/******************************************************************************

 *

 * File:        chop.cpp  (Formerly chop.c)

 * Author:      Mark Seaman, OCR Technology

 *

 * (c) Copyright 1987, Hewlett-Packard Company.

 ** 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.

 *

 *****************************************************************************/

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

              I n c l u d e s

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

#define _USE_MATH_DEFINES // for M_PI

#include "chop.h"

#include <cmath> // for M_PI

#include "outlines.h"

#include "plotedges.h"

#include "wordrec.h"

// Include automatically generated configuration file if running autoconf.

#ifdef HAVE_CONFIG_H

#  include "config_auto.h"

#endif

namespace tesseract {

// Show if the line is going in the positive or negative X direction.

static int direction(const EDGEPT *point) {

  //* direction to return

  int dir = 0;

  //* prev point

  const EDGEPT *prev = point->prev;

  //* next point

  const EDGEPT *next = point->next;

  if (((prev->pos.x <= point->pos.x) && (point->pos.x < next->pos.x)) ||

      ((prev->pos.x < point->pos.x) && (point->pos.x <= next->pos.x))) {

    dir = 1;

  }

  if (((prev->pos.x >= point->pos.x) && (point->pos.x > next->pos.x)) ||

      ((prev->pos.x > point->pos.x) && (point->pos.x >= next->pos.x))) {

    dir = -1;

  }

  return dir;

}

/**

 * @name point_priority

 *

 * Assign a priority to and edge point that might be used as part of a

 * split. The argument should be of type EDGEPT.

 */

PRIORITY Wordrec::point_priority(EDGEPT *point) {

  return static_cast<PRIORITY>(angle_change(point->prev, point, point->next));

}

/**

 * @name add_point_to_list

 *

 * Add an edge point to a POINT_GROUP containing a list of other points.

 */

void Wordrec::add_point_to_list(PointHeap *point_heap, EDGEPT *point) {

  if (point_heap->size() < MAX_NUM_POINTS - 2) {

    PointPair pair(point_priority(point), point);

    point_heap->Push(&pair);

  }

#ifndef GRAPHICS_DISABLED

  if (chop_debug > 2) {

    mark_outline(point);

  }

#endif

}

// Returns true if the edgept supplied as input is an inside angle.  This

// is determined by the angular change of the vectors from point to point.

bool Wordrec::is_inside_angle(EDGEPT *pt) {

  return angle_change(pt->prev, pt, pt->next) < chop_inside_angle;

}

/**

 * @name angle_change

 *

 * Return the change in angle (degrees) of the line segments between

 * points one and two, and two and three.

 */

int Wordrec::angle_change(EDGEPT *point1, EDGEPT *point2, EDGEPT *point3) {

  VECTOR vector1;

  VECTOR vector2;

  int angle;

  /* Compute angle */

  vector1.x = point2->pos.x - point1->pos.x;

  vector1.y = point2->pos.y - point1->pos.y;

  vector2.x = point3->pos.x - point2->pos.x;

  vector2.y = point3->pos.y - point2->pos.y;

  /* Use cross product */

  float length = std::sqrt(static_cast<float>(vector1.length2()) * vector2.length2());

  if (static_cast<int>(length) == 0) {

    return (0);

  }

  auto f = vector1.cross(vector2) / length;

  // Avoid FP exception in std::asin caused by illegal values of f

  // (caused by rounding errors).

  if (f <= -1.0f) {

    angle = -90;

  } else if (f >= 1.0f) {

    angle = 90;

  } else {

    angle = static_cast<int>(floor(std::asin(f) / M_PI * 180.0 + 0.5));

    // Use dot product.

    if (vector1.dot(vector2) < 0) {

      angle = 180 - angle;

    }

    // Adjust angle.

    if (angle > 180) {

      angle -= 360;

    } else if (angle <= -180) {

      angle += 360;

    }

  }

  return angle;

}

/**

 * @name pick_close_point

 *

 * Choose the edge point that is closest to the critical point.  This

 * point may not be exactly vertical from the critical point.

 */

EDGEPT *Wordrec::pick_close_point(EDGEPT *critical_point, EDGEPT *vertical_point, int *best_dist) {

  EDGEPT *best_point = nullptr;

  int this_distance;

  bool found_better;

  do {

    found_better = false;

    this_distance = edgept_dist(critical_point, vertical_point);

    if (this_distance <= *best_dist) {

      if (!(same_point(critical_point->pos, vertical_point->pos) ||

            same_point(critical_point->pos, vertical_point->next->pos) ||

            (best_point && same_point(best_point->pos, vertical_point->pos)) ||

            is_exterior_point(critical_point, vertical_point))) {

        *best_dist = this_distance;

        best_point = vertical_point;

        if (chop_vertical_creep) {

          found_better = true;

        }

      }

    }

    vertical_point = vertical_point->next;

  } while (found_better == true);

  return (best_point);

}

/**

 * @name prioritize_points

 *

 * Find a list of edge points from the outer outline of this blob.  For

 * each of these points assign a priority.  Sort these points using a

 * heap structure so that they can be visited in order.

 */

void Wordrec::prioritize_points(TESSLINE *outline, PointHeap *points) {

  EDGEPT *this_point;

  EDGEPT *local_min = nullptr;

  EDGEPT *local_max = nullptr;

  this_point = outline->loop;

  local_min = this_point;

  local_max = this_point;

  do {

    if (this_point->vec.y < 0) {

      /* Look for minima */

      if (local_max != nullptr) {

        new_max_point(local_max, points);

      } else if (is_inside_angle(this_point)) {

        add_point_to_list(points, this_point);

      }

      local_max = nullptr;

      local_min = this_point->next;

    } else if (this_point->vec.y > 0) {

      /* Look for maxima */

      if (local_min != nullptr) {

        new_min_point(local_min, points);

      } else if (is_inside_angle(this_point)) {

        add_point_to_list(points, this_point);

      }

      local_min = nullptr;

      local_max = this_point->next;

    } else {

      /* Flat area */

      if (local_max != nullptr) {

        if (local_max->prev->vec.y != 0) {

          new_max_point(local_max, points);

        }

        local_max = this_point->next;

        local_min = nullptr;

      } else {

        if (local_min->prev->vec.y != 0) {

          new_min_point(local_min, points);

        }

        local_min = this_point->next;

        local_max = nullptr;

      }

    }

    /* Next point */

    this_point = this_point->next;

  } while (this_point != outline->loop);

}

/**

 * @name new_min_point

 *

 * Found a new minimum point try to decide whether to save it or not.

 * Return the new value for the local minimum.  If a point is saved then

 * the local minimum is reset to nullptr.

 */

void Wordrec::new_min_point(EDGEPT *local_min, PointHeap *points) {

  int16_t dir;

  dir = direction(local_min);

  if (dir < 0) {

    add_point_to_list(points, local_min);

    return;

  }

  if (dir == 0 && point_priority(local_min) < 0) {

    add_point_to_list(points, local_min);

    return;

  }

}

/**

 * @name new_max_point

 *

 * Found a new minimum point try to decide whether to save it or not.

 * Return the new value for the local minimum.  If a point is saved then

 * the local minimum is reset to nullptr.

 */

void Wordrec::new_max_point(EDGEPT *local_max, PointHeap *points) {

  int16_t dir;

  dir = direction(local_max);

  if (dir > 0) {

    add_point_to_list(points, local_max);

    return;

  }

  if (dir == 0 && point_priority(local_max) < 0) {

    add_point_to_list(points, local_max);

    return;

  }

}

/**

 * @name vertical_projection_point

 *

 * For one point on the outline, find the corresponding point on the

 * other side of the outline that is a likely projection for a split

 * point.  This is done by iterating through the edge points until the

 * X value of the point being looked at is greater than the X value of

 * the split point.  Ensure that the point being returned is not right

 * next to the split point.  Return the edge point in *best_point as

 * a result, and any points that were newly created are also saved on

 * the new_points list.

 */

void Wordrec::vertical_projection_point(EDGEPT *split_point, EDGEPT *target_point,

                                        EDGEPT **best_point, EDGEPT_CLIST *new_points) {

  EDGEPT *p;           /* Iterator */

  EDGEPT *this_edgept; /* Iterator */

  EDGEPT_C_IT new_point_it(new_points);

  int x = split_point->pos.x;     /* X value of vertical */

  int best_dist = LARGE_DISTANCE; /* Best point found */

  if (*best_point != nullptr) {

    best_dist = edgept_dist(split_point, *best_point);

  }

  p = target_point;

  /* Look at each edge point */

  do {

    if (((p->pos.x <= x && x <= p->next->pos.x) || (p->next->pos.x <= x && x <= p->pos.x)) &&

        !same_point(split_point->pos, p->pos) && !same_point(split_point->pos, p->next->pos) &&

        !p->IsChopPt() && (*best_point == nullptr || !same_point((*best_point)->pos, p->pos))) {

      if (near_point(split_point, p, p->next, &this_edgept)) {

        new_point_it.add_before_then_move(this_edgept);

      }

      if (*best_point == nullptr) {

        best_dist = edgept_dist(split_point, this_edgept);

      }

      this_edgept = pick_close_point(split_point, this_edgept, &best_dist);

      if (this_edgept) {

        *best_point = this_edgept;

      }

    }

    p = p->next;

  } while (p != target_point);

}

} // namespace tesseract