remove using json=nlohmann::json from header files to avoid pollution

modules/core/include/visp3/core/vpCannyEdgeDetection.h

@@ -43,7 +43,6 @@
 // 3rd parties include
 #ifdef VISP_HAVE_NLOHMANN_JSON
 #include <nlohmann/json.hpp>
-using json = nlohmann::json; //! json namespace shortcut
 #endif
 
 class VISP_EXPORT vpCannyEdgeDetection
@@ -213,7 +212,7 @@ class VISP_EXPORT vpCannyEdgeDetection
    * \param[in] j : The JSON object, resulting from the parsing of a JSON file.
    * \param[out] detector : The detector that will be initialized from the JSON data.
    */
-  friend inline void from_json(const json &j, vpCannyEdgeDetection &detector)
+  friend inline void from_json(const nlohmann::json &j, vpCannyEdgeDetection &detector)
   {
     std::string filteringAndGradientName = vpImageFilter::vpCannyFilteringAndGradientTypeToString(detector.m_filteringAndGradientType);
     filteringAndGradientName = j.value("filteringAndGradientType", filteringAndGradientName);
@@ -233,10 +232,10 @@ class VISP_EXPORT vpCannyEdgeDetection
    * \param[out] j : A JSON parser object.
    * \param[in] detector : The vpCannyEdgeDetection object that must be parsed into JSON format.
    */
-  friend inline void to_json(json &j, const vpCannyEdgeDetection &detector)
+  friend inline void to_json(nlohmann::json &j, const vpCannyEdgeDetection &detector)
   {
     std::string filteringAndGradientName = vpImageFilter::vpCannyFilteringAndGradientTypeToString(detector.m_filteringAndGradientType);
-    j = json {
+    j = nlohmann::json {
             {"filteringAndGradientType", filteringAndGradientName},
             {"gaussianSize", detector.m_gaussianKernelSize},
             {"gaussianStdev", detector.m_gaussianStdev},

modules/core/src/image/vpCannyEdgeDetection.cpp

@@ -91,6 +91,9 @@ vpCannyEdgeDetection::vpCannyEdgeDetection(const int &gaussianKernelSize, const
 }
 
 #ifdef VISP_HAVE_NLOHMANN_JSON
+
+using json = nlohmann::json;
+
 vpCannyEdgeDetection::vpCannyEdgeDetection(const std::string &jsonPath)
 {
   initFromJSON(jsonPath);

modules/detection/include/visp3/detection/vpDetectorDNNOpenCV.h

@@ -54,7 +54,6 @@
 #include <optional>
 #ifdef VISP_HAVE_NLOHMANN_JSON
 #include <nlohmann/json.hpp>
-using json = nlohmann::json; //! json namespace shortcut
 #endif
 
 /*!
@@ -201,7 +200,7 @@ class VISP_EXPORT vpDetectorDNNOpenCV
      * \param j The JSON object, resulting from the parsing of a JSON file.
      * \param config The configuration of the network, that will be initialized from the JSON data.
      */
-    friend inline void from_json(const json &j, NetConfig &config)
+    friend inline void from_json(const nlohmann::json &j, NetConfig &config)
     {
       config.m_confThreshold = j.value("confidenceThreshold", config.m_confThreshold);
       if (config.m_confThreshold <= 0) {
@@ -241,11 +240,11 @@ class VISP_EXPORT vpDetectorDNNOpenCV
      * \param j A JSON parser object.
      * \param config The vpDetectorDNNOpenCV::NetConfig that must be parsed into JSON format.
      */
-    friend inline void to_json(json &j, const NetConfig &config)
+    friend inline void to_json(nlohmann::json &j, const NetConfig &config)
     {
       std::pair<unsigned int, unsigned int> resolution = { config.m_inputSize.width, config.m_inputSize.height };
       std::vector<double> v_mean = { config.m_mean[0], config.m_mean[1], config.m_mean[2] };
-      j = json {
+      j = nlohmann::json {
         {"confidenceThreshold", config.m_confThreshold  } ,
         {"nmsThreshold"       , config.m_nmsThreshold   } ,
         {"filterSizeRatio"    , config.m_filterSizeRatio} ,
@@ -515,7 +514,7 @@ class VISP_EXPORT vpDetectorDNNOpenCV
    * \param j The JSON object, resulting from the parsing of a JSON file.
    * \param network The network, that will be initialized from the JSON data.
    */
-  friend inline void from_json(const json &j, vpDetectorDNNOpenCV &network)
+  friend inline void from_json(const nlohmann::json &j, vpDetectorDNNOpenCV &network)
   {
     network.m_netConfig = j.value("networkSettings", network.m_netConfig);
   }
@@ -526,9 +525,9 @@ class VISP_EXPORT vpDetectorDNNOpenCV
    * \param j The JSON parser.
    * \param network  The network we want to parse the configuration.
    */
-  friend inline void to_json(json &j, const vpDetectorDNNOpenCV &network)
+  friend inline void to_json(nlohmann::json &j, const vpDetectorDNNOpenCV &network)
   {
-    j = json {
+    j = nlohmann::json {
       {"networkSettings", network.m_netConfig}
     };
   }

modules/detection/src/dnn/vpDetectorDNNOpenCV.cpp

@@ -170,6 +170,9 @@ vpDetectorDNNOpenCV::vpDetectorDNNOpenCV(const NetConfig &config, const DNNResul
 }
 
 #ifdef VISP_HAVE_NLOHMANN_JSON
+
+using json = nlohmann::json;
+
 /**
  * \brief Construct a new vpDetectorDNNOpenCV object from a JSON file and a potential parsing method.
  *

modules/imgproc/include/visp3/imgproc/vpCircleHoughTransform.h

@@ -45,7 +45,6 @@
 // 3rd parties inclue
 #ifdef VISP_HAVE_NLOHMANN_JSON
 #include <nlohmann/json.hpp>
-using json = nlohmann::json;
 #endif
 
 #if (VISP_CXX_STANDARD >= VISP_CXX_STANDARD_17)
@@ -496,6 +495,8 @@ class VISP_EXPORT vpCircleHoughTransform
    */
     inline static vpCircleHoughTransformParameters createFromJSON(const std::string &jsonFile)
     {
+      using json = nlohmann::json;
+
       std::ifstream file(jsonFile);
       if (!file.good()) {
         std::stringstream ss;
@@ -528,6 +529,7 @@ class VISP_EXPORT vpCircleHoughTransform
      */
     inline void saveConfigurationInJSON(const std::string &jsonPath) const
     {
+      using json = nlohmann::json;
       std::ofstream file(jsonPath);
       const json j = *this;
       file << j.dump(4);
@@ -541,7 +543,7 @@ class VISP_EXPORT vpCircleHoughTransform
      * \param[in] j : The JSON object, resulting from the parsing of a JSON file.
      * \param[out] params : The circle Hough transform parameters that will be initialized from the JSON data.
      */
-    friend inline void from_json(const json &j, vpCircleHoughTransformParameters &params)
+    friend inline void from_json(const nlohmann::json &j, vpCircleHoughTransformParameters &params)
     {
       std::string filteringAndGradientName = vpImageFilter::vpCannyFilteringAndGradientTypeToString(params.m_filteringAndGradientType);
       filteringAndGradientName = j.value("filteringAndGradientType", filteringAndGradientName);
@@ -619,11 +621,11 @@ class VISP_EXPORT vpCircleHoughTransform
      * \param[out] j : A JSON parser object.
      * \param[in] params : The circle Hough transform parameters that will be serialized in the json object.
      */
-    friend inline void to_json(json &j, const vpCircleHoughTransformParameters &params)
+    friend inline void to_json(nlohmann::json &j, const vpCircleHoughTransformParameters &params)
     {
       std::pair<unsigned int, unsigned int> radiusLimits = { params.m_minRadius, params.m_maxRadius };
 
-      j = json {
+      j = nlohmann::json {
           {"filteringAndGradientType", vpImageFilter::vpCannyFilteringAndGradientTypeToString(params.m_filteringAndGradientType)},
           {"gaussianKernelSize", params.m_gaussianKernelSize},
           {"gaussianStdev", params.m_gaussianStdev},
@@ -760,7 +762,7 @@ class VISP_EXPORT vpCircleHoughTransform
    * \param[in] j The JSON object, resulting from the parsing of a JSON file.
    * \param[out] detector The detector, that will be initialized from the JSON data.
    */
-  friend inline void from_json(const json &j, vpCircleHoughTransform &detector)
+  friend inline void from_json(const nlohmann::json &j, vpCircleHoughTransform &detector)
   {
     detector.m_algoParams = j;
   }
@@ -771,7 +773,7 @@ class VISP_EXPORT vpCircleHoughTransform
    * \param[out] j A JSON parser object.
    * \param[in] detector The vpCircleHoughTransform that must be parsed into JSON format.
    */
-  friend inline void to_json(json &j, const vpCircleHoughTransform &detector)
+  friend inline void to_json(nlohmann::json &j, const vpCircleHoughTransform &detector)
   {
     j = detector.m_algoParams;
   }

modules/imgproc/src/vpCircleHoughTransform.cpp

@@ -123,6 +123,8 @@ vpCircleHoughTransform::~vpCircleHoughTransform()
 { }
 
 #ifdef VISP_HAVE_NLOHMANN_JSON
+using json = nlohmann::json;
+
 vpCircleHoughTransform::vpCircleHoughTransform(const std::string &jsonPath)
 {
   initFromJSON(jsonPath);