renderer.cpp

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// File:        renderer.cpp
// Description: Rendering interface to inject into TessBaseAPI
//
// (C) Copyright 2011, Google Inc.
// 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.
//
 
#ifdef HAVE_CONFIG_H
#  include "config_auto.h"
#endif
#include <tesseract/baseapi.h>
#include <tesseract/renderer.h>
#include <cstring>
#include <memory>     // std::unique_ptr
#include <string>     // std::string
#include "serialis.h" // Serialize
 
namespace tesseract {
 
/**********************************************************************
 * Base Renderer interface implementation
 **********************************************************************/
TessResultRenderer::TessResultRenderer(const char *outputbase, const char *extension)
    : next_(nullptr)
    , fout_(stdout)
    , file_extension_(extension)
    , title_("")
    , imagenum_(-1)
    , happy_(true) {
  if (strcmp(outputbase, "-") && strcmp(outputbase, "stdout")) {
    std::string outfile = std::string(outputbase) + "." + extension;
    fout_ = fopen(outfile.c_str(), "wb");
    if (fout_ == nullptr) {
      happy_ = false;
    }
  }
}
 
TessResultRenderer::~TessResultRenderer() {
  if (fout_ != nullptr) {
    if (fout_ != stdout) {
      fclose(fout_);
    } else {
      clearerr(fout_);
    }
  }
  delete next_;
}
 
void TessResultRenderer::insert(TessResultRenderer *next) {
  if (next == nullptr) {
    return;
  }
 
  TessResultRenderer *remainder = next_;
  next_ = next;
  if (remainder) {
    while (next->next_ != nullptr) {
      next = next->next_;
    }
    next->next_ = remainder;
  }
}
 
bool TessResultRenderer::BeginDocument(const char *title) {
  if (!happy_) {
    return false;
  }
  title_ = title;
  imagenum_ = -1;
  bool ok = BeginDocumentHandler();
  if (next_) {
    ok = next_->BeginDocument(title) && ok;
  }
  return ok;
}
 
bool TessResultRenderer::AddImage(TessBaseAPI *api) {
  if (!happy_) {
    return false;
  }
  ++imagenum_;
  bool ok = AddImageHandler(api);
  if (next_) {
    ok = next_->AddImage(api) && ok;
  }
  return ok;
}
 
bool TessResultRenderer::EndDocument() {
  if (!happy_) {
    return false;
  }
  bool ok = EndDocumentHandler();
  if (next_) {
    ok = next_->EndDocument() && ok;
  }
  return ok;
}
 
void TessResultRenderer::AppendString(const char *s) {
  if (s == nullptr) {
    return;
  }
  AppendData(s, strlen(s));
}
 
void TessResultRenderer::AppendData(const char *s, int len) {
  if (!tesseract::Serialize(fout_, s, len)) {
    happy_ = false;
  }
  fflush(fout_);
}
 
bool TessResultRenderer::BeginDocumentHandler() {
  return happy_;
}
 
bool TessResultRenderer::EndDocumentHandler() {
  return happy_;
}
 
/**********************************************************************
 * UTF8 Text Renderer interface implementation
 **********************************************************************/
TessTextRenderer::TessTextRenderer(const char *outputbase)
    : TessResultRenderer(outputbase, "txt") {}
 
bool TessTextRenderer::AddImageHandler(TessBaseAPI *api) {
  const std::unique_ptr<const char[]> utf8(api->GetUTF8Text());
  if (utf8 == nullptr) {
    return false;
  }
 
  const char *pageSeparator = api->GetStringVariable("page_separator");
  if (pageSeparator != nullptr && *pageSeparator != '\0' && imagenum() > 0) {
    AppendString(pageSeparator);
  }
 
  AppendString(utf8.get());
 
  return true;
}
 
/**********************************************************************
 * TSV Text Renderer interface implementation
 **********************************************************************/
TessTsvRenderer::TessTsvRenderer(const char *outputbase) : TessResultRenderer(outputbase, "tsv") {
  font_info_ = false;
}
 
TessTsvRenderer::TessTsvRenderer(const char *outputbase, bool font_info)
    : TessResultRenderer(outputbase, "tsv") {
  font_info_ = font_info;
}
 
bool TessTsvRenderer::BeginDocumentHandler() {
  // Output TSV column headings
  AppendString(
      "level\tpage_num\tblock_num\tpar_num\tline_num\tword_"
      "num\tleft\ttop\twidth\theight\tconf\ttext\n");
  return true;
}
 
bool TessTsvRenderer::EndDocumentHandler() {
  return true;
}
 
bool TessTsvRenderer::AddImageHandler(TessBaseAPI *api) {
  const std::unique_ptr<const char[]> tsv(api->GetTSVText(imagenum()));
  if (tsv == nullptr) {
    return false;
  }
 
  AppendString(tsv.get());
 
  return true;
}
 
/**********************************************************************
 * UNLV Text Renderer interface implementation
 **********************************************************************/
TessUnlvRenderer::TessUnlvRenderer(const char *outputbase)
    : TessResultRenderer(outputbase, "unlv") {}
 
bool TessUnlvRenderer::AddImageHandler(TessBaseAPI *api) {
  const std::unique_ptr<const char[]> unlv(api->GetUNLVText());
  if (unlv == nullptr) {
    return false;
  }
 
  AppendString(unlv.get());
 
  return true;
}
 
/**********************************************************************
 * BoxText Renderer interface implementation
 **********************************************************************/
TessBoxTextRenderer::TessBoxTextRenderer(const char *outputbase)
    : TessResultRenderer(outputbase, "box") {}
 
bool TessBoxTextRenderer::AddImageHandler(TessBaseAPI *api) {
  const std::unique_ptr<const char[]> text(api->GetBoxText(imagenum()));
  if (text == nullptr) {
    return false;
  }
 
  AppendString(text.get());
 
  return true;
}
 
#ifndef DISABLED_LEGACY_ENGINE
 
/**********************************************************************
 * Osd Text Renderer interface implementation
 **********************************************************************/
TessOsdRenderer::TessOsdRenderer(const char *outputbase) : TessResultRenderer(outputbase, "osd") {}
 
bool TessOsdRenderer::AddImageHandler(TessBaseAPI *api) {
  const std::unique_ptr<const char[]> osd(api->GetOsdText(imagenum()));
  if (osd == nullptr) {
    return false;
  }
 
  AppendString(osd.get());
 
  return true;
}
 
#endif // ndef DISABLED_LEGACY_ENGINE
 
} // namespace tesseract