blobs.h

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/******************************************************************************
 *
 * File:        blobs.h
 * Description: Blob definition
 * Author:      Mark Seaman, OCR Technology
 *
 * (c) Copyright 1989, 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 BLOBS_H
#define BLOBS_H
 
#include "clst.h"       // for CLIST_ITERATOR, CLISTIZEH
#include "normalis.h"   // for DENORM
#include "points.h"     // for FCOORD, ICOORD
#include "rect.h"       // for TBOX
#include "scrollview.h" // for ScrollView, ScrollView::Color
 
#include <tesseract/publictypes.h> // for OcrEngineMode
 
#include "tesstypes.h" // for TDimension
 
struct Pix;
 
namespace tesseract {
 
class BLOCK;
class C_BLOB;
class C_OUTLINE;
class LLSQ;
class ROW;
class WERD;
 
/*----------------------------------------------------------------------
              T y p e s
----------------------------------------------------------------------*/
 
struct TPOINT {
  TPOINT() = default;
  TPOINT(TDimension vx, TDimension vy) : x(vx), y(vy) {}
  TPOINT(const ICOORD &ic) : x(ic.x()), y(ic.y()) {}
 
  void operator+=(const TPOINT &other) {
    x += other.x;
    y += other.y;
  }
  void operator/=(int divisor) {
    x /= divisor;
    y /= divisor;
  }
  bool operator==(const TPOINT &other) const {
    return x == other.x && y == other.y;
  }
  // Returns true when the two line segments cross each other.
  // (Moved from outlines.cpp).
  static bool IsCrossed(const TPOINT &a0, const TPOINT &a1, const TPOINT &b0, const TPOINT &b1);
 
  // Assign the difference from point p1 to point p2.
  void diff(const TPOINT &p1, const TPOINT &p2) {
    x = p1.x - p2.x;
    y = p1.y - p2.y;
  }
 
  // Return cross product.
  int cross(const TPOINT &other) const {
    return x * other.y - y * other.x;
  }
 
  // Return scalar or dot product.
  int dot(const TPOINT &other) const {
    return x * other.x + y * other.y;
  }
 
  // Calculate length of vector.
  int length() const {
    return x * x + y * y;
  }
 
  TDimension x = 0; // absolute x coord.
  TDimension y = 0; // absolute y coord.
};
 
using VECTOR = TPOINT; // structure for coordinates.
 
struct EDGEPT {
  EDGEPT() = default;
  EDGEPT(const EDGEPT &src) : next(nullptr), prev(nullptr) {
    CopyFrom(src);
  }
  EDGEPT &operator=(const EDGEPT &src) {
    CopyFrom(src);
    return *this;
  }
  // Copies the data elements, but leaves the pointers untouched.
  void CopyFrom(const EDGEPT &src) {
    pos = src.pos;
    vec = src.vec;
    is_hidden = src.is_hidden;
    runlength = src.runlength;
    dir = src.dir;
    fixed = src.fixed;
    src_outline = src.src_outline;
    start_step = src.start_step;
    step_count = src.step_count;
  }
  // Returns the squared distance between the points, with the x-component
  // weighted by x_factor.
  int WeightedDistance(const EDGEPT &other, int x_factor) const {
    int x_dist = pos.x - other.pos.x;
    int y_dist = pos.y - other.pos.y;
    return x_dist * x_dist * x_factor + y_dist * y_dist;
  }
  // Returns true if the positions are equal.
  bool EqualPos(const EDGEPT &other) const {
    return pos == other.pos;
  }
  // Returns the bounding box of the outline segment from *this to *end.
  // Ignores hidden edge flags.
  TBOX SegmentBox(const EDGEPT *end) const {
    TBOX box(pos.x, pos.y, pos.x, pos.y);
    const EDGEPT *pt = this;
    do {
      pt = pt->next;
      if (pt->pos.x < box.left()) {
        box.set_left(pt->pos.x);
      }
      if (pt->pos.x > box.right()) {
        box.set_right(pt->pos.x);
      }
      if (pt->pos.y < box.bottom()) {
        box.set_bottom(pt->pos.y);
      }
      if (pt->pos.y > box.top()) {
        box.set_top(pt->pos.y);
      }
    } while (pt != end && pt != this);
    return box;
  }
  // Returns the area of the outline segment from *this to *end.
  // Ignores hidden edge flags.
  int SegmentArea(const EDGEPT *end) const {
    int area = 0;
    const EDGEPT *pt = this->next;
    do {
      TPOINT origin_vec(pt->pos.x - pos.x, pt->pos.y - pos.y);
      area += origin_vec.cross(pt->vec);
      pt = pt->next;
    } while (pt != end && pt != this);
    return area;
  }
  // Returns true if the number of points in the outline segment from *this to
  // *end is less that min_points and false if we get back to *this first.
  // Ignores hidden edge flags.
  bool ShortNonCircularSegment(int min_points, const EDGEPT *end) const {
    int count = 0;
    const EDGEPT *pt = this;
    do {
      if (pt == end) {
        return true;
      }
      pt = pt->next;
      ++count;
    } while (pt != this && count <= min_points);
    return false;
  }
 
  // Accessors to hide or reveal a cut edge from feature extractors.
  void Hide() {
    is_hidden = true;
  }
  void Reveal() {
    is_hidden = false;
  }
  bool IsHidden() const {
    return is_hidden;
  }
  void MarkChop() {
    dir = 1;
  }
  bool IsChopPt() const {
    return dir != 0;
  }
 
  TPOINT pos; // position
  VECTOR vec; // vector to next point
  bool is_hidden = false;
  uint8_t runlength = 0;
  int8_t dir = 0;
  bool fixed = false;
  EDGEPT *next = nullptr;           // anticlockwise element
  EDGEPT *prev = nullptr;           // clockwise element
  C_OUTLINE *src_outline = nullptr; // Outline it came from.
  // The following fields are not used if src_outline is nullptr.
  int start_step = 0; // Location of pos in src_outline.
  int step_count = 0; // Number of steps used (may wrap around).
};
 
// For use in chop and findseam to keep a list of which EDGEPTs were inserted.
CLISTIZEH(EDGEPT)
 
struct TESSLINE {
  TESSLINE() : is_hole(false), loop(nullptr), next(nullptr) {}
  TESSLINE(const TESSLINE &src) : loop(nullptr), next(nullptr) {
    CopyFrom(src);
  }
  ~TESSLINE() {
    Clear();
  }
  TESSLINE &operator=(const TESSLINE &src) {
    CopyFrom(src);
    return *this;
  }
  // Consume the circular list of EDGEPTs to make a TESSLINE.
  static TESSLINE *BuildFromOutlineList(EDGEPT *outline);
  // Copies the data and the outline, but leaves next untouched.
  void CopyFrom(const TESSLINE &src);
  // Deletes owned data.
  void Clear();
  // Normalize in-place using the DENORM.
  void Normalize(const DENORM &denorm);
  // Rotates by the given rotation in place.
  void Rotate(const FCOORD rotation);
  // Moves by the given vec in place.
  void Move(const ICOORD vec);
  // Scales by the given factor in place.
  void Scale(float factor);
  // Sets up the start and vec members of the loop from the pos members.
  void SetupFromPos();
  // Recomputes the bounding box from the points in the loop.
  void ComputeBoundingBox();
  // Computes the min and max cross product of the outline points with the
  // given vec and returns the results in min_xp and max_xp. Geometrically
  // this is the left and right edge of the outline perpendicular to the
  // given direction, but to get the distance units correct, you would
  // have to divide by the modulus of vec.
  void MinMaxCrossProduct(const TPOINT vec, int *min_xp, int *max_xp) const;
 
  TBOX bounding_box() const;
  // Returns true if *this and other have equal bounding boxes.
  bool SameBox(const TESSLINE &other) const {
    return topleft == other.topleft && botright == other.botright;
  }
  // Returns true if the given line segment crosses any outline of this blob.
  bool SegmentCrosses(const TPOINT &pt1, const TPOINT &pt2) const {
    if (Contains(pt1) && Contains(pt2)) {
      EDGEPT *pt = loop;
      do {
        if (TPOINT::IsCrossed(pt1, pt2, pt->pos, pt->next->pos)) {
          return true;
        }
        pt = pt->next;
      } while (pt != loop);
    }
    return false;
  }
  // Returns true if the point is contained within the outline box.
  bool Contains(const TPOINT &pt) const {
    return topleft.x <= pt.x && pt.x <= botright.x && botright.y <= pt.y && pt.y <= topleft.y;
  }
 
#ifndef GRAPHICS_DISABLED
  void plot(ScrollView *window, ScrollView::Color color, ScrollView::Color child_color);
#endif // !GRAPHICS_DISABLED
 
  // Returns the first outline point that has a different src_outline to its
  // predecessor, or, if all the same, the lowest indexed point.
  EDGEPT *FindBestStartPt() const;
 
  int BBArea() const {
    return (botright.x - topleft.x) * (topleft.y - botright.y);
  }
 
  TPOINT topleft;  // Top left of loop.
  TPOINT botright; // Bottom right of loop.
  TPOINT start;    // Start of loop.
  bool is_hole;    // True if this is a hole/child outline.
  EDGEPT *loop;    // Edgeloop.
  TESSLINE *next;  // Next outline in blob.
};                 // Outline structure.
 
struct TBLOB {
  TBLOB() : outlines(nullptr) {}
  TBLOB(const TBLOB &src) : outlines(nullptr) {
    CopyFrom(src);
  }
  ~TBLOB() {
    Clear();
  }
  TBLOB &operator=(const TBLOB &src) {
    CopyFrom(src);
    return *this;
  }
  // Factory to build a TBLOB from a C_BLOB with polygonal approximation along
  // the way. If allow_detailed_fx is true, the EDGEPTs in the returned TBLOB
  // contain pointers to the input C_OUTLINEs that enable higher-resolution
  // feature extraction that does not use the polygonal approximation.
  static TBLOB *PolygonalCopy(bool allow_detailed_fx, C_BLOB *src);
  // Factory builds a blob with no outlines, but copies the other member data.
  static TBLOB *ShallowCopy(const TBLOB &src);
  // Normalizes the blob for classification only if needed.
  // (Normally this means a non-zero classify rotation.)
  // If no Normalization is needed, then nullptr is returned, and the input blob
  // can be used directly. Otherwise a new TBLOB is returned which must be
  // deleted after use.
  TBLOB *ClassifyNormalizeIfNeeded() const;
 
  // Copies the data and the outlines, but leaves next untouched.
  void CopyFrom(const TBLOB &src);
  // Deletes owned data.
  void Clear();
  // Sets up the built-in DENORM and normalizes the blob in-place.
  // For parameters see DENORM::SetupNormalization, plus the inverse flag for
  // this blob and the Pix for the full image.
  void Normalize(const BLOCK *block, const FCOORD *rotation, const DENORM *predecessor,
                 float x_origin, float y_origin, float x_scale, float y_scale, float final_xshift,
                 float final_yshift, bool inverse, Image pix);
  // Rotates by the given rotation in place.
  void Rotate(const FCOORD rotation);
  // Moves by the given vec in place.
  void Move(const ICOORD vec);
  // Scales by the given factor in place.
  void Scale(float factor);
  // Recomputes the bounding boxes of the outlines.
  void ComputeBoundingBoxes();
 
  // Returns the number of outlines.
  int NumOutlines() const;
 
  TBOX bounding_box() const;
 
  // Returns true if the given line segment crosses any outline of this blob.
  bool SegmentCrossesOutline(const TPOINT &pt1, const TPOINT &pt2) const {
    for (const TESSLINE *outline = outlines; outline != nullptr; outline = outline->next) {
      if (outline->SegmentCrosses(pt1, pt2)) {
        return true;
      }
    }
    return false;
  }
  // Returns true if the point is contained within any of the outline boxes.
  bool Contains(const TPOINT &pt) const {
    for (const TESSLINE *outline = outlines; outline != nullptr; outline = outline->next) {
      if (outline->Contains(pt)) {
        return true;
      }
    }
    return false;
  }
 
  // Finds and deletes any duplicate outlines in this blob, without deleting
  // their EDGEPTs.
  void EliminateDuplicateOutlines();
 
  // Swaps the outlines of *this and next if needed to keep the centers in
  // increasing x.
  void CorrectBlobOrder(TBLOB *next);
 
  const DENORM &denorm() const {
    return denorm_;
  }
 
#ifndef GRAPHICS_DISABLED
  void plot(ScrollView *window, ScrollView::Color color, ScrollView::Color child_color);
#endif // !GRAPHICS_DISABLED
 
  int BBArea() const {
    int total_area = 0;
    for (TESSLINE *outline = outlines; outline != nullptr; outline = outline->next) {
      total_area += outline->BBArea();
    }
    return total_area;
  }
 
  // Computes the center of mass and second moments for the old baseline and
  // 2nd moment normalizations. Returns the outline length.
  // The input denorm should be the normalizations that have been applied from
  // the image to the current state of this TBLOB.
  int ComputeMoments(FCOORD *center, FCOORD *second_moments) const;
  // Computes the precise bounding box of the coords that are generated by
  // GetEdgeCoords. This may be different from the bounding box of the polygon.
  void GetPreciseBoundingBox(TBOX *precise_box) const;
  // Adds edges to the given vectors.
  // For all the edge steps in all the outlines, or polygonal approximation
  // where there are no edge steps, collects the steps into x_coords/y_coords.
  // x_coords is a collection of the x-coords of vertical edges for each
  // y-coord starting at box.bottom().
  // y_coords is a collection of the y-coords of horizontal edges for each
  // x-coord starting at box.left().
  // Eg x_coords[0] is a collection of the x-coords of edges at y=bottom.
  // Eg x_coords[1] is a collection of the x-coords of edges at y=bottom + 1.
  void GetEdgeCoords(const TBOX &box, std::vector<std::vector<int>> &x_coords,
                     std::vector<std::vector<int>> &y_coords) const;
 
  TESSLINE *outlines; // List of outlines in blob.
 
private: // TODO(rays) Someday the data members will be private too.
  // For all the edge steps in all the outlines, or polygonal approximation
  // where there are no edge steps, collects the steps into the bounding_box,
  // llsq and/or the x_coords/y_coords. Both are used in different kinds of
  // normalization.
  // For a description of x_coords, y_coords, see GetEdgeCoords above.
  void CollectEdges(const TBOX &box, TBOX *bounding_box, LLSQ *llsq,
                    std::vector<std::vector<int>> *x_coords,
                    std::vector<std::vector<int>> *y_coords) const;
 
private:
  // DENORM indicating the transformations that this blob has undergone so far.
  DENORM denorm_;
}; // Blob structure.
 
struct TWERD {
  TWERD() : latin_script(false) {}
  TWERD(const TWERD &src) {
    CopyFrom(src);
  }
  ~TWERD() {
    Clear();
  }
  TWERD &operator=(const TWERD &src) {
    CopyFrom(src);
    return *this;
  }
  // Factory to build a TWERD from a (C_BLOB) WERD, with polygonal
  // approximation along the way.
  static TWERD *PolygonalCopy(bool allow_detailed_fx, WERD *src);
  // Baseline normalizes the blobs in-place, recording the normalization in the
  // DENORMs in the blobs.
  void BLNormalize(const BLOCK *block, const ROW *row, Image pix, bool inverse, float x_height,
                   float baseline_shift, bool numeric_mode, tesseract::OcrEngineMode hint,
                   const TBOX *norm_box, DENORM *word_denorm);
  // Copies the data and the blobs, but leaves next untouched.
  void CopyFrom(const TWERD &src);
  // Deletes owned data.
  void Clear();
  // Recomputes the bounding boxes of the blobs.
  void ComputeBoundingBoxes();
 
  // Returns the number of blobs in the word.
  unsigned NumBlobs() const {
    return blobs.size();
  }
  TBOX bounding_box() const;
 
  // Merges the blobs from start to end, not including end, and deletes
  // the blobs between start and end.
  void MergeBlobs(unsigned start, unsigned end);
 
#ifndef GRAPHICS_DISABLED
  void plot(ScrollView *window);
#endif // !GRAPHICS_DISABLED
 
  std::vector<TBLOB *> blobs; // Blobs in word.
  bool latin_script;          // This word is in a latin-based script.
};
 
/*----------------------------------------------------------------------
              F u n c t i o n s
----------------------------------------------------------------------*/
// TODO(rays) Make divisible_blob and divide_blobs members of TBLOB.
bool divisible_blob(TBLOB *blob, bool italic_blob, TPOINT *location);
 
void divide_blobs(TBLOB *blob, TBLOB *other_blob, bool italic_blob, const TPOINT &location);
 
} // namespace tesseract
 
#endif