polyblk.cpp

/**********************************************************************
 * File:        polyblk.cpp  (Formerly poly_block.c)
 * Description: Polygonal blocks
 *
 * (C) Copyright 1993, 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 "polyblk.h"

#include "elst.h"

#include <cctype>
#include <cinttypes> // PRId32
#include <cmath>
#include <cstdio>
#include <memory> // std::unique_ptr

namespace tesseract {

#define INTERSECTING INT16_MAX

POLY_BLOCK::POLY_BLOCK(ICOORDELT_LIST *points, PolyBlockType t) {
  ICOORDELT_IT v = &vertices;

  vertices.clear();
  v.move_to_first();
  v.add_list_before(points);
  compute_bb();
  type = t;
}

// Initialize from box coordinates.
POLY_BLOCK::POLY_BLOCK(const TBOX &tbox, PolyBlockType t) {
  vertices.clear();
  ICOORDELT_IT v = &vertices;
  v.move_to_first();
  v.add_to_end(new ICOORDELT(tbox.left(), tbox.top()));
  v.add_to_end(new ICOORDELT(tbox.left(), tbox.bottom()));
  v.add_to_end(new ICOORDELT(tbox.right(), tbox.bottom()));
  v.add_to_end(new ICOORDELT(tbox.right(), tbox.top()));
  compute_bb();
  type = t;
}

/**
 * @name POLY_BLOCK::compute_bb
 *
 * Compute the bounding box from the outline points.
 */

void POLY_BLOCK::compute_bb() { // constructor
  ICOORD ibl, itr;              // integer bb
  ICOORD botleft;               // bounding box
  ICOORD topright;
  ICOORD pos;                   // current pos;
  ICOORDELT_IT pts = &vertices; // iterator

  botleft = *pts.data();
  topright = botleft;
  do {
    pos = *pts.data();
    if (pos.x() < botleft.x()) {
      // get bounding box
      botleft = ICOORD(pos.x(), botleft.y());
    }
    if (pos.y() < botleft.y()) {
      botleft = ICOORD(botleft.x(), pos.y());
    }
    if (pos.x() > topright.x()) {
      topright = ICOORD(pos.x(), topright.y());
    }
    if (pos.y() > topright.y()) {
      topright = ICOORD(topright.x(), pos.y());
    }
    pts.forward();
  } while (!pts.at_first());
  ibl = ICOORD(botleft.x(), botleft.y());
  itr = ICOORD(topright.x(), topright.y());
  box = TBOX(ibl, itr);
}

/**
 * @name POLY_BLOCK::winding_number
 *
 * Return the winding number of the outline around the given point.
 * @param point point to wind around
 */

int16_t POLY_BLOCK::winding_number(const ICOORD &point) {
  int16_t count;               // winding count
  ICOORD pt;                   // current point
  ICOORD vec;                  // point to current point
  ICOORD vvec;                 // current point to next point
  int32_t cross;               // cross product
  ICOORDELT_IT it = &vertices; // iterator

  count = 0;
  do {
    pt = *it.data();
    vec = pt - point;
    vvec = *it.data_relative(1) - pt;
    // crossing the line
    if (vec.y() <= 0 && vec.y() + vvec.y() > 0) {
      cross = vec * vvec; // cross product
      if (cross > 0) {
        count++; // crossing right half
      } else if (cross == 0) {
        return INTERSECTING; // going through point
      }
    } else if (vec.y() > 0 && vec.y() + vvec.y() <= 0) {
      cross = vec * vvec;
      if (cross < 0) {
        count--; // crossing back
      } else if (cross == 0) {
        return INTERSECTING; // illegal
      }
    } else if (vec.y() == 0 && vec.x() == 0) {
      return INTERSECTING;
    }
    it.forward();
  } while (!it.at_first());
  return count; // winding number
}

/// @return true if other is inside this.
bool POLY_BLOCK::contains(POLY_BLOCK *other) {
  int16_t count;               // winding count
  ICOORDELT_IT it = &vertices; // iterator
  ICOORD vertex;

  if (!box.overlap(*(other->bounding_box()))) {
    return false; // can't be contained
  }

  /* check that no vertex of this is inside other */

  do {
    vertex = *it.data();
    // get winding number
    count = other->winding_number(vertex);
    if (count != INTERSECTING) {
      if (count != 0) {
        return false;
      }
    }
    it.forward();
  } while (!it.at_first());

  /* check that all vertices of other are inside this */

  // switch lists
  it.set_to_list(other->points());
  do {
    vertex = *it.data();
    // try other way round
    count = winding_number(vertex);
    if (count != INTERSECTING) {
      if (count == 0) {
        return false;
      }
    }
    it.forward();
  } while (!it.at_first());
  return true;
}

/**
 * @name POLY_BLOCK::rotate
 *
 * Rotate the POLY_BLOCK.
 * @param rotation cos, sin of angle
 */

void POLY_BLOCK::rotate(FCOORD rotation) {
  FCOORD pos;                   // current pos;
  ICOORDELT *pt;                // current point
  ICOORDELT_IT pts = &vertices; // iterator

  do {
    pt = pts.data();
    pos.set_x(pt->x());
    pos.set_y(pt->y());
    pos.rotate(rotation);
    pt->set_x(static_cast<TDimension>(floor(pos.x() + 0.5)));
    pt->set_y(static_cast<TDimension>(floor(pos.y() + 0.5)));
    pts.forward();
  } while (!pts.at_first());
  compute_bb();
}

/**
 * @name POLY_BLOCK::reflect_in_y_axis
 *
 * Reflect the coords of the polygon in the y-axis. (Flip the sign of x.)
 */

void POLY_BLOCK::reflect_in_y_axis() {
  ICOORDELT *pt;                // current point
  ICOORDELT_IT pts = &vertices; // Iterator.

  do {
    pt = pts.data();
    pt->set_x(-pt->x());
    pts.forward();
  } while (!pts.at_first());
  compute_bb();
}

/**
 * POLY_BLOCK::move
 *
 * Move the POLY_BLOCK.
 * @param shift x,y translation vector
 */

void POLY_BLOCK::move(ICOORD shift) {
  ICOORDELT *pt;                // current point
  ICOORDELT_IT pts = &vertices; // iterator

  do {
    pt = pts.data();
    *pt += shift;
    pts.forward();
  } while (!pts.at_first());
  compute_bb();
}

#ifndef GRAPHICS_DISABLED
void POLY_BLOCK::plot(ScrollView *window, int32_t num) {
  ICOORDELT_IT v = &vertices;

  window->Pen(ColorForPolyBlockType(type));

  v.move_to_first();

  if (num > 0) {
    window->TextAttributes("Times", 80, false, false, false);
    char temp_buff[34];
#  if !defined(_WIN32) || defined(__MINGW32__)
    snprintf(temp_buff, sizeof(temp_buff), "%" PRId32, num);
#  else
    _ltoa(num, temp_buff, 10);
#  endif
    window->Text(v.data()->x(), v.data()->y(), temp_buff);
  }

  window->SetCursor(v.data()->x(), v.data()->y());
  for (v.mark_cycle_pt(); !v.cycled_list(); v.forward()) {
    window->DrawTo(v.data()->x(), v.data()->y());
  }
  v.move_to_first();
  window->DrawTo(v.data()->x(), v.data()->y());
}

void POLY_BLOCK::fill(ScrollView *window, ScrollView::Color colour) {
  ICOORDELT_IT s_it;

  std::unique_ptr<PB_LINE_IT> lines(new PB_LINE_IT(this));
  window->Pen(colour);

  for (auto y = this->bounding_box()->bottom(); y <= this->bounding_box()->top(); y++) {
    const std::unique_ptr</*non-const*/ ICOORDELT_LIST> segments(lines->get_line(y));
    if (!segments->empty()) {
      s_it.set_to_list(segments.get());
      for (s_it.mark_cycle_pt(); !s_it.cycled_list(); s_it.forward()) {
        // Note different use of ICOORDELT, x coord is x coord of pixel
        // at the start of line segment, y coord is length of line segment
        // Last pixel is start pixel + length.
        auto width = s_it.data()->y();
        window->SetCursor(s_it.data()->x(), y);
        window->DrawTo(s_it.data()->x() + static_cast<float>(width), y);
      }
    }
  }
}
#endif

/// @return true if the polygons of other and this overlap.
bool POLY_BLOCK::overlap(POLY_BLOCK *other) {
  int16_t count;               // winding count
  ICOORDELT_IT it = &vertices; // iterator
  ICOORD vertex;

  if (!box.overlap(*(other->bounding_box()))) {
    return false; // can't be any overlap.
  }

  /* see if a vertex of this is inside other */

  do {
    vertex = *it.data();
    // get winding number
    count = other->winding_number(vertex);
    if (count != INTERSECTING) {
      if (count != 0) {
        return true;
      }
    }
    it.forward();
  } while (!it.at_first());

  /* see if a vertex of other is inside this */

  // switch lists
  it.set_to_list(other->points());
  do {
    vertex = *it.data();
    // try other way round
    count = winding_number(vertex);
    if (count != INTERSECTING) {
      if (count != 0) {
        return true;
      }
    }
    it.forward();
  } while (!it.at_first());
  return false;
}

ICOORDELT_LIST *PB_LINE_IT::get_line(TDimension y) {
  ICOORDELT_IT v, r;
  ICOORDELT_LIST *result;
  ICOORDELT *x, *current, *previous;
  float fy = y + 0.5f;
  result = new ICOORDELT_LIST();
  r.set_to_list(result);
  v.set_to_list(block->points());

  for (v.mark_cycle_pt(); !v.cycled_list(); v.forward()) {
    if (((v.data_relative(-1)->y() > y) && (v.data()->y() <= y)) ||
        ((v.data_relative(-1)->y() <= y) && (v.data()->y() > y))) {
      previous = v.data_relative(-1);
      current = v.data();
      float fx =
          0.5f + previous->x() +
          (current->x() - previous->x()) * (fy - previous->y()) / (current->y() - previous->y());
      x = new ICOORDELT(static_cast<TDimension>(fx), 0);
      r.add_to_end(x);
    }
  }

  if (!r.empty()) {
    r.sort([](const ICOORDELT *p1, const ICOORDELT *p2) {
      if (p1->x() < p2->x()) {
        return (-1);
      } else if (p1->x() > p2->x()) {
        return (1);
      } else {
        return (0);
      }
      });
    for (r.mark_cycle_pt(); !r.cycled_list(); r.forward()) {
      x = r.data();
    }
    for (r.mark_cycle_pt(); !r.cycled_list(); r.forward()) {
      r.data()->set_y(r.data_relative(1)->x() - r.data()->x());
      r.forward();
      delete (r.extract());
    }
  }

  return result;
}

#ifndef GRAPHICS_DISABLED
/// Returns a color to draw the given type.
ScrollView::Color POLY_BLOCK::ColorForPolyBlockType(PolyBlockType type) {
  // Keep kPBColors in sync with PolyBlockType.
  const ScrollView::Color kPBColors[PT_COUNT] = {
      ScrollView::WHITE,       // Type is not yet known. Keep as the 1st element.
      ScrollView::BLUE,        // Text that lives inside a column.
      ScrollView::CYAN,        // Text that spans more than one column.
      ScrollView::MEDIUM_BLUE, // Text that is in a cross-column pull-out
                               // region.
      ScrollView::AQUAMARINE,  // Partition belonging to an equation region.
      ScrollView::SKY_BLUE,    // Partition belonging to an inline equation
                               // region.
      ScrollView::MAGENTA,     // Partition belonging to a table region.
      ScrollView::GREEN,       // Text-line runs vertically.
      ScrollView::LIGHT_BLUE,  // Text that belongs to an image.
      ScrollView::RED,         // Image that lives inside a column.
      ScrollView::YELLOW,      // Image that spans more than one column.
      ScrollView::ORANGE,      // Image in a cross-column pull-out region.
      ScrollView::BROWN,       // Horizontal Line.
      ScrollView::DARK_GREEN,  // Vertical Line.
      ScrollView::GREY         // Lies outside of any column.
  };
  if (type < PT_COUNT) {
    return kPBColors[type];
  }
  return ScrollView::WHITE;
}
#endif // !GRAPHICS_DISABLED

} // namespace tesseract