#include "tcenterlinevectP.h"

//==========================================================================

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

//*    Polygonization    *

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

//--------------------------------------------------------------------------

//===============================

//    Raw Borders Extraction

//===============================

// Raw contour class definition

class RawBorderPoint {

  TPoint m_position;

  int m_ambiguousTurn;  // used to remember cases of multiple turning directions

  // in a RawBorder extraction.

public:

  RawBorderPoint() : m_ambiguousTurn(0) {}

  RawBorderPoint(int i, int j) : m_position(i, j), m_ambiguousTurn(0) {}

  inline TPoint pos() const { return m_position; }

  inline int x() const { return m_position.x; }

  inline int y() const { return m_position.y; }

  enum { left = 1, right = 2 };  // Direction taken at ambiguous turning point

  inline int getAmbiguous() const { return m_ambiguousTurn; }

  inline void setAmbiguous(int direction) { m_ambiguousTurn = direction; }

};

//--------------------------------------------------------------------------

class RawBorder final : public std::vector<rawborderpoint> {</rawborderpoint>

  int m_xExternal;  // x coordinate of a specific vertex in the outer

  // RawBorder which contains this inner one.

  TPointD *m_coordinateSums;

  TPointD *m_coordinateSquareSums;

  double *m_coordinateMixedSums;

public:

  RawBorder() {}

  ~RawBorder() {}

  void setXExternalPixel(int a) { m_xExternal = a; }

  int xExternalPixel() { return m_xExternal; }

  TPointD *&sums() { return m_coordinateSums; }

  TPointD *&sums2() { return m_coordinateSquareSums; }

  double *&sumsMix() { return m_coordinateMixedSums; }

};

//--------------------------------------------------------------------------

// Of course we don't want RawBorders to be entirely copied whenever STL

// requires to resize a BorderFamily...

typedef std::vector<rawborder *=""> BorderFamily;</rawborder>

typedef std::vector<borderfamily> BorderList;</borderfamily>

//--------------------------------------------------------------------------

//==========================================================================

//============================

//    Polygonizer Locals

//============================

namespace {

// Const names

enum { white = 0, black = 1 };

enum { inner = 0, outer = 1, none = 2, invalid = 3 };

}

//=======================================================================================

//-------------------------------

//    Raster Data Functions

//-------------------------------

// NOTA: Il tono di un TPixelCM32 rappresenta la transizione tra colore ink e

// colore paint.

//      di solito, se il tono e' basso abbiamo un colore ink - che puo' anche

//      essere bianco,

//      in teoria...

//      Sarebbe opportuno che il vettorizzatore riconoscesse - per colormap - il

//      colore

//      delle strokes.

//      Approcci: a)  la Signaturemap diventa *piu'* di una bitmap e si seguono

//      le outline

//                    dei singoli colori.

//                 => Sconnessioni tra i colori adiacenti. Bisogna introdurre la

//                 distanza tra

//                    colori per seguire l'outline (ossia, i pixel tenuti a dx

//                    della outline

//                    devono essere simili).

//

//                b)  Una volta vettorizzato tutto, si sceglie il colore della

//                stroke.

//                    E' possibile controllare il colore sui vertici delle

//                    sequenze semplificate

//                    e fare una media.

// NOTE: Transparency makes colors fade to white. Full transparent black pixels

// are considered white.

//--------------------------------------------------------------------------

template <typename t=""></typename>

class PixelEvaluator {

  TRasterPT<t> m_ras;</t>

  int m_threshold;

public:

  PixelEvaluator(const TRasterPT<t> &ras, int threshold)</t>

      : m_ras(ras), m_threshold(threshold) {}

  inline unsigned char getBlackOrWhite(int x, int y);

};

//--------------------------------------------------------------------------

template <>

inline unsigned char PixelEvaluator<tpixel32>::getBlackOrWhite(int x, int y) {</tpixel32>

  // return ras->pixels(y)[x].r + 2 * ras->pixels(y)[x].g + ras->pixels(y)[x].b

  // <

  //   threshold * (ras->pixels(y)[x].m / 255.0);

  // NOTE: Green is considered twice brighter than red or blue channel.

  // Using Value of HSV color model

  return std::max(m_ras->pixels(y)[x].r,

                  std::max(m_ras->pixels(y)[x].g, m_ras->pixels(y)[x].b)) <

         m_threshold * (m_ras->pixels(y)[x].m / 255.0);

  // Using Lightness of HSV color model

  // return (max(ras->pixels(y)[x].r, max(ras->pixels(y)[x].g,

  // ras->pixels(y)[x].b)) +

  //       min(ras->pixels(y)[x].r, min(ras->pixels(y)[x].g,

  //       ras->pixels(y)[x].b))) / 2.0 <

  //  threshold * (ras->pixels(y)[x].m / 255.0);

  // Using (relative) Luminance

  // return 0.2126 * ras->pixels(y)[x].r + 0.7152 * ras->pixels(y)[x].g + 0.0722

  // * ras->pixels(y)[x].b <

  //  threshold * (ras->pixels(y)[x].m / 255.0);

}

template <>

inline unsigned char PixelEvaluator<tpixelgr8>::getBlackOrWhite(int x, int y) {</tpixelgr8>

  return m_ras->pixels(y)[x].value < m_threshold;

}

template <>

inline unsigned char PixelEvaluator<tpixelcm32>::getBlackOrWhite(int x, int y) {</tpixelcm32>

  return m_ras->pixels(y)[x].getTone() < m_threshold;

}

//--------------------------------------------------------------------------

// Signaturemap format:

//  stores a map of bytes, whose first bit represents the color (black/white) of

//  corresponding pixel, and

//  the rest its 'signature', used as an int to store information.

// NOTE: given a TRaster32, the corresponding Signaturemap constructed is

// intended 0(white)-padded

class Signaturemap {

  std::unique_ptr<unsigned char[]=""> m_array;</unsigned>

  int m_rowSize;

  int m_colSize;

public:

  Signaturemap(const TRasterP &ras, int threshold);

  template <typename t=""></typename>

  void readRasterData(const TRasterPT<t> &ras, int threshold);</t>

  inline int getRowSize() const { return m_rowSize; }

  inline int getColSize() const { return m_colSize; }

  unsigned char *pixelByte(int x, int y) {

    return &m_array[(y + 1) * m_rowSize + x + 1];

  }

  bool getBitmapColor(int x, int y) const {

    return m_array[(y + 1) * m_rowSize + x + 1] & 1;

  }

  inline unsigned char getSignature(int x, int y) const {

    return m_array[(y + 1) * m_rowSize + x + 1] >> 1;

  }

  void setSignature(int x, int y, int val) {

    unsigned char *pixel = pixelByte(x, y);

    *pixel &= 1;

    *pixel |= (val << 1);  // Si puo' fare meglio??

  }

};

//--------------------------------------------------------------------------

Signaturemap::Signaturemap(const TRasterP &ras, int threshold) {

  // Extrapolate raster type

  TRaster32P rr   = (TRaster32P)ras;

  TRasterGR8P rgr = (TRasterGR8P)ras;

  TRasterCM32P rt = (TRasterCM32P)ras;

  assert(rr || rgr || rt);

  // Read raster data

  if (rr) {

    rr->lock();

    readRasterData(rr, threshold);

    rr->unlock();

  } else if (rgr) {

    rgr->lock();

    readRasterData(rgr, threshold);

    rgr->unlock();

  } else {

    rt->lock();

    readRasterData(rt, threshold);

    rt->unlock();

  }

}

//--------------------------------------------------------------------------

template <typename t=""></typename>

void Signaturemap::readRasterData(const TRasterPT<t> &ras, int threshold) {</t>

  unsigned char *currByte;

  int x, y;

  PixelEvaluator<t> evaluator(ras, threshold);</t>

  m_rowSize = ras->getLx() + 2;

  m_colSize = ras->getLy() + 2;

  m_array.reset(new unsigned char[m_rowSize * m_colSize]);

  memset(m_array.get(), none << 1, m_rowSize);

  currByte = m_array.get() + m_rowSize;

  for (y = 0; y < ras->getLy(); ++y) {

    *currByte = none << 1;

    currByte++;

    for (x = 0; x < ras->getLx(); ++x, ++currByte)

      *currByte = evaluator.getBlackOrWhite(x, y) | (none << 1);

    *currByte = none << 1;

    currByte++;

  }

  memset(currByte, none << 1, m_rowSize);

}

//--------------------------------------------------------------------------

// Minority check for amiguous turning directions

inline bool getMinorityCheck(const Signaturemap &ras, int x, int y) {

  // Assumes (x,y) is ambiguous case: 2 immediate surrounding pixels are white

  // and 2 black

  return (ras.getBitmapColor(x + 1, y) + ras.getBitmapColor(x + 1, y - 1) +

          ras.getBitmapColor(x - 2, y) + ras.getBitmapColor(x - 2, y - 1) +

          ras.getBitmapColor(x - 1, y + 1) + ras.getBitmapColor(x - 1, y - 2) +

          ras.getBitmapColor(x, y + 1) + ras.getBitmapColor(x, y - 2)) > 4;

}

//--------------------------------------------------------------------------

// Sets signature of a given border

inline void setSignature(Signaturemap &ras, const RawBorder &border, int val) {

  unsigned int j;

  int yOld;

  // Set border's alpha channel

  yOld = border.back().y();

  for (j = 0; j < border.size(); ++j) {

    if (border[j].y() < yOld) {

      ras.setSignature(border[j].x(), border[j].y(), val);

    } else if (border[j].y() > yOld) {

      ras.setSignature(border[j].x(), yOld, val);

    }

    yOld = border[j].y();

  }

}

//==========================================================================

//-------------------------------

//    Raw Borders Extraction

//-------------------------------

// RawBorderPoints correspond to lower-left pixel corners.

// EXAMPLE: (0,0) is the lower-left *corner* of the image, whereas (0,0) also

// represents coordinates of the lower-left *pixel*.

// NOTE: 'Ambiguous turning' vertices are those of kind:

//

//    B|W           W|B

//    -x-    -or-   -x-

//    W|B           B|W

//

// Keeping B on the right of our path-seeking direction, we may either turn

// left or right at these points.

RawBorder *extractPath(Signaturemap &ras, int x0, int y0, int pathType,

                       int xOuterPixel, int despeckling) {

  RawBorder *path = new RawBorder;

  int x, y;

  short dirX, dirY;

  long int area = 0;

  bool nextLeftPixel, nextRightPixel;

  if (pathType == outer) {

    dirX = 0;

    dirY = 1;

  } else {

    dirX = 1;

    dirY = 0;

    area += y0;

    path->setXExternalPixel(xOuterPixel);

  }

  path->push_back(RawBorderPoint(x0, y0));

  // Check here if (x0, y0) is an ambiguous-direction point

  nextLeftPixel = ras.getBitmapColor(x0 + (dirY - dirX - 1) / 2,

                                     y0 + (-dirY - dirX - 1) / 2);

  nextRightPixel = ras.getBitmapColor(x0 + (-dirX - dirY - 1) / 2,

                                      y0 + (dirX - dirY - 1) / 2);

  if ((nextRightPixel == black) && (nextLeftPixel == white))

    path->back().setAmbiguous(dirX ? RawBorderPoint::left

                                   : RawBorderPoint::right);

  // Begin path extraction

  for (x = x0 + dirX, y = y0 + dirY; !(x == x0 && y == y0);

       x += dirX, y += dirY) {

    path->push_back(RawBorderPoint(x, y));

    // Calculate next direction

    nextLeftPixel = ras.getBitmapColor(x + (dirX - dirY - 1) / 2,

                                       y + (dirY + dirX - 1) / 2);

    nextRightPixel = ras.getBitmapColor(x + (dirX + dirY - 1) / 2,

                                        y + (dirY - dirX - 1) / 2);

    if ((nextRightPixel == black) && (nextLeftPixel == black)) {

      // Left Turn

      std::swap(dirY, dirX);

      dirX = -dirX;

    } else if ((nextRightPixel == white) && (nextLeftPixel == white)) {

      // Right Turn

      std::swap(dirY, dirX);

      dirY = -dirY;

    } else if ((nextRightPixel == white) && (nextLeftPixel == black)) {

      // path->back().setAmbiguous();

      // Do a surrounding check and connect minority color

      if (getMinorityCheck(ras, x, y) == black) {

        std::swap(dirY, dirX);

        dirY = -dirY;

        path->back().setAmbiguous(RawBorderPoint::right);

      }  // right turn

      else {

        std::swap(dirY, dirX);

        dirX = -dirX;

        path->back().setAmbiguous(RawBorderPoint::left);

      }  // left turn

    }

    // Also calculate border area

    area += y * dirX;

    // And sign treated pixel

    if (dirY != 0) ras.setSignature(x, y + (dirY - 1) / 2, pathType);

  }

  // If the inner region's overall area is under a given threshold,

  // then erase it (intended as image noise).

  if (abs(area) < despeckling) {

    setSignature(ras, *path, invalid);

    delete path;

    path = 0;

  }

  return path;

}

//--------------------------------------------------------------------------

BorderList *extractBorders(const TRasterP &ras, int threshold,

                           int despeckling) {

  Signaturemap byteImage(ras, threshold);

  BorderList *borderHierarchy = new BorderList;

  std::vector<rawborder *=""> outerBorders;</rawborder>

  std::list<rawborder *=""> innerBorders;</rawborder>

  RawBorder *foundPath;

  int x, y;

  bool Color, oldColor;

  int xOuterPixel = 0;

  bool enteredRegionType;

  unsigned char signature;

  // Traverse image to extract raw borders

  for (y = 0; y < ras->getLy(); ++y) {

    oldColor          = white;

    enteredRegionType = outer;

    for (x = 0; x < ras->getLx(); ++x) {

      if (oldColor ^ (Color = byteImage.getBitmapColor(x, y))) {

        // Region type changes

        enteredRegionType = !enteredRegionType;

        if ((signature = byteImage.getSignature(x, y)) == none) {

          // We've found a border

          if ((foundPath = extractPath(byteImage, x, y, !enteredRegionType,

                                       xOuterPixel, despeckling)))

            if (enteredRegionType == outer)

              innerBorders.push_back(foundPath);

            else

              outerBorders.push_back(foundPath);

        }

        // If leaving a white region, remember it - in order to establish

        // border hierarchy in the future

        if (enteredRegionType == inner && signature != invalid) xOuterPixel = x;

        // Invalid pixels got signed by a cut-out path, due to insufficient area

        if (signature == invalid)

          byteImage.setSignature(x, y, none);  // Restore them now

        oldColor = Color;

      }

    }

  }

  // Now, we have all borders found, but no hierarchy between them.

  unsigned int i;

  std::list<rawborder *="">::iterator l;</rawborder>

  // Build hierarchy

  innerBorders.push_front(0);  // Just to keep a fixed list head

  for (i = 0; i < outerBorders.size(); ++i) {

    // Initialize a border family

    borderHierarchy->push_back(BorderFamily());

    borderHierarchy->back().push_back(outerBorders[i]);

    // Reset outerBorders[i]'s signature

    setSignature(byteImage, *outerBorders[i], none);

    // Now check inner borders for insideness - check if the outerPixel

    // remembered in path extraction has been cleared

    for (l = innerBorders.begin(), ++l; l != innerBorders.end(); ++l) {

      if (byteImage.getSignature((*l)->xExternalPixel(), (**l)[0].y()) ==

          none) {

        borderHierarchy->back().push_back(*l);

        setSignature(byteImage, **l, none);

        l = innerBorders.erase(l);

        --l;

      }

    }

  }

  return borderHierarchy;

}

//--------------------------------------------------------------------------

//==================================

//    Calculate optimal polygons

//==================================

// The optimal polygon for a given original border is found like:

// 1) Find couples (i,k(i)), so that k(i) be the largest k:

//        d(j,ik) <= 1;  for *all* i

//    It can be shown that such a condition is equivalent to:

//      exists line l : d(l,j)<=1/2, for all i<=j<=k(i).

// 2) Clean the above couples - find couples (i,l(i)):

//        l(i)=min{k(j)},  j=i..n.

// 3) Calculate clipped couples (i',l'); where i'=i+1, l'=l(i)-1.

// 4) Calculate sums for path penalties.

// 5) Apply optimality algorithm.

// NOTE: Weak simpleness reads like: a set of polygons is weak-simple if no edge

//      *crosses* another edge. Superposition and collision of edges with

//      vertices

//      are still admitted.

//        =>  It can be shown that due to 1) and special conditions on ambiguous

//            turnings applied in both 1) and 3), weak simpleness is insured in

//            our polygonization.

//--------------------------------------------------------------------------

// Helper functions/classes: circular-indexed vectors

// returns 1 whenever the triple (a,b,c) is 'circular' mod n.

// NOTE: We'll find useful taking (i,i,j) as 1 and (i,j,j) as 0.

inline bool isCircular(int a, int b, int c) {

  return a <= c ? a <= b && b < c : c > b || b >= a;

}

//--------------------------------------------------------------------------

// Extracts a 'next corner' array - helps improving overall speed

inline std::unique_ptr<int[]> findNextCorners(RawBorder &path) {</int[]>

  std::unique_ptr<int[]> corners(new int[path.size()]);</int[]>

  // NOTE: 0 is a corner, due to the path extraction procedure.

  int currentCorner = 0;

  for (int i = path.size() - 1; i >= 0; --i) {

    if (path[currentCorner].x() != path[i].x() &&

        path[currentCorner].y() != path[i].y())

      currentCorner = i + 1;

    corners[i]      = currentCorner;

  }

  return corners;

}

//--------------------------------------------------------------------------

// Calculate furthest k satisfying 1) for all fixed i.

inline std::unique_ptr<int[]> furthestKs(RawBorder &path,</int[]>

                                         std::unique_ptr<int[]> &nextCorners) {</int[]>

  int n = path.size();

  std::unique_ptr<int[]> kVector(new int[n]);</int[]>

  enum { left, up, right, down };

  int directionsOccurred[4];

  nextCorners = findNextCorners(path);

  int i, j, k;

  TPoint shift;

  TPoint leftConstraint, rightConstraint, violatedConstraint;

  TPoint newLeftConstraint, newRightConstraint;

  TPoint jPoint, jNextPoint, iPoint, direction;

  int directionSignature;

  for (i = 0; i < n; ++i) {

    // Initialize search

    leftConstraint = rightConstraint = TPoint();

    directionsOccurred[0] = directionsOccurred[1] = directionsOccurred[2] =

        directionsOccurred[3]                     = 0;

    j                                             = i;

    jNextPoint = iPoint = path[i].pos();

    // Search for k(i)

    while (1) {

      // NOTE: Here using TPoint::operator= is less effective than setting

      // its x and y components directly...

      jPoint     = jNextPoint;

      jNextPoint = path[nextCorners[j]].pos();

      // Update directions count

      directionSignature = jNextPoint.x > jPoint.x

                               ? right

                               : jNextPoint.x < jPoint.x

                                     ? left

                                     : jNextPoint.y > jPoint.y ? up : down;

      directionsOccurred[directionSignature] = 1;

      // If all 4 axis directions occurred, quit

      if (directionsOccurred[left] && directionsOccurred[right] &&

          directionsOccurred[up] && directionsOccurred[down]) {

        k = j;

        goto foundK;

      }

      // Update displacement from i

      shift = jNextPoint - iPoint;

      // Test j against constraints

      // if(cross(shift, leftConstraint)<0 || cross(shift, rightConstraint)>0)

      if (cross(shift, leftConstraint) < 0) {

        violatedConstraint = leftConstraint;

        break;

      }

      if (cross(shift, rightConstraint) > 0) {

        violatedConstraint = rightConstraint;

        break;

      }

      // Update constraints

      if (abs(shift.x) > 1 || abs(shift.y) > 1) {

        newLeftConstraint.x =

            shift.x + (shift.y < 0 || (shift.y == 0 && shift.x < 0) ? 1 : -1);

        newLeftConstraint.y =

            shift.y + (shift.x > 0 || (shift.x == 0 && shift.y < 0) ? 1 : -1);

        if (cross(newLeftConstraint, leftConstraint) >= 0)

          leftConstraint = newLeftConstraint;

        newRightConstraint.x =

            shift.x + (shift.y > 0 || (shift.y == 0 && shift.x < 0) ? 1 : -1);

        newRightConstraint.y =

            shift.y + (shift.x < 0 || (shift.x == 0 && shift.y < 0) ? 1 : -1);

        if (cross(newRightConstraint, rightConstraint) <= 0)

          rightConstraint = newRightConstraint;

      }

      // Imposing strict constraint for ambiguous turnings, to ensure polygons'

      // weak simpleness.

      // Has to be defined *outside* abs checks.

      if (path[nextCorners[j]].getAmbiguous()) {

        if (path[nextCorners[j]].getAmbiguous() == RawBorderPoint::left)

          rightConstraint = shift;

        else

          leftConstraint = shift;

      }

      j = nextCorners[j];

    }

    // At this point, constraints are violated by the next corner.

    // Then, search for the last k between j and corners[j] not violating them.

    direction = convert(normalize(convert(jNextPoint - jPoint)));

    k         = (j +

         cross(jPoint - iPoint, violatedConstraint) /

             cross(violatedConstraint, direction)) %

        n;

  foundK:

    kVector[i] = k;

  }

  return kVector;

}

//--------------------------------------------------------------------------

// Now find the effective intervals inside which we can define possible

// arcs approximating the given raw border:

//    for every a in [i,res[i]], the arc connecting border[i] and

//    border[a] will be a possible one.

inline std::unique_ptr<int[]> calculateForwardArcs(RawBorder &border,</int[]>

                                                   bool ambiguitiesCheck) {

  int const n = (int)border.size();

  std::unique_ptr<int[]> nextCorners;</int[]>

  std::unique_ptr<int[]> k = furthestKs(border, nextCorners);</int[]>

  std::unique_ptr<int[]> K(new int[n]);</int[]>

  std::unique_ptr<int[]> res(new int[n]);</int[]>

  // find K[i]= min {k[j]}, j=i..n-1.

  for (int i = 0; i < n; ++i) {

    int j;

    for (j = i, K[i] = k[i]; isCircular(i, j, K[i]); j = (j + 1) % n)

      if (isCircular(j, k[j], K[i])) K[i] = k[j];

  }

  // Finally, we perform the following clean-up operations:

  //  first, extremities of [i,K[i]] are clipped away, to obtain a

  //    smoother optimal polygon (and deal with cases like the unitary

  //    square);

  //  second, arcs of the kind [i,j] with j

  for (int i = n - 1, j = 0; j < n; i = j, ++j) {

    res[j] = K[i] < j ? (K[i] == 0 ? n - 1 : n) : K[i] - 1;

  }

  // Amibiguities check for vertex and edge superpositions. Prevent problems in

  // the forecoming

  // straight-skeleton thinning process.

  if (ambiguitiesCheck) {

    for (int i = 1; nextCorners[i] > 0; i = nextCorners[i]) {

      if (border[i].getAmbiguous() == RawBorderPoint::right) {

        // Check vertices from i (excluded) to res[res[i]]; if in it there

        // exists vertex k so that pos(k)==pos(i)...

        // This prevents the existence of 0 degree angles in the optimal

        // polygon.

        int rrPlus1 = (res[res[i] % n] + 1) % n;

        for (int j = nextCorners[i];

             isCircular(i, j, rrPlus1) &&

             j != i;  // remember that isCircular(a,a,b) == 1 ...

             j = nextCorners[j]) {

          if (border[j].getAmbiguous() &&

              (border[j].pos() == border[i].pos())) {

            res[res[i] % n] = j - 1;

            assert((res[i] % n) != j - 1);

            // Further, ensure res is increasing

            for (int k = res[i] % n; res[k] >= j - 1 && k >= 0; --k) {

              res[k] = j - 1;

              assert(k != j - 1);

            }

            break;

          }

        }

      }

    }

  }

  return res;

}

//--------------------------------------------------------------------------

// Let sum[i] and sum2[i] be respectively the sums of vertex coordinates

// from 0 to i, and the sums of their squares; sumsMix contain sums of

// xy terms.

inline void calculateSums(RawBorder &path) {

  unsigned int i, n = path.size();

  TPointD currentRelativePos;

  path.sums()    = new TPointD[n + 1];

  path.sums2()   = new TPointD[n + 1];

  path.sumsMix() = new double[n + 1];

  path.sums()[0].x = path.sums()[0].y = path.sums2()[0].x = path.sums2()[0].y =

      0;

  for (i = 1; i < path.size(); ++i) {

    currentRelativePos = convert(path[i].pos() - path[0].pos());

    path.sums()[i] = path.sums()[i - 1] + currentRelativePos;

    path.sums2()[i].x =

        path.sums2()[i - 1].x + currentRelativePos.x * currentRelativePos.x;

    path.sums2()[i].y =

        path.sums2()[i - 1].y + currentRelativePos.y * currentRelativePos.y;

    path.sumsMix()[i] =

        path.sumsMix()[i - 1] + currentRelativePos.x * currentRelativePos.y;

  }

  // path[n] is virtually intended as path[0], but we prefer to introduce

  // it in the optimality algorithm's count

  path.sums()[n].x = path.sums()[n].y = path.sums2()[n].x = path.sums2()[n].y =

      0;

}

//--------------------------------------------------------------------------

// Let a,b the index-extremities of an arc of this path.

// Then return its penalty.

inline double penalty(RawBorder &path, int a, int b) {

  int n = b - a + 1;

  TPointD v =

      convert(rotate90(path[b == path.size() ? 0 : b].pos() - path[a].pos()));

  TPointD sum   = path.sums()[b] - path.sums()[a];

  TPointD sum2  = path.sums2()[b] - path.sums2()[a];

  double sumMix = path.sumsMix()[b] - path.sumsMix()[a];

  double F1 = sum2.x - 2 * sum.x * path[a].x() + n * path[a].x() * path[a].x();

  double F2 = sum2.y - 2 * sum.y * path[a].y() + n * path[a].y() * path[a].y();

  double F3 = sumMix - sum.x * path[a].y() - sum.y * path[a].x() +

              n * path[a].x() * path[a].y();

  return sqrt((v.y * v.y * F1 + v.x * v.x * F2 - 2 * v.x * v.y * F3) / n);

}

//--------------------------------------------------------------------------

// NOTA: Il seguente algoritmo di riduzione assicura la semplicita' (debole) dei

// poligoni prodotti.

//

inline void reduceBorder(RawBorder &border, Contour &res,

                         bool ambiguitiesCheck) {

  int n = border.size();

  int minPenaltyNext;

  std::unique_ptr<int[]> minPenaltyNextArray(new int[n]);</int[]>

  // Calculate preliminary infos

  std::unique_ptr<int[]> longestArcFrom =</int[]>

      calculateForwardArcs(border, ambiguitiesCheck);

  calculateSums(border);

  std::unique_ptr<double[]> penaltyToEnd(new double[n + 1]);</double[]>

  // EXPLANATION:

  // The fastest way to extract the optimal reduced border is based on the

  // weakly monotonic property of longestArc[].

  // The minimal number of its vertices 'm' is easily found by

  // traversing the path with the longest step allowed. Let b[] be that

  // succession; then, given res[i], it has to be reached by a vertex in

  // the interval: {a[i-1], .. , b[i-1]}, where longestArc[a[i-1]]=a[i],

  // longestArc[a[i-1]-1]

  // Calculate m

  int m = 0;

  for (int i = 0; i < n; i = longestArcFrom[i]) ++m;

  // Calculate b[]

  std::unique_ptr<int[]> b(new int[m + 1]);</int[]>

  b[m] = n;

  for (int i = 0, j = 0; j < m; i = longestArcFrom[i], ++j) b[j] = i;

  // NOTE: a[] need not be completely found - we just remember the

  // a=a[j+1] currently needed.

  // Now, build the optimal polygon

  for (int j = m - 1, a = n; j >= 0; --j) {

    int k;

    for (k = b[j]; k >= 0 && longestArcFrom[k] >= a; --k) {

      penaltyToEnd[k] = infinity;

      for (int i = a; i <= longestArcFrom[k]; ++i) {

        double newPenalty = penaltyToEnd[i] + penalty(border, k, i);

        if (newPenalty < penaltyToEnd[k]) penaltyToEnd[k] = newPenalty;

        minPenaltyNext                                    = i;

      }

      minPenaltyNextArray[k] = minPenaltyNext;

    }

    a = k + 1;

  }

  // Finally, read off the optimal polygon

  res.resize(m);

  for (int i = 0, j = 0; i < n; i = minPenaltyNextArray[i], ++j) {

    res[j] = ContourNode(border[i].x(), border[i].y());

    // Ambiguities are still remembered in the output polygon.

    if (border[i].getAmbiguous() == RawBorderPoint::left)

      res[j].setAttribute(ContourNode::AMBIGUOUS_LEFT);

    if (border[i].getAmbiguous() == RawBorderPoint::right)

      res[j].setAttribute(ContourNode::AMBIGUOUS_RIGHT);

  }

  delete[] border.sums();

  delete[] border.sums2();

  delete[] border.sumsMix();

}

//--------------------------------------------------------------------------

// Reduction caller and list copier.

inline void reduceBorders(BorderList &borders, Contours &result,

                          bool ambiguitiesCheck) {

  unsigned int i, j;

  // Initialize output container

  result.resize(borders.size());

  // Copy results

  for (i = 0; i < borders.size(); ++i) {

    result[i].resize(borders[i].size());

    for (j = 0; j < borders[i].size(); ++j) {

      reduceBorder(*borders[i][j], result[i][j], ambiguitiesCheck);

      delete borders[i][j];

    }

  }

}

//--------------------------------------------------------------------------

//===========================

//    Polygonization Main

//===========================

// Extracts a polygonal, minimal yet faithful representation of image contours

// Contours* polygonize(const TRasterP &ras){

void polygonize(const TRasterP &ras, Contours &polygons,

                VectorizerCoreGlobals &g) {

  BorderList *borders;

  borders = extractBorders(ras, g.currConfig->m_threshold,

                           g.currConfig->m_despeckling);

  reduceBorders(*borders, polygons, g.currConfig->m_maxThickness > 0.0);

}