vpImageIoOpenCV.cpp

/*
 * 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:
 * OpenCV backend for image I/O operations.
 */

 
#include <visp3/core/vpConfig.h>
 
#include "vpImageIoBackend.h"
 
#if defined(VISP_HAVE_OPENCV)
#if (VISP_HAVE_OPENCV_VERSION >= 0x030000) // Require opencv >= 3.0.0
#if defined(HAVE_OPENCV_IMGCODECS)
#include <opencv2/imgcodecs.hpp>
#endif
#else // Require opencv >= 2.4.8
#if defined(HAVE_OPENCV_HIGHGUI) && defined(HAVE_OPENCV_IMGPROC)
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#endif
#endif
#endif
 
#include <visp3/core/vpImageConvert.h>
 
#if defined(VISP_HAVE_OPENCV) && \
    (((VISP_HAVE_OPENCV_VERSION >= 0x030000) && defined(HAVE_OPENCV_IMGCODECS)) || \
     ((VISP_HAVE_OPENCV_VERSION < 0x030000) && defined(HAVE_OPENCV_HIGHGUI) && defined(HAVE_OPENCV_IMGPROC)))
 
BEGIN_VISP_NAMESPACE
void readOpenCV(vpImage<unsigned char> &I, const std::string &filename)
{
#if defined(VISP_HAVE_OPENCV)
#if VISP_HAVE_OPENCV_VERSION >= 0x030200
  int flags = cv::IMREAD_GRAYSCALE | cv::IMREAD_IGNORE_ORIENTATION;
#elif VISP_HAVE_OPENCV_VERSION >= 0x030000
  int flags = cv::IMREAD_GRAYSCALE;
#else
  int flags = CV_LOAD_IMAGE_GRAYSCALE;
#endif
  cv::Mat Ip = cv::imread(filename.c_str(), flags);
  if (!Ip.empty())
    vpImageConvert::convert(Ip, I);
  else
    throw(vpImageException(vpImageException::ioError, "Can't read the image"));
#endif
}

void readOpenCV(vpImage<vpRGBa> &I, const std::string &filename)
{
#if defined(VISP_HAVE_OPENCV)
#if VISP_HAVE_OPENCV_VERSION >= 0x030200
  int flags = cv::IMREAD_COLOR | cv::IMREAD_IGNORE_ORIENTATION;
#elif VISP_HAVE_OPENCV_VERSION >= 0x030000
  int flags = cv::IMREAD_COLOR;
#else
  int flags = CV_LOAD_IMAGE_COLOR;
#endif
  cv::Mat Ip = cv::imread(filename.c_str(), flags);
  if (!Ip.empty())
    vpImageConvert::convert(Ip, I);
  else
    throw(vpImageException(vpImageException::ioError, "Can't read the image"));
#endif
}
 
void readOpenCV(vpImage<float> &I, const std::string &filename)
{
#if defined(VISP_HAVE_OPENCV)
#if VISP_HAVE_OPENCV_VERSION >= 0x030200
  int flags = cv::IMREAD_ANYDEPTH | cv::IMREAD_IGNORE_ORIENTATION;
#elif VISP_HAVE_OPENCV_VERSION >= 0x030000
  int flags = cv::IMREAD_ANYDEPTH;
#else
  int flags = CV_LOAD_IMAGE_ANYDEPTH;
#endif
  cv::Mat Ip = cv::imread(filename.c_str(), flags);
  if (!Ip.empty())
    vpImageConvert::convert(Ip, I);
  else
    throw(vpImageException(vpImageException::ioError, "Can't read the image"));
#else
  throw(vpImageException(vpImageException::ioError, "Can't read the image"));
#endif
}
 
void readOpenCV(vpImage<vpRGBf> &I, const std::string &filename)
{
#if defined(VISP_HAVE_OPENCV)
#if VISP_HAVE_OPENCV_VERSION >= 0x030200
  int flags = cv::IMREAD_COLOR | cv::IMREAD_IGNORE_ORIENTATION;
#elif VISP_HAVE_OPENCV_VERSION >= 0x030000
  int flags = cv::IMREAD_COLOR;
#else
  int flags = CV_LOAD_IMAGE_COLOR;
#endif
  cv::Mat Ip = cv::imread(filename.c_str(), flags);
  if (!Ip.empty())
    vpImageConvert::convert(Ip, I);
  else
    throw(vpImageException(vpImageException::ioError, "Can't read the image"));
#else
  throw(vpImageException(vpImageException::ioError, "Can't read the image"));
#endif
}

void readPNGfromMemOpenCV(const std::vector<unsigned char> &buffer, vpImage<unsigned char> &I)
{
  cv::Mat1b buf(static_cast<int>(buffer.size()), 1, const_cast<unsigned char *>(buffer.data()));
  cv::Mat1b img = cv::imdecode(buf, cv::IMREAD_GRAYSCALE);
  I.resize(img.rows, img.cols);
  std::copy(img.begin(), img.end(), I.bitmap);
}

void readPNGfromMemOpenCV(const std::vector<unsigned char> &buffer, vpImage<vpRGBa> &I_color)
{
  cv::Mat1b buf(static_cast<int>(buffer.size()), 1, const_cast<unsigned char *>(buffer.data()));
  cv::Mat3b img = cv::imdecode(buf, cv::IMREAD_COLOR);
  vpImageConvert::convert(img, I_color);
}

void writeOpenCV(const vpImage<unsigned char> &I, const std::string &filename, int quality)
{
  cv::Mat Ip;
  vpImageConvert::convert(I, Ip);
 
  std::vector<int> compression_params;
  compression_params.push_back(cv::IMWRITE_JPEG_QUALITY);
  compression_params.push_back(quality);
  cv::imwrite(filename.c_str(), Ip, compression_params);
}

void writeOpenCV(const vpImage<vpRGBa> &I, const std::string &filename, int quality)
{
  cv::Mat Ip;
  vpImageConvert::convert(I, Ip);
 
  std::vector<int> compression_params;
  compression_params.push_back(cv::IMWRITE_JPEG_QUALITY);
  compression_params.push_back(quality);
  cv::imwrite(filename.c_str(), Ip, compression_params);
}
 
void writeOpenCV(const vpImage<float> &I, const std::string &filename)
{
  cv::Mat Ip;
  vpImageConvert::convert(I, Ip);
 
  cv::imwrite(filename.c_str(), Ip);
}
 
void writeOpenCV(const vpImage<vpRGBf> &I, const std::string &filename)
{
  cv::Mat Ip;
  vpImageConvert::convert(I, Ip);
 
  cv::imwrite(filename.c_str(), Ip);
}

void writePNGtoMemOpenCV(const vpImage<unsigned char> &I, std::vector<unsigned char> &buffer)
{
  cv::Mat1b img(I.getRows(), I.getCols(), I.bitmap);
  bool result = cv::imencode(".png", img, buffer);
 
  if (!result) {
    std::string message = "Cannot write png to memory";
    throw(vpImageException(vpImageException::ioError, message));
  }
}

void writePNGtoMemOpenCV(const vpImage<vpRGBa> &I_color, std::vector<unsigned char> &buffer, bool saveAlpha)
{
  const int height = I_color.getRows();
  const int width = I_color.getCols();
  const int channels = saveAlpha ? 4 : 3;
 
  if (saveAlpha) {
    cv::Mat4b img(height, width, reinterpret_cast<cv::Vec4b *>(I_color.bitmap));
    // No need to perform RGB to BGR conversion
    bool result = cv::imencode(".png", img, buffer);
 
    if (!result) {
      std::string message = "Cannot write png to memory";
      throw(vpImageException(vpImageException::ioError, message));
    }
  }
  else {
    unsigned char *bitmap = new unsigned char[height * width * channels];
    vpImageConvert::RGBaToRGB(reinterpret_cast<unsigned char *>(I_color.bitmap), bitmap, height*width);
 
    cv::Mat3b img(height, width, reinterpret_cast<cv::Vec3b *>(bitmap));
    // No need to perform RGB to BGR conversion
    bool result = cv::imencode(".png", img, buffer);
    delete[] bitmap;
 
    if (!result) {
      std::string message = "Cannot write png to memory";
      throw(vpImageException(vpImageException::ioError, message));
    }
  }
}
 
END_VISP_NAMESPACE
 
#endif