This is an example script that demonstrates using the new OpenCVBehaviour in NatCam Professional 1.6.

DrawLine.cs

using UnityEngine;
using NatCamU.Core;
using NatCamU.Professional;
using OpenCVForUnity;

public class DrawLine : OpenCVBehaviour {
    
    public override void OnMatrix () {
        // Draw a diagonal line on our image
        Imgproc.line(matrix, new Point(0, 0), new Point(matrix.cols(), matrix.rows()), new Scalar(255, 0, 0, 255), 4);
        // Display it
        preview.texture = texture;
    }
}