tessedit.cpp

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/**********************************************************************
 * File:        tessedit.cpp  (Formerly tessedit.c)
 * Description: (Previously) Main program for merge of tess and editor.
 *              Now just code to load the language model and various
 *              engine-specific data files.
 * Author:      Ray Smith
 *
 * (C) Copyright 1992, Hewlett-Packard Ltd.
 ** Licensed under the Apache License, Version 2.0 (the "License");
 ** you may not use this file except in compliance with the License.
 ** You may obtain a copy of the License at
 ** http://www.apache.org/licenses/LICENSE-2.0
 ** Unless required by applicable law or agreed to in writing, software
 ** distributed under the License is distributed on an "AS IS" BASIS,
 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 ** See the License for the specific language governing permissions and
 ** limitations under the License.
 *
 **********************************************************************/
 
// Include automatically generated configuration file if running autoconf.
#ifdef HAVE_CONFIG_H
#  include "config_auto.h"
#endif
 
#include "control.h"
#  include "matchdefs.h"
#include "pageres.h"
#include "params.h"
#include "stopper.h"
#include "tesseractclass.h"
#include "tessvars.h"
#include "tprintf.h"
#ifndef DISABLED_LEGACY_ENGINE
#  include "chop.h"
#  include "intmatcher.h"
#  include "reject.h"
#endif
#ifndef ANDROID_BUILD
#  include "lstmrecognizer.h"
#endif
 
namespace tesseract {
 
// Read a "config" file containing a set of variable, value pairs.
// Searches the standard places: tessdata/configs, tessdata/tessconfigs
// and also accepts a relative or absolute path name.
void Tesseract::read_config_file(const char* filename,
                                 SetParamConstraint constraint) {
  STRING path = datadir;
  path += "configs/";
  path += filename;
  FILE* fp;
  if ((fp = fopen(path.c_str(), "rb")) != nullptr) {
    fclose(fp);
  } else {
    path = datadir;
    path += "tessconfigs/";
    path += filename;
    if ((fp = fopen(path.c_str(), "rb")) != nullptr) {
      fclose(fp);
    } else {
      path = filename;
    }
  }
  ParamUtils::ReadParamsFile(path.c_str(), constraint, this->params());
}
 
// Returns false if a unicharset file for the specified language was not found
// or was invalid.
// This function initializes TessdataManager. After TessdataManager is
// no longer needed, TessdataManager::End() should be called.
//
// This function sets tessedit_oem_mode to the given OcrEngineMode oem, unless
// it is OEM_DEFAULT, in which case the value of the variable will be obtained
// from the language-specific config file (stored in [lang].traineddata), from
// the config files specified on the command line or left as the default
// OEM_TESSERACT_ONLY if none of the configs specify this variable.
bool Tesseract::init_tesseract_lang_data(
    const char* arg0, const char* textbase, const char* language,
    OcrEngineMode oem, char** configs, int configs_size,
    const GenericVector<STRING>* vars_vec,
    const GenericVector<STRING>* vars_values, bool set_only_non_debug_params,
    TessdataManager* mgr) {
  // Set the basename, compute the data directory.
  main_setup(arg0, textbase);
 
  // Set the language data path prefix
  lang = language != nullptr ? language : "eng";
  language_data_path_prefix = datadir;
  language_data_path_prefix += lang;
  language_data_path_prefix += ".";
 
  // Initialize TessdataManager.
  STRING tessdata_path = language_data_path_prefix + kTrainedDataSuffix;
  if (!mgr->is_loaded() && !mgr->Init(tessdata_path.c_str())) {
    tprintf("Error opening data file %s\n", tessdata_path.c_str());
    tprintf(
        "Please make sure the TESSDATA_PREFIX environment variable is set"
        " to your \"tessdata\" directory.\n");
    return false;
  }
#ifndef DISABLED_LEGACY_ENGINE
  if (oem == OEM_DEFAULT) {
    // Set the engine mode from availability, which can then be overridden by
    // the config file when we read it below.
    if (!mgr->IsLSTMAvailable()) {
      tessedit_ocr_engine_mode.set_value(OEM_TESSERACT_ONLY);
    } else if (!mgr->IsBaseAvailable()) {
      tessedit_ocr_engine_mode.set_value(OEM_LSTM_ONLY);
    } else {
      tessedit_ocr_engine_mode.set_value(OEM_TESSERACT_LSTM_COMBINED);
    }
  }
#endif  // ndef DISABLED_LEGACY_ENGINE
 
  // If a language specific config file (lang.config) exists, load it in.
  TFile fp;
  if (mgr->GetComponent(TESSDATA_LANG_CONFIG, &fp)) {
    ParamUtils::ReadParamsFromFp(SET_PARAM_CONSTRAINT_NONE, &fp,
                                 this->params());
  }
 
  SetParamConstraint set_params_constraint =
      set_only_non_debug_params ? SET_PARAM_CONSTRAINT_NON_DEBUG_ONLY
                                : SET_PARAM_CONSTRAINT_NONE;
  // Load tesseract variables from config files. This is done after loading
  // language-specific variables from [lang].traineddata file, so that custom
  // config files can override values in [lang].traineddata file.
  for (int i = 0; i < configs_size; ++i) {
    read_config_file(configs[i], set_params_constraint);
  }
 
  // Set params specified in vars_vec (done after setting params from config
  // files, so that params in vars_vec can override those from files).
  if (vars_vec != nullptr && vars_values != nullptr) {
    for (int i = 0; i < vars_vec->size(); ++i) {
      if (!ParamUtils::SetParam((*vars_vec)[i].c_str(),
                                (*vars_values)[i].c_str(),
                                set_params_constraint, this->params())) {
        tprintf("Warning: The parameter '%s' was not found.\n", (*vars_vec)[i].c_str());
      }
    }
  }
 
  if (!tessedit_write_params_to_file.empty()) {
    FILE* params_file = fopen(tessedit_write_params_to_file.c_str(), "wb");
    if (params_file != nullptr) {
      ParamUtils::PrintParams(params_file, this->params());
      fclose(params_file);
    } else {
      tprintf("Failed to open %s for writing params.\n",
              tessedit_write_params_to_file.c_str());
    }
  }
 
  // Determine which ocr engine(s) should be loaded and used for recognition.
  if (oem != OEM_DEFAULT) tessedit_ocr_engine_mode.set_value(oem);
 
  // If we are only loading the config file (and so not planning on doing any
  // recognition) then there's nothing else do here.
  if (tessedit_init_config_only) {
    return true;
  }
 
// The various OcrEngineMode settings (see tesseract/publictypes.h) determine which
// engine-specific data files need to be loaded.
// If LSTM_ONLY is requested, the base Tesseract files are *Not* required.
#ifndef ANDROID_BUILD
#  ifdef DISABLED_LEGACY_ENGINE
  if (tessedit_ocr_engine_mode == OEM_LSTM_ONLY) {
#  else
  if (tessedit_ocr_engine_mode == OEM_LSTM_ONLY ||
      tessedit_ocr_engine_mode == OEM_TESSERACT_LSTM_COMBINED) {
#  endif  // ndef DISABLED_LEGACY_ENGINE
    if (mgr->IsComponentAvailable(TESSDATA_LSTM)) {
      lstm_recognizer_ = new LSTMRecognizer(language_data_path_prefix);
      ASSERT_HOST(lstm_recognizer_->Load(
          this->params(), lstm_use_matrix ? language : nullptr, mgr));
    } else {
      tprintf("Error: LSTM requested, but not present!! Loading tesseract.\n");
      tessedit_ocr_engine_mode.set_value(OEM_TESSERACT_ONLY);
    }
  }
#endif  // ndef ANDROID_BUILD
 
  // Load the unicharset
  if (tessedit_ocr_engine_mode == OEM_LSTM_ONLY) {
    // Avoid requiring a unicharset when we aren't running base tesseract.
#ifndef ANDROID_BUILD
    unicharset.CopyFrom(lstm_recognizer_->GetUnicharset());
#endif  // ndef ANDROID_BUILD
  }
#ifndef DISABLED_LEGACY_ENGINE
  else if (!mgr->GetComponent(TESSDATA_UNICHARSET, &fp) ||
           !unicharset.load_from_file(&fp, false)) {
    tprintf("Error: Tesseract (legacy) engine requested, but components are "
            "not present in %s!!\n", tessdata_path.c_str());
    return false;
  }
#endif  // ndef DISABLED_LEGACY_ENGINE
  if (unicharset.size() > MAX_NUM_CLASSES) {
    tprintf("Error: Size of unicharset is greater than MAX_NUM_CLASSES\n");
    return false;
  }
  right_to_left_ = unicharset.major_right_to_left();
 
#ifndef DISABLED_LEGACY_ENGINE
 
  // Setup initial unichar ambigs table and read universal ambigs.
  UNICHARSET encoder_unicharset;
  encoder_unicharset.CopyFrom(unicharset);
  unichar_ambigs.InitUnicharAmbigs(unicharset, use_ambigs_for_adaption);
  unichar_ambigs.LoadUniversal(encoder_unicharset, &unicharset);
 
  if (!tessedit_ambigs_training && mgr->GetComponent(TESSDATA_AMBIGS, &fp)) {
    unichar_ambigs.LoadUnicharAmbigs(encoder_unicharset, &fp,
                                     ambigs_debug_level,
                                     use_ambigs_for_adaption, &unicharset);
  }
 
  // Init ParamsModel.
  // Load pass1 and pass2 weights (for now these two sets are the same, but in
  // the future separate sets of weights can be generated).
  for (int p = ParamsModel::PTRAIN_PASS1; p < ParamsModel::PTRAIN_NUM_PASSES;
       ++p) {
    language_model_->getParamsModel().SetPass(
        static_cast<ParamsModel::PassEnum>(p));
    if (mgr->GetComponent(TESSDATA_PARAMS_MODEL, &fp)) {
      if (!language_model_->getParamsModel().LoadFromFp(lang.c_str(), &fp)) {
        return false;
      }
    }
  }
#endif  // ndef DISABLED_LEGACY_ENGINE
 
  return true;
}
 
// Helper returns true if the given string is in the vector of strings.
static bool IsStrInList(const STRING& str,
                        const GenericVector<STRING>& str_list) {
  for (int i = 0; i < str_list.size(); ++i) {
    if (str_list[i] == str) return true;
  }
  return false;
}
 
// Parse a string of the form [~]<lang>[+[~]<lang>]*.
// Langs with no prefix get appended to to_load, provided they
// are not in there already.
// Langs with ~ prefix get appended to not_to_load, provided they are not in
// there already.
void Tesseract::ParseLanguageString(const char* lang_str,
                                    GenericVector<STRING>* to_load,
                                    GenericVector<STRING>* not_to_load) {
  STRING remains(lang_str);
  while (remains.length() > 0) {
    // Find the start of the lang code and which vector to add to.
    const char* start = remains.c_str();
    while (*start == '+') ++start;
    GenericVector<STRING>* target = to_load;
    if (*start == '~') {
      target = not_to_load;
      ++start;
    }
    // Find the index of the end of the lang code in string start.
    int end = strlen(start);
    const char* plus = strchr(start, '+');
    if (plus != nullptr && plus - start < end) end = plus - start;
    STRING lang_code(start);
    lang_code.truncate_at(end);
    STRING next(start + end);
    remains = next;
    // Check whether lang_code is already in the target vector and add.
    if (!IsStrInList(lang_code, *target)) {
      target->push_back(lang_code);
    }
  }
}
 
// Initialize for potentially a set of languages defined by the language
// string and recursively any additional languages required by any language
// traineddata file (via tessedit_load_sublangs in its config) that is loaded.
// See init_tesseract_internal for args.
int Tesseract::init_tesseract(const char* arg0, const char* textbase,
                              const char* language, OcrEngineMode oem,
                              char** configs, int configs_size,
                              const GenericVector<STRING>* vars_vec,
                              const GenericVector<STRING>* vars_values,
                              bool set_only_non_debug_params,
                              TessdataManager* mgr) {
  GenericVector<STRING> langs_to_load;
  GenericVector<STRING> langs_not_to_load;
  ParseLanguageString(language, &langs_to_load, &langs_not_to_load);
 
  sub_langs_.delete_data_pointers();
  sub_langs_.clear();
  // Find the first loadable lang and load into this.
  // Add any languages that this language requires
  bool loaded_primary = false;
  // Load the rest into sub_langs_.
  for (int lang_index = 0; lang_index < langs_to_load.size(); ++lang_index) {
    if (!IsStrInList(langs_to_load[lang_index], langs_not_to_load)) {
      const char* lang_str = langs_to_load[lang_index].c_str();
      Tesseract* tess_to_init;
      if (!loaded_primary) {
        tess_to_init = this;
      } else {
        tess_to_init = new Tesseract;
      }
 
      int result = tess_to_init->init_tesseract_internal(
          arg0, textbase, lang_str, oem, configs, configs_size, vars_vec,
          vars_values, set_only_non_debug_params, mgr);
      // Forget that language, but keep any reader we were given.
      mgr->Clear();
 
      if (!loaded_primary) {
        if (result < 0) {
          tprintf("Failed loading language '%s'\n", lang_str);
        } else {
          ParseLanguageString(tess_to_init->tessedit_load_sublangs.c_str(),
                              &langs_to_load, &langs_not_to_load);
          loaded_primary = true;
        }
      } else {
        if (result < 0) {
          tprintf("Failed loading language '%s'\n", lang_str);
          delete tess_to_init;
        } else {
          sub_langs_.push_back(tess_to_init);
          // Add any languages that this language requires
          ParseLanguageString(tess_to_init->tessedit_load_sublangs.c_str(),
                              &langs_to_load, &langs_not_to_load);
        }
      }
    }
  }
  if (!loaded_primary) {
    tprintf("Tesseract couldn't load any languages!\n");
    return -1;  // Couldn't load any language!
  }
#ifndef DISABLED_LEGACY_ENGINE
  if (!sub_langs_.empty()) {
    // In multilingual mode word ratings have to be directly comparable,
    // so use the same language model weights for all languages:
    // use the primary language's params model if
    // tessedit_use_primary_params_model is set,
    // otherwise use default language model weights.
    if (tessedit_use_primary_params_model) {
      for (int s = 0; s < sub_langs_.size(); ++s) {
        sub_langs_[s]->language_model_->getParamsModel().Copy(
            this->language_model_->getParamsModel());
      }
      tprintf("Using params model of the primary language\n");
    } else {
      this->language_model_->getParamsModel().Clear();
      for (int s = 0; s < sub_langs_.size(); ++s) {
        sub_langs_[s]->language_model_->getParamsModel().Clear();
      }
    }
  }
 
  SetupUniversalFontIds();
#endif  // ndef DISABLED_LEGACY_ENGINE
  return 0;
}
 
// Common initialization for a single language.
// arg0 is the datapath for the tessdata directory, which could be the
// path of the tessdata directory with no trailing /, or (if tessdata
// lives in the same directory as the executable, the path of the executable,
// hence the name arg0.
// textbase is an optional output file basename (used only for training)
// language is the language code to load.
// oem controls which engine(s) will operate on the image
// configs (argv) is an array of config filenames to load variables from.
// May be nullptr.
// configs_size (argc) is the number of elements in configs.
// vars_vec is an optional vector of variables to set.
// vars_values is an optional corresponding vector of values for the variables
// in vars_vec.
// If set_only_init_params is true, then only the initialization variables
// will be set.
int Tesseract::init_tesseract_internal(const char* arg0, const char* textbase,
                                       const char* language, OcrEngineMode oem,
                                       char** configs, int configs_size,
                                       const GenericVector<STRING>* vars_vec,
                                       const GenericVector<STRING>* vars_values,
                                       bool set_only_non_debug_params,
                                       TessdataManager* mgr) {
  if (!init_tesseract_lang_data(arg0, textbase, language, oem, configs,
                                configs_size, vars_vec, vars_values,
                                set_only_non_debug_params, mgr)) {
    return -1;
  }
  if (tessedit_init_config_only) {
    return 0;
  }
  // If only LSTM will be used, skip loading Tesseract classifier's
  // pre-trained templates and dictionary.
  bool init_tesseract = tessedit_ocr_engine_mode != OEM_LSTM_ONLY;
  program_editup(textbase, init_tesseract ? mgr : nullptr,
                 init_tesseract ? mgr : nullptr);
  return 0;  // Normal exit
}
 
#ifndef DISABLED_LEGACY_ENGINE
 
// Helper builds the all_fonts table by adding new fonts from new_fonts.
static void CollectFonts(const UnicityTable<FontInfo>& new_fonts,
                         UnicityTable<FontInfo>* all_fonts) {
  for (int i = 0; i < new_fonts.size(); ++i) {
    // UnicityTable uniques as we go.
    all_fonts->push_back(new_fonts.get(i));
  }
}
 
// Helper assigns an id to lang_fonts using the index in all_fonts table.
static void AssignIds(const UnicityTable<FontInfo>& all_fonts,
                      UnicityTable<FontInfo>* lang_fonts) {
  for (int i = 0; i < lang_fonts->size(); ++i) {
    int index = all_fonts.get_id(lang_fonts->get(i));
    lang_fonts->get_mutable(i)->universal_id = index;
  }
}
 
// Set the universal_id member of each font to be unique among all
// instances of the same font loaded.
void Tesseract::SetupUniversalFontIds() {
  // Note that we can get away with bitwise copying FontInfo in
  // all_fonts, as it is a temporary structure and we avoid setting the
  // delete callback.
  using namespace std::placeholders; // for _1, _2
  UnicityTable<FontInfo> all_fonts;
  all_fonts.set_compare_callback(std::bind(CompareFontInfo, _1, _2));
 
  // Create the universal ID table.
  CollectFonts(get_fontinfo_table(), &all_fonts);
  for (int i = 0; i < sub_langs_.size(); ++i) {
    CollectFonts(sub_langs_[i]->get_fontinfo_table(), &all_fonts);
  }
  // Assign ids from the table to each font table.
  AssignIds(all_fonts, &get_fontinfo_table());
  for (int i = 0; i < sub_langs_.size(); ++i) {
    AssignIds(all_fonts, &sub_langs_[i]->get_fontinfo_table());
  }
  font_table_size_ = all_fonts.size();
}
 
// init the LM component
int Tesseract::init_tesseract_lm(const char* arg0, const char* textbase,
                                 const char* language, TessdataManager* mgr) {
  if (!init_tesseract_lang_data(arg0, textbase, language, OEM_TESSERACT_ONLY,
                                nullptr, 0, nullptr, nullptr, false, mgr))
    return -1;
  getDict().SetupForLoad(Dict::GlobalDawgCache());
  getDict().Load(lang, mgr);
  getDict().FinishLoad();
  return 0;
}
 
#endif  // ndef DISABLED_LEGACY_ENGINE
 
void Tesseract::end_tesseract() { end_recog(); }
 
/* Define command type identifiers */
 
enum CMD_EVENTS {
  ACTION_1_CMD_EVENT,
  RECOG_WERDS,
  RECOG_PSEUDO,
  ACTION_2_CMD_EVENT
};
}  // namespace tesseract