seam.h

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/******************************************************************************
 *
 * File:        seam.h
 * Author:      Mark Seaman, SW Productivity
 *
 * (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.
 *
 *****************************************************************************/
#ifndef SEAM_H
#define SEAM_H
 
// Include automatically generated configuration file if running autoconf.
#ifdef HAVE_CONFIG_H
#  include "config_auto.h"
#endif
 
#include "blobs.h"
#include "split.h"
 
namespace tesseract {
 
using PRIORITY = float; /*  PRIORITY  */
 
class SEAM {
public:
  // A seam with no splits
  SEAM(float priority, const TPOINT &location)
      : priority_(priority), location_(location), num_splits_(0) {}
  // A seam with a single split point.
  SEAM(float priority, const TPOINT &location, const SPLIT &split)
      : priority_(priority), location_(location), num_splits_(1) {
    splits_[0] = split;
  }
  // Default copy constructor, operator= and destructor are OK!
 
  // Accessors.
  float priority() const {
    return priority_;
  }
  void set_priority(float priority) {
    priority_ = priority;
  }
  bool HasAnySplits() const {
    return num_splits_ > 0;
  }
 
  // Returns the bounding box of all the points in the seam.
  TBOX bounding_box() const;
 
  // Returns true if other can be combined into *this.
  bool CombineableWith(const SEAM &other, int max_x_dist, float max_total_priority) const {
    int dist = location_.x - other.location_.x;
    return -max_x_dist < dist && dist < max_x_dist &&
           num_splits_ + other.num_splits_ <= kMaxNumSplits &&
           priority_ + other.priority_ < max_total_priority && !OverlappingSplits(other) &&
           !SharesPosition(other);
  }
 
  // Combines other into *this. Only works if CombinableWith returned true.
  void CombineWith(const SEAM &other) {
    priority_ += other.priority_;
    location_ += other.location_;
    location_ /= 2;
 
    for (uint8_t s = 0; s < other.num_splits_ && num_splits_ < kMaxNumSplits; ++s) {
      splits_[num_splits_++] = other.splits_[s];
    }
  }
 
  // Returns true if the given blob contains all splits of *this SEAM.
  bool ContainedByBlob(const TBLOB &blob) const {
    for (int s = 0; s < num_splits_; ++s) {
      if (!splits_[s].ContainedByBlob(blob)) {
        return false;
      }
    }
    return true;
  }
 
  // Returns true if the given EDGEPT is used by this SEAM, checking only
  // the EDGEPT pointer, not the coordinates.
  bool UsesPoint(const EDGEPT *point) const {
    for (int s = 0; s < num_splits_; ++s) {
      if (splits_[s].UsesPoint(point)) {
        return true;
      }
    }
    return false;
  }
  // Returns true if *this and other share any common point, by coordinates.
  bool SharesPosition(const SEAM &other) const {
    for (int s = 0; s < num_splits_; ++s) {
      for (int t = 0; t < other.num_splits_; ++t) {
        if (splits_[s].SharesPosition(other.splits_[t])) {
          return true;
        }
      }
    }
    return false;
  }
  // Returns true if *this and other have any vertically overlapping splits.
  bool OverlappingSplits(const SEAM &other) const {
    for (int s = 0; s < num_splits_; ++s) {
      TBOX split1_box = splits_[s].bounding_box();
      for (int t = 0; t < other.num_splits_; ++t) {
        TBOX split2_box = other.splits_[t].bounding_box();
        if (split1_box.y_overlap(split2_box)) {
          return true;
        }
      }
    }
    return false;
  }
 
  // Marks the edgepts used by the seam so the segments made by the cut
  // never get split further by another seam in the future.
  void Finalize() {
    for (int s = 0; s < num_splits_; ++s) {
      splits_[s].point1->MarkChop();
      splits_[s].point2->MarkChop();
    }
  }
 
  // Returns true if the splits in *this SEAM appear OK in the sense that they
  // do not cross any outlines and do not chop off any ridiculously small
  // pieces.
  bool IsHealthy(const TBLOB &blob, int min_points, int min_area) const;
 
  // Computes the widthp_/widthn_ range for all existing SEAMs and for *this
  // seam, which is about to be inserted at insert_index. Returns false if
  // any of the computations fails, as this indicates an invalid chop.
  // widthn_/widthp_ are only changed if modify is true.
  bool PrepareToInsertSeam(const std::vector<SEAM *> &seams, const std::vector<TBLOB *> &blobs,
                           int insert_index, bool modify);
  // Computes the widthp_/widthn_ range. Returns false if not all the splits
  // are accounted for. widthn_/widthp_ are only changed if modify is true.
  bool FindBlobWidth(const std::vector<TBLOB *> &blobs, int index, bool modify);
 
  // Splits this blob into two blobs by applying the splits included in
  // *this SEAM
  void ApplySeam(bool italic_blob, TBLOB *blob, TBLOB *other_blob) const;
  // Undoes ApplySeam by removing the seam between these two blobs.
  // Produces one blob as a result, and deletes other_blob.
  void UndoSeam(TBLOB *blob, TBLOB *other_blob) const;
 
  // Prints everything in *this SEAM.
  void Print(const char *label) const;
  // Prints a collection of SEAMs.
  static void PrintSeams(const char *label, const std::vector<SEAM *> &seams);
#ifndef GRAPHICS_DISABLED
  // Draws the seam in the given window.
  void Mark(ScrollView *window) const;
#endif
 
  // Break up the blobs in this chain so that they are all independent.
  // This operation should undo the affect of join_pieces.
  static void BreakPieces(const std::vector<SEAM *> &seams, const std::vector<TBLOB *> &blobs,
                          int first, int last);
  // Join a group of base level pieces into a single blob that can then
  // be classified.
  static void JoinPieces(const std::vector<SEAM *> &seams, const std::vector<TBLOB *> &blobs,
                         int first, int last);
 
  // Hides the seam so the outlines appear not to be cut by it.
  void Hide() const;
  // Undoes hide, so the outlines are cut by the seam.
  void Reveal() const;
 
  // Computes and returns, but does not set, the full priority of *this SEAM.
  // The arguments here are config parameters defined in Wordrec. Add chop_
  // to the beginning of the name.
  float FullPriority(int xmin, int xmax, double overlap_knob, int centered_maxwidth,
                     double center_knob, double width_change_knob) const;
 
private:
  // Maximum number of splits that a SEAM can hold.
  static const uint8_t kMaxNumSplits = 3;
  // Priority of this split. Lower is better.
  float priority_;
  // Position of the middle of the seam.
  TPOINT location_;
  // A range such that all splits in *this SEAM are contained within blobs in
  // the range [index - widthn_,index + widthp_] where index is the index of
  // this SEAM in the seams vector.
  uint8_t widthp_ = 0;
  uint8_t widthn_ = 0;
  // Number of splits_ that are used.
  uint8_t num_splits_;
  // Set of pairs of points that are the ends of each split in the SEAM.
  SPLIT splits_[kMaxNumSplits];
};
 
void start_seam_list(TWERD *word, std::vector<SEAM *> *seam_array);
 
} // namespace tesseract
 
#endif