imageDiskRW.cpp

Reading and writting of PPM image using vpImageIo class.

Example of exception handling the exception : read an image that does not exist, write in a directory that does no exist

/****************************************************************************
 *
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2023 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:
 * Reading and writting images on the disk.
 *
*****************************************************************************/
 
#include <stdio.h>
#include <stdlib.h>
#include <visp3/core/vpConfig.h>
#include <visp3/core/vpDebug.h>
#include <visp3/core/vpImage.h>
#include <visp3/core/vpIoTools.h>
#include <visp3/io/vpImageIo.h>
#include <visp3/io/vpParseArgv.h>
  // List of allowed command line options
#define GETOPTARGS "i:o:h"
 
#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif
 
void usage(const char *name, const char *badparam, std::string ipath, std::string opath, std::string user)
{
  fprintf(stdout, "\n\
Read and write PGM images on the disk. Also test exceptions.\n\
\n\
SYNOPSIS\n\
  %s [-i <input image path>] [-o <output image path>]\n\
     [-h]\n\
",
name);
 
  fprintf(stdout, "\n\
OPTIONS:                                               Default\n\
  -i <input image path>                                %s\n\
     Set image input path.\n\
     From this path read \"Klimt/Klimt.pgm\"\n\
     image.\n\
     Setting the VISP_INPUT_IMAGE_PATH environment\n\
     variable produces the same behaviour than using\n\
     this option.\n\
\n\
  -o <output image path>                               %s\n\
     Set image output path.\n\
     From this directory, creates the \"%s\"\n\
     subdirectory depending on the username, where \n\
     Klimt_grey.pgm output image is written.\n\
\n\
  -h\n\
     Print the help.\n\n",
          ipath.c_str(), opath.c_str(), user.c_str());
 
  if (badparam) {
    fprintf(stderr, "ERROR: \n");
    fprintf(stderr, "\nBad parameter [%s]\n", badparam);
  }
}
bool getOptions(int argc, const char **argv, std::string &ipath, std::string &opath, const std::string &user)
{
  const char *optarg_;
  int c;
  while ((c = vpParseArgv::parse(argc, argv, GETOPTARGS, &optarg_)) > 1) {
 
    switch (c) {
    case 'i':
      ipath = optarg_;
      break;
    case 'o':
      opath = optarg_;
      break;
    case 'h':
      usage(argv[0], nullptr, ipath, opath, user);
      return false;
      break;
 
    default:
      usage(argv[0], optarg_, ipath, opath, user);
      return false;
      break;
    }
  }
 
  if ((c == 1) || (c == -1)) {
    // standalone param or error
    usage(argv[0], nullptr, ipath, opath, user);
    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)
{
  try {
    std::string env_ipath;
    std::string opt_ipath;
    std::string opt_opath;
    std::string ipath;
    std::string opath;
    std::string filename;
    std::string username;
 
    std::cout << "-------------------------------------------------------" << std::endl;
    std::cout << "  imageDiskRW.cpp" << std::endl << std::endl;
 
    std::cout << "  reading and writting of PPM image" << std::endl;
    std::cout << "  read an image that does not exist" << std::endl;
    std::cout << "  write in a directory that does no exist" << std::endl;
    std::cout << "-------------------------------------------------------" << std::endl;
    std::cout << std::endl;
 
    // Get the visp-images-data package path or VISP_INPUT_IMAGE_PATH
    // environment variable value
    env_ipath = vpIoTools::getViSPImagesDataPath();
 
    // Set the default input path
    if (!env_ipath.empty())
      ipath = env_ipath;
 
    // Set the default output path
#if !defined(_WIN32) && (defined(__unix__) || defined(__unix) || (defined(__APPLE__) && defined(__MACH__))) // UNIX
    opt_opath = "/tmp";
#elif defined(_WIN32)
    opt_opath = "C:\\temp";
#endif
 
    // Get the user login name
    vpIoTools::getUserName(username);
 
    // Read the command line options
    if (getOptions(argc, argv, opt_ipath, opt_opath, username) == false) {
      return EXIT_SUCCESS;
    }
 
    // Get the option values
    if (!opt_ipath.empty())
      ipath = opt_ipath;
    if (!opt_opath.empty())
      opath = opt_opath;
 
    // Append to the output path string, the login name of the user
    std::string dirname = vpIoTools::createFilePath(opath, username);
 
    // Test if the output path exist. If no try to create it
    if (vpIoTools::checkDirectory(dirname) == false) {
      try {
        // Create the dirname
        vpIoTools::makeDirectory(dirname);
      }
      catch (...) {
        usage(argv[0], nullptr, ipath, opath, username);
        std::cerr << std::endl << "ERROR:" << std::endl;
        std::cerr << "  Cannot create " << dirname << std::endl;
        std::cerr << "  Check your -o " << opath << " option " << std::endl;
        return EXIT_FAILURE;
      }
    }
 
    // Compare ipath and env_ipath. If they differ, we take into account
    // the input path coming from the command line option
    if (!opt_ipath.empty() && !env_ipath.empty()) {
      if (ipath != env_ipath) {
        std::cout << std::endl << "WARNING: " << std::endl;
        std::cout << "  Since -i <visp image path=" << ipath << "> "
          << "  is different from VISP_IMAGE_PATH=" << env_ipath << std::endl
          << "  we skip the environment variable." << std::endl;
      }
    }
 
    // Test if an input path is set
    if (opt_ipath.empty() && env_ipath.empty()) {
      usage(argv[0], nullptr, ipath, opath, username);
      std::cerr << std::endl << "ERROR:" << std::endl;
      std::cerr << "  Use -i <visp image path> option or set VISP_INPUT_IMAGE_PATH " << std::endl
        << "  environment variable to specify the location of the " << std::endl
        << "  image path where test images are located." << std::endl
        << std::endl;
      return EXIT_SUCCESS;
    }
 
 
    // First we wanted to have gray level image (8bits)
    // vpImage is a template class you can declare vpImage of ...
    // everything...
    vpImage<unsigned char> I;
 
    // Although I is a gray level image you can read and write
    // color image. Obviously the color will be translated as a gray level
 
    filename = vpIoTools::createFilePath(ipath, "Klimt/Klimt.ppm");
    vpImageIo::read(I, filename);
 
    filename = vpIoTools::createFilePath(dirname, "IoPPM.Klimt_char.ppm");
    vpImageIo::write(I, filename);
 
    // test io error
    // if the image you want to read on the disk does not exist
    // an exception is thrown
    // Try to load a non existing image
    try {
      filename = vpIoTools::createFilePath(ipath, "image-that-does-not-exist.ppm");
      vpImageIo::read(I, filename);
    }
    catch (const vpException &e) {
      std::cout << "Catch an expected exception: " << e << std::endl;
    }
 
    // same thing if you to write in a directory that does not exist
    // or where you are not allowd to write.
    try {
      filename = vpIoTools::createFilePath(dirname, "directory-that-does-not-exist/Klimt.ppm");
      vpImageIo::write(I, filename);
    }
    catch (const vpException &e) {
      std::cout << "Catch an expected exception: " << e << std::endl;
    }
 
    std::cout << "----------------------------------------------------" << std::endl;
 
    // Let's consider that the image is now a color image (32 bits RGBa)
    vpImage<vpRGBa> Irgba;
 
    // read write unsigned char ppm image.
 
    // Load a color image from the disk
    filename = vpIoTools::createFilePath(ipath, "Klimt/Klimt.ppm");
    vpImageIo::read(Irgba, filename);
 
    // Write the content of the color image on the disk
    filename = vpIoTools::createFilePath(dirname, "IoPGM.Klimt_rgba.ppm");
    vpImageIo::write(Irgba, filename);
 
    // test io error
    try {
      filename = vpIoTools::createFilePath(ipath, "image-that-does-not-exist.ppm");
      vpImageIo::read(Irgba, filename);
    }
    catch (const vpException &e) {
      std::cout << "Catch an expected exception: " << e << std::endl;
    }
 
    // test io error
    try {
      filename = vpIoTools::createFilePath(dirname, "directory-that-does-not-exist/Klimt.ppm");
      vpImageIo::write(Irgba, filename);
    }
    catch (const vpException &e) {
      std::cout << "Catch an expected exception: " << e << std::endl;
    }
    return EXIT_SUCCESS;
  }
  catch (const vpException &e) {
    std::cout << "Catch an unexpected exception: " << e << std::endl;
    return EXIT_FAILURE;
  }
}