boxchar.h

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/**********************************************************************
 * File:        boxchar.h
 * Description: Simple class to associate a Tesseract classification unit with
 *              its bounding box so that the boxes can be rotated as the image
 *              is rotated for degradation.  Also includes routines to output
 *              the character-tagged boxes to a boxfile.
 * Author:      Ray Smith
 *
 * (C) Copyright 2013, 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.
 *
 **********************************************************************/
 
#ifndef TESSERACT_TRAINING_BOXCHAR_H_
#define TESSERACT_TRAINING_BOXCHAR_H_
 
#include <string>
#include <vector>
 
#include <allheaders.h>   // for Leptonica API
#if (LIBLEPT_MAJOR_VERSION == 1 && LIBLEPT_MINOR_VERSION >= 83) || LIBLEPT_MAJOR_VERSION > 1
#include <pix_internal.h> // for fast access to Box geometry
#endif
#include <tesseract/export.h>
 
namespace tesseract {
 
class BoxChar {
public:
  BoxChar(const char *utf8_str, int len);
 
  ~BoxChar();
 
  // Accessors.
  const std::string &ch() const {
    return ch_;
  }
  const Box *box() const {
    return box_;
  }
  const int &page() const {
    return page_;
  }
  void set_rtl_index(int index) {
    rtl_index_ = index;
  }
  const int &rtl_index() const {
    return rtl_index_;
  }
 
  // Set the box_ member.
  void AddBox(int x, int y, int width, int height);
 
  void set_page(int page) {
    page_ = page;
  }
 
  std::string *mutable_ch() {
    return &ch_;
  }
  Box *mutable_box() {
    return box_;
  }
 
  // Sort function for sorting by left edge of box. Note that this will not
  // work properly until after InsertNewlines and InsertSpaces.
  bool operator<(const BoxChar &other) const {
    if (box_ == nullptr) {
      return true;
    }
    if (other.box_ == nullptr) {
      return false;
    }
    return box_->x < other.box_->x;
  }
  // Increments *num_rtl and *num_ltr according to the directionality of
  // characters in the box.
  void GetDirection(int *num_rtl, int *num_ltr) const;
  // Reverses the order of unicodes within the box. If Pango generates a
  // ligature, these will get reversed on output, so reverse now.
  void ReverseUnicodesInBox();
 
  static void TranslateBoxes(int xshift, int yshift, std::vector<BoxChar *> *boxes);
 
  // Prepares for writing the boxes to a file by inserting newlines, spaces,
  // and re-ordering so the boxes are strictly left-to-right.
  static void PrepareToWrite(std::vector<BoxChar *> *boxes);
  // Inserts newline (tab) characters into the vector at newline positions.
  static void InsertNewlines(bool rtl_rules, bool vertical_rules, std::vector<BoxChar *> *boxes);
  // Converts nullptr boxes to space characters, with appropriate bounding
  // boxes.
  static void InsertSpaces(bool rtl_rules, bool vertical_rules, std::vector<BoxChar *> *boxes);
  // Reorders text in a right-to-left script in left-to-right order.
  static void ReorderRTLText(std::vector<BoxChar *> *boxes);
  // Returns true if the vector contains mostly RTL characters.
  static bool ContainsMostlyRTL(const std::vector<BoxChar *> &boxes);
  // Returns true if the text is mostly laid out vertically.
  static bool MostlyVertical(const std::vector<BoxChar *> &boxes);
 
  // Returns the total length of all the strings in the boxes.
  static int TotalByteLength(const std::vector<BoxChar *> &boxes);
 
  // Rotate the vector of boxes between start and end by the given rotation.
  // The rotation is in radians clockwise about the given center.
  static void RotateBoxes(float rotation, int xcenter, int ycenter, int start_box, int end_box,
                          std::vector<BoxChar *> *boxes);
 
  // Create a tesseract box file from the vector of boxes. The image height
  // is needed to convert to tesseract coordinates.
  static void WriteTesseractBoxFile(const std::string &name, int height,
                                    const std::vector<BoxChar *> &boxes);
  // Gets the tesseract box file as a string from the vector of boxes.
  // The image height is needed to convert to tesseract coordinates.
  static std::string GetTesseractBoxStr(int height, const std::vector<BoxChar *> &boxes);
 
private:
  std::string ch_;
  Box *box_;
  int page_;
  // If the box is an RTL character, contains the original position in the
  // array of boxes (before reversal), otherwise -1.
  int rtl_index_;
};
 
// Sort predicate to sort a vector of BoxChar*.
struct BoxCharPtrSort {
  bool operator()(const BoxChar *box1, const BoxChar *box2) const {
    if (box1->rtl_index() >= 0 && box2->rtl_index() >= 0) {
      return box2->rtl_index() < box1->rtl_index();
    }
    return *box1 < *box2;
  }
};
 
} // namespace tesseract
 
#endif // TESSERACT_TRAINING_BOXCHAR_H_