BSpline.cpp

Describe a curve thanks to a BSpline.

/*
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2025 by Inria. All rights reserved.
 *
 * This software is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * See the file LICENSE.txt at the root directory of this source
 * distribution for additional information about the GNU GPL.
 *
 * For using ViSP with software that can not be combined with the GNU
 * GPL, please contact Inria about acquiring a ViSP Professional
 * Edition License.
 *
 * See https://visp.inria.fr for more information.
 *
 * This software was developed at:
 * Inria Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
 * 35042 Rennes Cedex
 * France
 *
 * If you have questions regarding the use of this file, please contact
 * Inria at visp@inria.fr
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Description:
 * Example of a B-Spline curve.
 */


 
#include <visp3/core/vpConfig.h>
#include <visp3/core/vpDebug.h>
 
#include <visp3/core/vpBSpline.h>
 
#include <visp3/core/vpDisplay.h>
#include <visp3/core/vpImage.h>
#include <visp3/core/vpImagePoint.h>
#include <visp3/io/vpImageIo.h>
#ifdef VISP_HAVE_MODULE_GUI
#include <visp3/gui/vpDisplayFactory.h>
#endif
 
#include <cstdlib>
#include <stdlib.h>
#include <visp3/core/vpIoTools.h>
#include <visp3/io/vpParseArgv.h>
 
#if defined(VISP_HAVE_DISPLAY)
 
 // List of allowed command line options
#define GETOPTARGS "cdh"
 
#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif
 
void usage(const char *name, const char *badparam);
bool getOptions(int argc, const char **argv, bool &click_allowed, bool &display);

void usage(const char *name, const char *badparam)
{
  fprintf(stdout, "\n\
Describe a curve thanks to a BSpline.\n\
\n\
SYNOPSIS\n\
  %s [-c] [-d] [-h]\n",
          name);
 
  fprintf(stdout, "\n\
OPTIONS:                                               Default\n\
  -c\n\
     Disable the mouse click. Useful to automate the \n\
     execution of this program without human intervention.\n\
\n\
  -d \n\
     Turn off the display.\n\
\n\
  -h\n\
     Print the help.\n");
 
  if (badparam)
    fprintf(stdout, "\nERROR: Bad parameter [%s]\n", badparam);
}

bool getOptions(int argc, const char **argv, bool &click_allowed, bool &display)
{
  const char *optarg_;
  int c;
  while ((c = vpParseArgv::parse(argc, argv, GETOPTARGS, &optarg_)) > 1) {
 
    switch (c) {
    case 'c':
      click_allowed = false;
      break;
    case 'd':
      display = false;
      break;
    case 'h':
      usage(argv[0], nullptr);
      return false;
 
    default:
      usage(argv[0], optarg_);
      return false;
    }
  }
 
  if ((c == 1) || (c == -1)) {
    // standalone param or error
    usage(argv[0], nullptr);
    std::cerr << "ERROR: " << std::endl;
    std::cerr << "  Bad argument " << optarg_ << std::endl << std::endl;
    return false;
  }
 
  return true;
}
 
int main(int argc, const char **argv)
{
  // We declare the display variable to be able to free it in the catch block if needed.
#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
  std::shared_ptr<vpDisplay> display;
#else
  vpDisplay *display = nullptr;
#endif
  try {
    bool opt_click_allowed = true;
    bool opt_display = true;
 
    // Read the command line options
    if (getOptions(argc, argv, opt_click_allowed, opt_display) == false) {
      return EXIT_FAILURE;
    }
 
    // Declare an image, this is a gray level image (unsigned char)
    // it size is not defined yet, it will be defined when the image will
    // read on the disk
    vpImage<unsigned char> I(540, 480);
 
    // We open a window using either X11, GTK or GDI.
#if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_11)
    display = vpDisplayFactory::createDisplay();
#else
    display = vpDisplayFactory::allocateDisplay();
#endif
 
    if (opt_display) {
      // Display size is automatically defined by the image (I) size
      display->init(I, 100, 100, "Display image");
      vpDisplay::display(I);
      vpDisplay::flush(I);
    }
 
    vpBSpline bSpline;
    std::list<double> knots;
    knots.push_back(0);
    knots.push_back(0);
    knots.push_back(0);
    knots.push_back(1);
    knots.push_back(2);
    knots.push_back(3);
    knots.push_back(4);
    knots.push_back(4);
    knots.push_back(5);
    knots.push_back(5);
    knots.push_back(5);
 
    std::list<vpImagePoint> controlPoints;
    vpImagePoint pt;
    pt.set_ij(50, 300);
    controlPoints.push_back(pt);
    pt.set_ij(100, 130);
    controlPoints.push_back(pt);
    pt.set_ij(150, 400);
    controlPoints.push_back(pt);
    pt.set_ij(200, 370);
    controlPoints.push_back(pt);
    pt.set_ij(250, 120);
    controlPoints.push_back(pt);
    pt.set_ij(300, 250);
    controlPoints.push_back(pt);
    pt.set_ij(350, 200);
    controlPoints.push_back(pt);
    pt.set_ij(400, 300);
    controlPoints.push_back(pt);
 
    bSpline.set_p(2);
    bSpline.set_knots(knots);
    bSpline.set_controlPoints(controlPoints);
 
    std::cout << "The parameters are :" << std::endl;
    std::cout << "p : " << bSpline.get_p() << std::endl;
    std::cout << "" << std::endl;
    std::cout << "The knot vector :" << std::endl;
    std::list<double> knots_cur;
    bSpline.get_knots(knots_cur);
    unsigned int i_display = 0;
    for (std::list<double>::const_iterator it = knots_cur.begin(); it != knots_cur.end(); ++it, ++i_display) {
      std::cout << i_display << " ---> " << *it << std::endl;
    }
    std::cout << "The control points are :" << std::endl;
    std::list<vpImagePoint> controlPoints_cur;
    bSpline.get_controlPoints(controlPoints_cur);
    i_display = 0;
    for (std::list<vpImagePoint>::const_iterator it = controlPoints_cur.begin(); it != controlPoints_cur.end();
         ++it, ++i_display) {
      std::cout << i_display << " ---> " << *it << std::endl;
    }
 
    unsigned int i = bSpline.findSpan(5 / 2.0);
    std::cout << "The knot interval number for the value u = 5/2 is : " << i << std::endl;
 
    vpBasisFunction *N = nullptr;
    N = bSpline.computeBasisFuns(5 / 2.0);
    std::cout << "The nonvanishing basis functions N(u=5/2) are :" << std::endl;
    for (unsigned int j = 0; j < bSpline.get_p() + 1; j++)
      std::cout << N[j].value << std::endl;
 
    vpBasisFunction **N2 = nullptr;
    N2 = bSpline.computeDersBasisFuns(5 / 2.0, 2);
    std::cout << "The first derivatives of the basis functions N'(u=5/2) are :" << std::endl;
    for (unsigned int j = 0; j < bSpline.get_p() + 1; j++)
      std::cout << N2[1][j].value << std::endl;
 
    std::cout << "The second derivatives of the basis functions N''(u=5/2) are :" << std::endl;
    for (unsigned int j = 0; j < bSpline.get_p() + 1; j++)
      std::cout << N2[2][j].value << std::endl;
 
    if (opt_display && opt_click_allowed) {
      double u = 0.0;
      while (u <= 5) {
        pt = bSpline.computeCurvePoint(u);
        vpDisplay::displayCross(I, pt, 4, vpColor::red);
        u += 0.01;
      }
      for (std::list<vpImagePoint>::const_iterator it = controlPoints.begin(); it != controlPoints.end(); ++it) {
        vpDisplay::displayCross(I, *it, 4, vpColor::green);
      }
      vpDisplay::flush(I);
      vpDisplay::getClick(I);
    }
 
    if (N != nullptr)
      delete[] N;
    if (N2 != nullptr) {
      for (unsigned int j = 0; j <= 2; j++)
        delete[] N2[j];
      delete[] N2;
    }
 
#if (VISP_CXX_STANDARD < VISP_CXX_STANDARD_11)
    if (display != nullptr) {
      delete display;
    }
#endif
    return EXIT_SUCCESS;
  }
  catch (const vpException &e) {
    std::cout << "Catch an exception: " << e << std::endl;
#if (VISP_CXX_STANDARD < VISP_CXX_STANDARD_11)
    if (display != nullptr) {
      delete display;
    }
#endif
    return EXIT_FAILURE;
  }
}
 
#else
int main()
{
  std::cout
    << "You do not have X11, GTK, or OpenCV, or GDI (Graphical Device Interface) functionalities to display images..."
    << std::endl;
  std::cout << "Tip if you are on a unix-like system:" << std::endl;
  std::cout << "- Install X11, configure again ViSP using cmake and build again this example" << std::endl;
  std::cout << "Tip if you are on a windows-like system:" << std::endl;
  std::cout << "- Install GDI, configure again ViSP using cmake and build again this example" << std::endl;
  return EXIT_SUCCESS;
}
#endif