vpFloodFill.cpp

/****************************************************************************
 *
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2019 by Inria. All rights reserved.
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 * it under the terms of the GNU General Public License as published by
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 * Description:
 * Flood fill algorithm.
 *
 * Authors:
 * Souriya Trinh
 *
 *****************************************************************************/
/*
 * Copyright (c) 2004-2007, Lode Vandevenne
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *    * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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 */

#include <queue>
#include <visp3/imgproc/vpImgproc.h>

void vp::floodFill(vpImage<unsigned char> &I, const vpImagePoint &seedPoint, const unsigned char oldValue,
                   const unsigned char newValue, const vpImageMorphology::vpConnexityType &connexity)
{
  // Code from Lode Vandevenne tutorial.
  // Naive modification for 8-connexity implementation
  if (oldValue == newValue || I.getSize() == 0) {
    return;
  }

  std::queue<vpImagePoint> seed_queue;

  // Add initial seed point
  seed_queue.push(seedPoint);

  while (!seed_queue.empty()) {
    vpImagePoint current_seed = seed_queue.front();
    seed_queue.pop();

    unsigned int x = (unsigned int)current_seed.get_j();
    unsigned int y = (unsigned int)current_seed.get_i();
    int x1 = (int)x;

    // Find most left pixel
    while (x1 >= 0 && I[y][x1] == oldValue) {
      x1--;
    }
    x1++;

    bool spanAbove = false, spanBelow = false;

    while (x1 < (int)I.getWidth() && I[y][x1] == oldValue) {
      I[y][x1] = newValue;

      if (!spanAbove && y > 0) {
        if (I[y - 1][x1] == oldValue) {
          // North
          spanAbove = true;
          seed_queue.push(vpImagePoint(y - 1, x1));
        }

        if (connexity != vpImageMorphology::CONNEXITY_4) {
          if (x1 > 0 && I[y - 1][x1 - 1] == oldValue) {
            // North west
            spanAbove = true;
            seed_queue.push(vpImagePoint(y - 1, x1 - 1));
          }
          if (x1 < (int)I.getWidth() - 1 && I[y - 1][x1 + 1] == oldValue) {
            // North east
            spanAbove = true;
            seed_queue.push(vpImagePoint(y - 1, x1 + 1));
          }
        }
      } else if (spanAbove && y > 0 && I[y - 1][x1] != oldValue) {
        spanAbove = false;
      }

      if (!spanBelow && y < I.getHeight() - 1) {
        if (I[y + 1][x1] == oldValue) {
          // South
          seed_queue.push(vpImagePoint(y + 1, x1));
          spanBelow = true;
        }

        if (connexity != vpImageMorphology::CONNEXITY_4) {
          if (x1 > 0 && I[y + 1][x1 - 1] == oldValue) {
            // South west
            seed_queue.push(vpImagePoint(y + 1, x1 - 1));
            spanBelow = true;
          }
          if (x1 < (int)I.getWidth() - 1 && I[y + 1][x1 + 1] == oldValue) {
            // South east
            seed_queue.push(vpImagePoint(y + 1, x1 + 1));
            spanBelow = true;
          }
        }
      } else if (spanBelow && y < I.getHeight() - 1 && I[y + 1][x1] != oldValue) {
        spanBelow = false;
      }

      // TODO: improve 8-connexity
      if (connexity != vpImageMorphology::CONNEXITY_4) {
        spanBelow = false;
        spanAbove = false;
      }

      x1++;
    }
  }
}