Tesseract test

#include <iostream>
#include <iomanip>
#include <chrono>
#include <thread>
#include <algorithm>
#include <tesseract-4_2/baseapi.h>
#include <leptonica-1_1/allheaders.h>

/* -------------------------------------------------------------------------- */

static void usage()
{
   std::cerr << "Usage : ./testTesseract <traineddata directory> <language> <mode> [pictures]" << std::endl;
   std::cerr << "Modes : Tesseract, LSTM, both" << std::endl;
}

int main(int argc, char *argv[])
{
   if (argc < 4)
   {
      usage();
      return 1;
   }

   std::string trainedDataDir = argv[1];
   std::string language = argv[2];
   std::string mode = argv[3];

   tesseract::OcrEngineMode engineMode;

   if (mode == "Tesseract")
      engineMode = tesseract::OEM_TESSERACT_ONLY;
   else if (mode == "LSTM")
      engineMode = tesseract::OEM_LSTM_ONLY;
   else if (mode == "both")
      engineMode = tesseract::OEM_TESSERACT_LSTM_COMBINED;
   else
   {
      usage();
      std::cerr << "\"" << mode << "\" is not a valid mode" << std::endl;
      return 2;
   }

   tesseract::TessBaseAPI m_ocrApi;
   int res = m_ocrApi.Init(trainedDataDir.c_str(), language.c_str(), engineMode);
   if (res != 0)
      return 3;

   std::cerr << "OCR loaded" << std::endl;

   for (int i = 4; i < argc; i++)
   {
      // Load picture
      PIX* p = pixRead(argv[i]);
      std::cerr << "Picture " << argv[i] << " loaded : "
                << "w = " << std::setw(3) << p->w << ", "
                << "h = " << std::setw(3) << p->h << ", "
                << "d = " << std::setw(2) << p->d << ". ";

      // Perform OCR
      auto beforeOCR = std::chrono::system_clock::now();
      m_ocrApi.SetImage(p);
      m_ocrApi.SetSourceResolution(70);
      const char* result = m_ocrApi.GetUTF8Text();
      auto afterOCR = std::chrono::system_clock::now();

      if (result != nullptr)
      {
         std::string outText = result;
         // Display result
         std::chrono::duration<double> elapsed_seconds = afterOCR - beforeOCR;
         if (outText.back() == '\n')
            outText.pop_back();
         std::replace(outText.begin(), outText.end(), '\n', ' ');
         std::cerr << "Took " << elapsed_seconds.count() << "s, ";
         std::cerr << "decoded : \"" << outText << "\"." << std::endl;
      }
      else
         std::cerr << "<error>" << std::endl;

      pixDestroy(&p);
   }

   m_ocrApi.End();
}

/* -------------------------------------------------------------------------- */