocate(n); }
    public MatVector(Pointer p) { super(p); }
    public MatVector(Mat[] mats) {
      this();

      for (int i = 0; i < mats.length; ++i) {
        Mat mat = mats[i];
        MatPointer newMat = new MatPointer(mat);
        push_back(newMat);
      }
    }
    private native void allocate();
    private native void allocate(long n);
    private native void push_back(MatPointer pointer);
  }

  @Name("cv::Mat")
  public static class MatPointer extends Pointer {
    static { Loader.load(); }
    public MatPointer() { allocate(); }
    public MatPointer(Pointer p) { super(p); }
    public MatPointer(Mat m) {
      this();
      mat = m;
      address = mat.getNativeObjAddr();
      limit = 1;
      capacity = 1;
      position = 0;
    }

    // MatPointer does not take ownership of the native object owned by Mat.
    @NoDeallocator
    private native void allocate();

    // Keep a reference to the Java object to prevent the native object
    // from being deallocated.
    private Mat mat;
  }
}

[saudet]

This is getting complicated... What you're doing seems fine though.

BTW, why not use the opencv module from javacpp-presets? What's missing?

[saudet]

So, I'm assuming everything is working out well enough, but let me know if you still have some issues, thanks!