stepblob.h

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/**********************************************************************
 * File:        stepblob.h  (Formerly cblob.h)
 * Description: Code for C_BLOB class.
 * Author:      Ray Smith
 * Created:     Tue Oct 08 10:41:13 BST 1991
 *
 * (C) Copyright 1991, 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.
 *
 **********************************************************************/
 
#ifndef STEPBLOB_H
#define STEPBLOB_H
 
#include "coutln.h"     // for C_OUTLINE_LIST, C_OUTLINE
#include "elst.h"       // for ELIST_ITERATOR, ELISTIZEH, ELIST_LINK
#include "points.h"     // for FCOORD, ICOORD (ptr only)
#include "rect.h"       // for TBOX
#include "scrollview.h" // for ScrollView, ScrollView::Color
 
#include <cstdint> // for int32_t, int16_t
 
struct Pix;
 
namespace tesseract {
 
class C_BLOB;
class DENORM;
 
ELISTIZEH(C_BLOB)
 
class TESS_API C_BLOB : public ELIST_LINK {
public:
  C_BLOB() = default;
  explicit C_BLOB(C_OUTLINE_LIST *outline_list);
  // Simpler constructor to build a blob from a single outline that has
  // already been fully initialized.
  explicit C_BLOB(C_OUTLINE *outline);
 
  // Builds a set of one or more blobs from a list of outlines.
  // Input: one outline on outline_list contains all the others, but the
  // nesting and order are undefined.
  // If good_blob is true, the blob is added to good_blobs_it, unless
  // an illegal (generation-skipping) parent-child relationship is found.
  // If so, the parent blob goes to bad_blobs_it, and the immediate children
  // are promoted to the top level, recursively being sent to good_blobs_it.
  // If good_blob is false, all created blobs will go to the bad_blobs_it.
  // Output: outline_list is empty. One or more blobs are added to
  // good_blobs_it and/or bad_blobs_it.
  static void ConstructBlobsFromOutlines(bool good_blob, C_OUTLINE_LIST *outline_list,
                                         C_BLOB_IT *good_blobs_it, C_BLOB_IT *bad_blobs_it);
 
  // Sets the COUT_INVERSE flag appropriately on the outlines and their
  // children recursively, reversing the outlines if needed so that
  // everything has an anticlockwise top-level.
  void CheckInverseFlagAndDirection();
 
  // Build and return a fake blob containing a single fake outline with no
  // steps.
  static C_BLOB *FakeBlob(const TBOX &box);
 
  C_OUTLINE_LIST *out_list() { // get outline list
    return &outlines;
  }
 
  TBOX bounding_box() const; // compute bounding box
  int32_t area();            // compute area
  int32_t perimeter();       // Total perimeter of outlines and 1st level children.
  int32_t outer_area();      // compute area
  int32_t count_transitions( // count maxima
      int32_t threshold);    // size threshold
 
  void move(const ICOORD vec);         // reposition blob by vector
  void rotate(const FCOORD &rotation); // Rotate by given vector.
 
  // Adds sub-pixel resolution EdgeOffsets for the outlines using greyscale
  // if the supplied pix is 8-bit or the binary edges if nullptr.
  void ComputeEdgeOffsets(int threshold, Image pix);
 
  // Estimates and returns the baseline position based on the shape of the
  // outlines.
  int16_t EstimateBaselinePosition();
 
  // Returns a Pix rendering of the blob. pixDestroy after use.
  Image render();
  // Returns a Pix rendering of the outline of the blob. (no fill).
  // pixDestroy after use.
  Image render_outline();
 
#ifndef GRAPHICS_DISABLED
  void plot(                           // draw one
      ScrollView *window,              // window to draw in
      ScrollView::Color blob_colour,   // for outer bits
      ScrollView::Color child_colour); // for holes
  // Draws the blob in the given colour, and child_colour, normalized
  // using the given denorm, making use of sub-pixel accurate information
  // if available.
  void plot_normed(const DENORM &denorm, ScrollView::Color blob_colour,
                   ScrollView::Color child_colour, ScrollView *window);
#endif // !GRAPHICS_DISABLED
 
  C_BLOB &operator=(const C_BLOB &source) {
    if (!outlines.empty()) {
      outlines.clear();
    }
    outlines.deep_copy(&source.outlines, &C_OUTLINE::deep_copy);
    return *this;
  }
 
  static C_BLOB *deep_copy(const C_BLOB *src) {
    auto *blob = new C_BLOB;
    *blob = *src;
    return blob;
  }
 
  static int SortByXMiddle(const void *v1, const void *v2) {
    const C_BLOB *blob1 = *static_cast<const C_BLOB *const *>(v1);
    const C_BLOB *blob2 = *static_cast<const C_BLOB *const *>(v2);
    return blob1->bounding_box().x_middle() - blob2->bounding_box().x_middle();
  }
 
private:
  C_OUTLINE_LIST outlines; // master elements
};
 
} // namespace tesseract
 
#endif