tesseract::C_OUTLINE Class Reference

#include <coutln.h>

Inheritance diagram for tesseract::C_OUTLINE:

Public Member Functions
	C_OUTLINE ()
	~C_OUTLINE ()
bool	flag (C_OUTLINE_FLAGS mask) const
void	set_flag (C_OUTLINE_FLAGS mask, bool value)
C_OUTLINE_LIST *	child ()
const TBOX &	bounding_box () const
void	set_step (int16_t stepindex, int8_t stepdir)
void	set_step (int16_t stepindex, DIR128 stepdir)
int32_t	pathlength () const
DIR128	step_dir (int index) const
ICOORD	step (int index) const
const ICOORD &	start_pos () const
ICOORD	position_at_index (int index) const
FCOORD	sub_pixel_pos_at_index (const ICOORD &pos, int index) const
int	direction_at_index (int index) const
int	edge_strength_at_index (int index) const
int	chain_code (int index) const
bool	operator> (C_OUTLINE &other) const
C_OUTLINE::area
Compute the area of the outline.
int32_t	area () const
C_OUTLINE::perimeter
Compute the perimeter of the outline and its first level children.
int32_t	perimeter () const
C_OUTLINE::outer_area
Compute the area of the outline.
int32_t	outer_area () const
C_OUTLINE::count_transitions
Compute the number of x and y maxes and mins in the outline. Parameters threshold winding number on size
int32_t	count_transitions (int32_t threshold)
C_OUTLINE::operator<
Returns true if the left operand is inside the right one. Parameters other other outline
bool	operator< (const C_OUTLINE &other) const
C_OUTLINE::winding_number
Returns the winding number of the outline around the given point. Parameters point point to wind around
int16_t	winding_number (ICOORD testpt) const
int16_t	turn_direction () const
C_OUTLINE::reverse
Reverse the direction of an outline.
void	reverse ()
C_OUTLINE::move
Move C_OUTLINE by vector Parameters vec vector to reposition OUTLINE by
void	move (const ICOORD vec)
bool	IsLegallyNested () const
void	RemoveSmallRecursive (int min_size, C_OUTLINE_IT *it)
void	ComputeEdgeOffsets (int threshold, Image pix)
void	ComputeBinaryOffsets ()
void	render (int left, int top, Image pix) const
void	render_outline (int left, int top, Image pix) const
C_OUTLINE::plot
Draw the outline in the given colour. Parameters window window to draw in colour colour to draw in
void	plot (ScrollView *window, ScrollView::Color colour) const
void	plot_normed (const DENORM &denorm, ScrollView::Color colour, ScrollView *window) const
Public Member Functions inherited from tesseract::ELIST_LINK
	ELIST_LINK ()
	ELIST_LINK (const ELIST_LINK &)
void	operator= (const ELIST_LINK &)

Static Public Member Functions
static C_OUTLINE *	deep_copy (const C_OUTLINE *src)

Static Public Attributes
static const int	kMaxOutlineLength = 16000

C_OUTLINE::C_OUTLINE
Constructor to build a C_OUTLINE from a rotation of a C_OUTLINE. Parameters srcline outline to rotate rotation rotate to coord
	C_OUTLINE (CRACKEDGE *startpt, ICOORD bot_left, ICOORD top_right, int16_t length)
	C_OUTLINE (ICOORD startpt, DIR128 *new_steps, int16_t length)
	C_OUTLINE (C_OUTLINE *srcline, FCOORD rotation)
static void	FakeOutline (const TBOX &box, C_OUTLINE_LIST *outlines)

C_OUTLINE::operator=
Assignment - deep copy data Parameters source assign from this
C_OUTLINE &	operator= (const C_OUTLINE &source)
static ICOORD	chain_step (int chaindir)

Detailed Description

Definition at line 75 of file coutln.h.

Constructor & Destructor Documentation

C_OUTLINE() [1/4]

tesseract::C_OUTLINE::C_OUTLINE ( )

inline

Definition at line 77 of file coutln.h.

              {
    stepcount = 0;
    offsets = nullptr;
  }

C_OUTLINE() [2/4]

tesseract::C_OUTLINE::C_OUTLINE	(	CRACKEDGE *	startpt,
		ICOORD	bot_left,
		ICOORD	top_right,
		int16_t	length
	)

Definition at line 57 of file coutln.cpp.

    : box(bot_left, top_right), start(startpt->pos), offsets(nullptr) {
  int16_t stepindex; // index to step
  CRACKEDGE *edgept; // current point
 
  stepcount = length; // no of steps
  if (length == 0) {
    return;
  }
  // get memory
  steps.resize(step_mem());
  edgept = startpt;
 
  for (stepindex = 0; stepindex < length; stepindex++) {
    // set compact step
    set_step(stepindex, edgept->stepdir);
    edgept = edgept->next;
  }
}

C_OUTLINE() [3/4]

tesseract::C_OUTLINE::C_OUTLINE	(	ICOORD	startpt,
		DIR128 *	new_steps,
		int16_t	length
	)

Definition at line 82 of file coutln.cpp.

    : start(startpt), offsets(nullptr) {
  int8_t dirdiff;    // direction difference
  DIR128 prevdir;    // previous direction
  DIR128 dir;        // current direction
  DIR128 lastdir;    // dir of last step
  TBOX new_box;      // easy bounding
  int16_t stepindex; // index to step
  int16_t srcindex;  // source steps
  ICOORD pos;        // current position
 
  pos = startpt;
  stepcount = length; // No. of steps.
  ASSERT_HOST(length >= 0);
  steps.resize(step_mem()); // Get memory.
 
  lastdir = new_steps[length - 1];
  prevdir = lastdir;
  for (stepindex = 0, srcindex = 0; srcindex < length; stepindex++, srcindex++) {
    new_box = TBOX(pos, pos);
    box += new_box;
    // copy steps
    dir = new_steps[srcindex];
    set_step(stepindex, dir);
    dirdiff = dir - prevdir;
    pos += step(stepindex);
    if ((dirdiff == 64 || dirdiff == -64) && stepindex > 0) {
      stepindex -= 2; // cancel there-and-back
      prevdir = stepindex >= 0 ? step_dir(stepindex) : lastdir;
    } else {
      prevdir = dir;
    }
  }
  ASSERT_HOST(pos.x() == startpt.x() && pos.y() == startpt.y());
  do {
    dirdiff = step_dir(stepindex - 1) - step_dir(0);
    if (dirdiff == 64 || dirdiff == -64) {
      start += step(0);
      stepindex -= 2; // cancel there-and-back
      for (int i = 0; i < stepindex; ++i) {
        set_step(i, step_dir(i + 1));
      }
    }
  } while (stepindex > 1 && (dirdiff == 64 || dirdiff == -64));
  stepcount = stepindex;
  ASSERT_HOST(stepcount >= 4);
}

C_OUTLINE() [4/4]

tesseract::C_OUTLINE::C_OUTLINE	(	C_OUTLINE *	srcline,
		FCOORD	rotation
	)

Definition at line 143 of file coutln.cpp.

                                                        : offsets(nullptr) {
  TBOX new_box;      // easy bounding
  int16_t stepindex; // index to step
  int16_t dirdiff;   // direction change
  ICOORD pos;        // current position
  ICOORD prevpos;    // previous dest point
 
  ICOORD destpos;                // destination point
  int16_t destindex = INT16_MAX; // index to step
  DIR128 dir;                    // coded direction
  uint8_t new_step;
 
  stepcount = srcline->stepcount * 2;
  if (stepcount == 0) {
    box = srcline->box;
    box.rotate(rotation);
    return;
  }
  // get memory
  steps.resize(step_mem());
 
  for (int iteration = 0; iteration < 2; ++iteration) {
    DIR128 round1 = iteration == 0 ? 32 : 0;
    DIR128 round2 = iteration != 0 ? 32 : 0;
    pos = srcline->start;
    prevpos = pos;
    prevpos.rotate(rotation);
    start = prevpos;
    box = TBOX(start, start);
    destindex = 0;
    for (stepindex = 0; stepindex < srcline->stepcount; stepindex++) {
      pos += srcline->step(stepindex);
      destpos = pos;
      destpos.rotate(rotation);
      //  tprintf("%i %i %i %i ", destpos.x(), destpos.y(), pos.x(), pos.y());
      while (destpos.x() != prevpos.x() || destpos.y() != prevpos.y()) {
        dir = DIR128(FCOORD(destpos - prevpos));
        dir += 64; // turn to step style
        new_step = dir.get_dir();
        //  tprintf(" %i\n", new_step);
        if (new_step & 31) {
          set_step(destindex++, dir + round1);
          prevpos += step(destindex - 1);
          if (destindex < 2 ||
              ((dirdiff = step_dir(destindex - 1) - step_dir(destindex - 2)) != -64 &&
               dirdiff != 64)) {
            set_step(destindex++, dir + round2);
            prevpos += step(destindex - 1);
          } else {
            prevpos -= step(destindex - 1);
            destindex--;
            prevpos -= step(destindex - 1);
            set_step(destindex - 1, dir + round2);
            prevpos += step(destindex - 1);
          }
        } else {
          set_step(destindex++, dir);
          prevpos += step(destindex - 1);
        }
        while (destindex >= 2 &&
               ((dirdiff = step_dir(destindex - 1) - step_dir(destindex - 2)) == -64 ||
                dirdiff == 64)) {
          prevpos -= step(destindex - 1);
          prevpos -= step(destindex - 2);
          destindex -= 2; // Forget u turn
        }
        // ASSERT_HOST(prevpos.x() == destpos.x() && prevpos.y() ==
        // destpos.y());
        new_box = TBOX(destpos, destpos);
        box += new_box;
      }
    }
    ASSERT_HOST(destpos.x() == start.x() && destpos.y() == start.y());
    while (destindex > 1) {
      dirdiff = step_dir(destindex - 1) - step_dir(0);
      if (dirdiff != 64 && dirdiff != -64) {
        break;
      }
      start += step(0);
      destindex -= 2;
      for (int i = 0; i < destindex; ++i) {
        set_step(i, step_dir(i + 1));
      }
    }
    if (destindex >= 4) {
      break;
    }
  }
  ASSERT_HOST(destindex <= stepcount);
  stepcount = destindex;
  destpos = start;
  for (stepindex = 0; stepindex < stepcount; stepindex++) {
    destpos += step(stepindex);
  }
  ASSERT_HOST(destpos.x() == start.x() && destpos.y() == start.y());
}

~C_OUTLINE()

tesseract::C_OUTLINE::~C_OUTLINE ( )

inline

Definition at line 94 of file coutln.h.

               { // destructor
    delete[] offsets;
  }

Member Function Documentation

area()

int32_t tesseract::C_OUTLINE::area

(

)

const

Definition at line 257 of file coutln.cpp.

                              {
  int stepindex;       // current step
  int32_t total_steps; // steps to do
  int32_t total;       // total area
  ICOORD pos;          // position of point
  ICOORD next_step;    // step to next pix
  // We aren't going to modify the list, or its contents, but there is
  // no const iterator.
  C_OUTLINE_IT it(const_cast<C_OUTLINE_LIST *>(&children));
 
  pos = start_pos();
  total_steps = pathlength();
  total = 0;
  for (stepindex = 0; stepindex < total_steps; stepindex++) {
    // all intersected
    next_step = step(stepindex);
    if (next_step.x() < 0) {
      total += pos.y();
    } else if (next_step.x() > 0) {
      total -= pos.y();
    }
    pos += next_step;
  }
  for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
    total += it.data()->area(); // add areas of children
  }
 
  return total;
}

bounding_box()

const TBOX & tesseract::C_OUTLINE::bounding_box ( ) const

inline

Definition at line 113 of file coutln.h.

                                   {
    return box;
  }

chain_code()

int tesseract::C_OUTLINE::chain_code ( int  index ) const

inline

Definition at line 197 of file coutln.h.

                                  { // index of step
    return (steps[index / 4] >> (index % 4 * 2)) & STEP_MASK;
  }

chain_step()

ICOORD tesseract::C_OUTLINE::chain_step ( int  chaindir )

static

Definition at line 1058 of file coutln.cpp.

                                         {
  return step_coords[chaindir % 4];
}

child()

C_OUTLINE_LIST * tesseract::C_OUTLINE::child ( )

inline

Definition at line 108 of file coutln.h.

                          { // get child list
    return &children;
  }

ComputeBinaryOffsets()

void tesseract::C_OUTLINE::ComputeBinaryOffsets

(

)

Adds sub-pixel resolution EdgeOffsets for the outline using only a binary image source.

Runs a sliding window of 5 edge steps over the outline, maintaining a count of the number of steps in each of the 4 directions in the window, and a sum of the x or y position of each step (as appropriate to its direction.) Ignores single-count steps EXCEPT the sharp U-turn and smoothes out the perpendicular direction. Eg

* ___              ___       Chain code from the left:
*    |___    ___   ___|      222122212223221232223000
*        |___|  |_|          Corresponding counts of each direction:
*                          0   00000000000000000123
*                          1   11121111001111100000
*                          2   44434443443333343321
*                          3   00000001111111112111
* Count of direction at center 41434143413313143313
* Step gets used?              YNYYYNYYYNYYNYNYYYyY (y= U-turn exception)
* Path redrawn showing only the used points:
* ___              ___
*     ___    ___   ___|
*         ___    _
* 

Sub-pixel edge position cannot be shown well with ASCII-art, but each horizontal step's y position is the mean of the y positions of the steps in the same direction in the sliding window, which makes a much smoother outline, without losing important detail.

Definition at line 850 of file coutln.cpp.

                                     {
  delete[] offsets;
  offsets = new EdgeOffset[stepcount];
  // Count of the number of steps in each direction in the sliding window.
  int dir_counts[4];
  // Sum of the positions (y for a horizontal step, x for vertical) in each
  // direction in the sliding window.
  int pos_totals[4];
  memset(dir_counts, 0, sizeof(dir_counts));
  memset(pos_totals, 0, sizeof(pos_totals));
  ICOORD pos = start;
  ICOORD tail_pos = pos;
  // tail_pos is the trailing position, with the next point to be lost from
  // the window.
  tail_pos -= step(stepcount - 1);
  tail_pos -= step(stepcount - 2);
  // head_pos is the leading position, with the next point to be added to the
  // window.
  ICOORD head_pos = tail_pos;
  // Set up the initial window with 4 points in [-2, 2)
  for (int s = -2; s < 2; ++s) {
    increment_step(s, 1, &head_pos, dir_counts, pos_totals);
  }
  for (int s = 0; s < stepcount; pos += step(s++)) {
    // At step s, s in the middle of [s-2, s+2].
    increment_step(s + 2, 1, &head_pos, dir_counts, pos_totals);
    int dir_index = chain_code(s);
    ICOORD step_vec = step(s);
    int best_diff = 0;
    int offset = 0;
    // Use only steps that have a count of >=2 OR the strong U-turn with a
    // single d and 2 at d-1 and 2 at d+1 (mod 4).
    if (dir_counts[dir_index] >= 2 ||
        (dir_counts[dir_index] == 1 && dir_counts[Modulo(dir_index - 1, 4)] == 2 &&
         dir_counts[Modulo(dir_index + 1, 4)] == 2)) {
      // Valid step direction.
      best_diff = dir_counts[dir_index];
      int edge_pos = step_vec.x() == 0 ? pos.x() : pos.y();
      // The offset proposes that the actual step should be positioned at
      // the mean position of the steps in the window of the same direction.
      // See ASCII art above.
      offset = pos_totals[dir_index] - best_diff * edge_pos;
    }
    offsets[s].offset_numerator = ClipToRange<int>(offset, -INT8_MAX, INT8_MAX);
    offsets[s].pixel_diff = ClipToRange<int>(best_diff, 0, UINT8_MAX);
    // The direction is just the vector from start to end of the window.
    FCOORD direction(head_pos.x() - tail_pos.x(), head_pos.y() - tail_pos.y());
    offsets[s].direction = direction.to_direction();
    increment_step(s - 2, -1, &tail_pos, dir_counts, pos_totals);
  }
}

ComputeEdgeOffsets()

void tesseract::C_OUTLINE::ComputeEdgeOffsets	(	int	threshold,
		Image	pix
	)

Adds sub-pixel resolution EdgeOffsets for the outline if the supplied pix is 8-bit. Does nothing otherwise. Operation: Consider the following near-horizontal line:

*   _________
*            |________
*                     |________
* 

At every position along this line, the gradient direction will be close to vertical. Extrapoaltion/interpolation of the position of the threshold that was used to binarize the image gives a more precise vertical position for each horizontal step, and the conflict in step direction and gradient direction can be used to ignore the vertical steps.

Definition at line 738 of file coutln.cpp.

                                                           {
  if (pixGetDepth(pix) != 8) {
    return;
  }
  const l_uint32 *data = pixGetData(pix);
  int wpl = pixGetWpl(pix);
  int width = pixGetWidth(pix);
  int height = pixGetHeight(pix);
  bool negative = flag(COUT_INVERSE);
  delete[] offsets;
  offsets = new EdgeOffset[stepcount];
  ICOORD pos = start;
  ICOORD prev_gradient;
  ComputeGradient(data, wpl, pos.x(), height - pos.y(), width, height, &prev_gradient);
  for (int s = 0; s < stepcount; ++s) {
    ICOORD step_vec = step(s);
    TPOINT pt1(pos);
    pos += step_vec;
    TPOINT pt2(pos);
    ICOORD next_gradient;
    ComputeGradient(data, wpl, pos.x(), height - pos.y(), width, height, &next_gradient);
    // Use the sum of the prev and next as the working gradient.
    ICOORD gradient = prev_gradient + next_gradient;
    // best_diff will be manipulated to be always positive.
    int best_diff = 0;
    // offset will be the extrapolation of the location of the greyscale
    // threshold from the edge with the largest difference, relative to the
    // location of the binary edge.
    int offset = 0;
    if (pt1.y == pt2.y && abs(gradient.y()) * 2 >= abs(gradient.x())) {
      // Horizontal step. diff_sign == 1 indicates black above.
      int diff_sign = (pt1.x > pt2.x) == negative ? 1 : -1;
      int x = std::min(pt1.x, pt2.x);
      int y = height - pt1.y;
      int best_sum = 0;
      int best_y = y;
      EvaluateVerticalDiff(data, wpl, diff_sign, x, y, height, &best_diff, &best_sum, &best_y);
      // Find the strongest edge.
      int test_y = y;
      do {
        ++test_y;
      } while (EvaluateVerticalDiff(data, wpl, diff_sign, x, test_y, height, &best_diff, &best_sum,
                                    &best_y));
      test_y = y;
      do {
        --test_y;
      } while (EvaluateVerticalDiff(data, wpl, diff_sign, x, test_y, height, &best_diff, &best_sum,
                                    &best_y));
      offset = diff_sign * (best_sum / 2 - threshold) + (y - best_y) * best_diff;
    } else if (pt1.x == pt2.x && abs(gradient.x()) * 2 >= abs(gradient.y())) {
      // Vertical step. diff_sign == 1 indicates black on the left.
      int diff_sign = (pt1.y > pt2.y) == negative ? 1 : -1;
      int x = pt1.x;
      int y = height - std::max(pt1.y, pt2.y);
      const l_uint32 *line = pixGetData(pix) + y * wpl;
      int best_sum = 0;
      int best_x = x;
      EvaluateHorizontalDiff(line, diff_sign, x, width, &best_diff, &best_sum, &best_x);
      // Find the strongest edge.
      int test_x = x;
      do {
        ++test_x;
      } while (
          EvaluateHorizontalDiff(line, diff_sign, test_x, width, &best_diff, &best_sum, &best_x));
      test_x = x;
      do {
        --test_x;
      } while (
          EvaluateHorizontalDiff(line, diff_sign, test_x, width, &best_diff, &best_sum, &best_x));
      offset = diff_sign * (threshold - best_sum / 2) + (best_x - x) * best_diff;
    }
    offsets[s].offset_numerator = ClipToRange<int>(offset, -INT8_MAX, INT8_MAX);
    offsets[s].pixel_diff = ClipToRange<int>(best_diff, 0, UINT8_MAX);
    if (negative) {
      gradient = -gradient;
    }
    // Compute gradient angle quantized to 256 directions, rotated by 64 (pi/2)
    // to convert from gradient direction to edge direction.
    offsets[s].direction = Modulo(FCOORD::binary_angle_plus_pi(gradient.angle()) + 64, 256);
    prev_gradient = next_gradient;
  }
}

count_transitions()

int32_t tesseract::C_OUTLINE::count_transitions

(

int32_t

threshold

)

Definition at line 347 of file coutln.cpp.

                                                      {
  bool first_was_max_x; // what was first
  bool first_was_max_y;
  bool looking_for_max_x; // what is next
  bool looking_for_min_x;
  bool looking_for_max_y; // what is next
  bool looking_for_min_y;
  int stepindex;       // current step
  int32_t total_steps; // steps to do
                       // current limits
  int32_t max_x, min_x, max_y, min_y;
  int32_t initial_x, initial_y; // initial limits
  int32_t total;                // total changes
  ICOORD pos;                   // position of point
  ICOORD next_step;             // step to next pix
 
  pos = start_pos();
  total_steps = pathlength();
  total = 0;
  max_x = min_x = pos.x();
  max_y = min_y = pos.y();
  looking_for_max_x = true;
  looking_for_min_x = true;
  looking_for_max_y = true;
  looking_for_min_y = true;
  first_was_max_x = false;
  first_was_max_y = false;
  initial_x = pos.x();
  initial_y = pos.y(); // stop uninit warning
  for (stepindex = 0; stepindex < total_steps; stepindex++) {
    // all intersected
    next_step = step(stepindex);
    pos += next_step;
    if (next_step.x() < 0) {
      if (looking_for_max_x && pos.x() < min_x) {
        min_x = pos.x();
      }
      if (looking_for_min_x && max_x - pos.x() > threshold) {
        if (looking_for_max_x) {
          initial_x = max_x;
          first_was_max_x = false;
        }
        total++;
        looking_for_max_x = true;
        looking_for_min_x = false;
        min_x = pos.x(); // reset min
      }
    } else if (next_step.x() > 0) {
      if (looking_for_min_x && pos.x() > max_x) {
        max_x = pos.x();
      }
      if (looking_for_max_x && pos.x() - min_x > threshold) {
        if (looking_for_min_x) {
          initial_x = min_x; // remember first min
          first_was_max_x = true;
        }
        total++;
        looking_for_max_x = false;
        looking_for_min_x = true;
        max_x = pos.x();
      }
    } else if (next_step.y() < 0) {
      if (looking_for_max_y && pos.y() < min_y) {
        min_y = pos.y();
      }
      if (looking_for_min_y && max_y - pos.y() > threshold) {
        if (looking_for_max_y) {
          initial_y = max_y; // remember first max
          first_was_max_y = false;
        }
        total++;
        looking_for_max_y = true;
        looking_for_min_y = false;
        min_y = pos.y(); // reset min
      }
    } else {
      if (looking_for_min_y && pos.y() > max_y) {
        max_y = pos.y();
      }
      if (looking_for_max_y && pos.y() - min_y > threshold) {
        if (looking_for_min_y) {
          initial_y = min_y; // remember first min
          first_was_max_y = true;
        }
        total++;
        looking_for_max_y = false;
        looking_for_min_y = true;
        max_y = pos.y();
      }
    }
  }
  if (first_was_max_x && looking_for_min_x) {
    if (max_x - initial_x > threshold) {
      total++;
    } else {
      total--;
    }
  } else if (!first_was_max_x && looking_for_max_x) {
    if (initial_x - min_x > threshold) {
      total++;
    } else {
      total--;
    }
  }
  if (first_was_max_y && looking_for_min_y) {
    if (max_y - initial_y > threshold) {
      total++;
    } else {
      total--;
    }
  } else if (!first_was_max_y && looking_for_max_y) {
    if (initial_y - min_y > threshold) {
      total++;
    } else {
      total--;
    }
  }
 
  return total;
}

deep_copy()

static C_OUTLINE * tesseract::C_OUTLINE::deep_copy ( const C_OUTLINE *  src )

inlinestatic

Definition at line 261 of file coutln.h.

                                                    {
    auto *outline = new C_OUTLINE;
    *outline = *src;
    return outline;
  }

direction_at_index()

int tesseract::C_OUTLINE::direction_at_index ( int  index ) const

inline

Definition at line 178 of file coutln.h.

                                          {
    if (offsets != nullptr && offsets[index].pixel_diff > 0) {
      return offsets[index].direction;
    }
    return -1;
  }

edge_strength_at_index()

int tesseract::C_OUTLINE::edge_strength_at_index ( int  index ) const

inline

Definition at line 188 of file coutln.h.

                                              {
    if (offsets != nullptr) {
      return offsets[index].pixel_diff;
    }
    return 1;
  }

FakeOutline()

void tesseract::C_OUTLINE::FakeOutline ( const TBOX &  box, C_OUTLINE_LIST *  outlines  )

static

Definition at line 241 of file coutln.cpp.

                                                                     {
  C_OUTLINE_IT ol_it(outlines);
  // Make a C_OUTLINE from the bounds. This is a bit of a hack,
  // as there is no outline, just a bounding box, but it works nicely.
  CRACKEDGE start;
  start.pos = box.topleft();
  auto *outline = new C_OUTLINE(&start, box.topleft(), box.botright(), 0);
  ol_it.add_to_end(outline);
}

flag()

bool tesseract::C_OUTLINE::flag ( C_OUTLINE_FLAGS  mask ) const

inline

Definition at line 98 of file coutln.h.

                                  { // flag to test
    return flags[mask];
  }

IsLegallyNested()

bool tesseract::C_OUTLINE::IsLegallyNested

(

)

const

Returns true if *this and its children are legally nested. The outer area of a child should have the opposite sign to the parent. If not, it means we have discarded an outline in between (probably due to excessive length).

Definition at line 620 of file coutln.cpp.

                                      {
  if (stepcount == 0) {
    return true;
  }
  int64_t parent_area = outer_area();
  // We aren't going to modify the list, or its contents, but there is
  // no const iterator.
  C_OUTLINE_IT child_it(const_cast<C_OUTLINE_LIST *>(&children));
  for (child_it.mark_cycle_pt(); !child_it.cycled_list(); child_it.forward()) {
    const C_OUTLINE *child = child_it.data();
    if (child->outer_area() * parent_area > 0 || !child->IsLegallyNested()) {
      return false;
    }
  }
  return true;
}

move()

void tesseract::C_OUTLINE::move

(

const ICOORD

vec

)

Definition at line 603 of file coutln.cpp.

                                     {
  C_OUTLINE_IT it(&children); // iterator
 
  box.move(vec);
  start += vec;
 
  for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
    it.data()->move(vec); // move child outlines
  }
}

operator<()

bool tesseract::C_OUTLINE::operator<

(

const C_OUTLINE &

other

)

const

Definition at line 475 of file coutln.cpp.

                                                      {
  int16_t count = 0; // winding count
  ICOORD pos;        // position of point
  int32_t stepindex; // index to cstep
 
  if (!box.overlap(other.box)) {
    return false; // can't be contained
  }
  if (stepcount == 0) {
    return other.box.contains(this->box);
  }
 
  pos = start;
  for (stepindex = 0; stepindex < stepcount && (count = other.winding_number(pos)) == INTERSECTING;
       stepindex++) {
    pos += step(stepindex); // try all points
  }
  if (count == INTERSECTING) {
    // all intersected
    pos = other.start;
    for (stepindex = 0;
         stepindex < other.stepcount && (count = winding_number(pos)) == INTERSECTING;
         stepindex++) {
      // try other way round
      pos += other.step(stepindex);
    }
    return count == INTERSECTING || count == 0;
  }
  return count != 0;
}

operator=()

C_OUTLINE & tesseract::C_OUTLINE::operator=

(

const C_OUTLINE &

source

)

Definition at line 1017 of file coutln.cpp.

                                                       {
  box = source.box;
  start = source.start;
  if (!children.empty()) {
    children.clear();
  }
  children.deep_copy(&source.children, &deep_copy);
  delete[] offsets;
  offsets = nullptr;
  stepcount = source.stepcount;
  if (stepcount > 0) {
    steps.resize(step_mem());
    memmove(&steps[0], &source.steps[0], step_mem());
    if (source.offsets != nullptr) {
      offsets = new EdgeOffset[stepcount];
      memcpy(offsets, source.offsets, stepcount * sizeof(*offsets));
    }
  }
  return *this;
}

operator>()

bool tesseract::C_OUTLINE::operator> ( C_OUTLINE &  other ) const

inline

Definition at line 209 of file coutln.h.

                              {
    return other < *this; // use the < to do it
  }

outer_area()

int32_t tesseract::C_OUTLINE::outer_area

(

)

const

Definition at line 313 of file coutln.cpp.

                                    {
  int stepindex;       // current step
  int32_t total_steps; // steps to do
  int32_t total;       // total area
  ICOORD pos;          // position of point
  ICOORD next_step;    // step to next pix
 
  pos = start_pos();
  total_steps = pathlength();
  if (total_steps == 0) {
    return box.area();
  }
  total = 0;
  for (stepindex = 0; stepindex < total_steps; stepindex++) {
    // all intersected
    next_step = step(stepindex);
    if (next_step.x() < 0) {
      total += pos.y();
    } else if (next_step.x() > 0) {
      total -= pos.y();
    }
    pos += next_step;
  }
 
  return total;
}

pathlength()

int32_t tesseract::C_OUTLINE::pathlength ( ) const

inline

Definition at line 134 of file coutln.h.

                             { // get path length
    return stepcount;
  }

perimeter()

int32_t tesseract::C_OUTLINE::perimeter

(

)

const

Definition at line 293 of file coutln.cpp.

                                   {
  int32_t total_steps; // Return value.
  // We aren't going to modify the list, or its contents, but there is
  // no const iterator.
  C_OUTLINE_IT it(const_cast<C_OUTLINE_LIST *>(&children));
 
  total_steps = pathlength();
  for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
    total_steps += it.data()->pathlength(); // Add perimeters of children.
  }
 
  return total_steps;
}

plot()

void tesseract::C_OUTLINE::plot	(	ScrollView *	window,
		ScrollView::Color	colour
	)		const

Definition at line 952 of file coutln.cpp.

                                                                     {
  int16_t stepindex; // index to cstep
  ICOORD pos;        // current position
  DIR128 stepdir;    // direction of step
 
  pos = start; // current position
  window->Pen(colour);
  if (stepcount == 0) {
    window->Rectangle(box.left(), box.top(), box.right(), box.bottom());
    return;
  }
  window->SetCursor(pos.x(), pos.y());
 
  stepindex = 0;
  while (stepindex < stepcount) {
    pos += step(stepindex); // step to next
    stepdir = step_dir(stepindex);
    stepindex++; // count steps
    // merge straight lines
    while (stepindex < stepcount && stepdir.get_dir() == step_dir(stepindex).get_dir()) {
      pos += step(stepindex);
      stepindex++;
    }
    window->DrawTo(pos.x(), pos.y());
  }
}

plot_normed()

void tesseract::C_OUTLINE::plot_normed	(	const DENORM &	denorm,
		ScrollView::Color	colour,
		ScrollView *	window
	)		const

Draws the outline in the given colour, normalized using the given denorm, making use of sub-pixel accurate information if available.

Definition at line 983 of file coutln.cpp.

                                                      {
  window->Pen(colour);
  if (stepcount == 0) {
    window->Rectangle(box.left(), box.top(), box.right(), box.bottom());
    return;
  }
  const DENORM *root_denorm = denorm.RootDenorm();
  ICOORD pos = start; // current position
  FCOORD f_pos = sub_pixel_pos_at_index(pos, 0);
  FCOORD pos_normed;
  denorm.NormTransform(root_denorm, f_pos, &pos_normed);
  window->SetCursor(IntCastRounded(pos_normed.x()), IntCastRounded(pos_normed.y()));
  for (int s = 0; s < stepcount; pos += step(s++)) {
    int edge_weight = edge_strength_at_index(s);
    if (edge_weight == 0) {
      // This point has conflicting gradient and step direction, so ignore it.
      continue;
    }
    FCOORD f_pos = sub_pixel_pos_at_index(pos, s);
    FCOORD pos_normed;
    denorm.NormTransform(root_denorm, f_pos, &pos_normed);
    window->DrawTo(IntCastRounded(pos_normed.x()), IntCastRounded(pos_normed.y()));
  }
}

position_at_index()

ICOORD tesseract::C_OUTLINE::position_at_index ( int  index ) const

inline

Definition at line 152 of file coutln.h.

                                            {
    ICOORD pos = start;
    for (int i = 0; i < index; ++i) {
      pos += step(i);
    }
    return pos;
  }

RemoveSmallRecursive()

void tesseract::C_OUTLINE::RemoveSmallRecursive	(	int	min_size,
		C_OUTLINE_IT *	it
	)

If this outline is smaller than the given min_size, delete this and remove from its list, via *it, after checking that *it points to this. Otherwise, if any children of this are too small, delete them. On entry, *it must be an iterator pointing to this. If this gets deleted then this is extracted from *it, so an iteration can continue.

Parameters

min_size	minimum size for outline
it	outline iterator

Definition at line 646 of file coutln.cpp.

                                                                   {
  if (box.width() < min_size || box.height() < min_size) {
    ASSERT_HOST(this == it->data());
    delete it->extract(); // Too small so get rid of it and any children.
  } else if (!children.empty()) {
    // Search the children of this, deleting any that are too small.
    C_OUTLINE_IT child_it(&children);
    for (child_it.mark_cycle_pt(); !child_it.cycled_list(); child_it.forward()) {
      C_OUTLINE *child = child_it.data();
      child->RemoveSmallRecursive(min_size, &child_it);
    }
  }
}

render()

void tesseract::C_OUTLINE::render	(	int	left,
		int	top,
		Image	pix
	)		const

Renders the outline to the given pix, with left and top being the coords of the upper-left corner of the pix.

Definition at line 906 of file coutln.cpp.

                                                         {
  ICOORD pos = start;
  for (int stepindex = 0; stepindex < stepcount; ++stepindex) {
    ICOORD next_step = step(stepindex);
    if (next_step.y() < 0) {
      pixRasterop(pix, 0, top - pos.y(), pos.x() - left, 1, PIX_NOT(PIX_DST), nullptr, 0, 0);
    } else if (next_step.y() > 0) {
      pixRasterop(pix, 0, top - pos.y() - 1, pos.x() - left, 1, PIX_NOT(PIX_DST), nullptr, 0, 0);
    }
    pos += next_step;
  }
}

render_outline()

void tesseract::C_OUTLINE::render_outline	(	int	left,
		int	top,
		Image	pix
	)		const

Renders just the outline to the given pix (no fill), with left and top being the coords of the upper-left corner of the pix.

Parameters

left	coord
top	coord
pix	the pix to outline

Definition at line 926 of file coutln.cpp.

                                                                 {
  ICOORD pos = start;
  for (int stepindex = 0; stepindex < stepcount; ++stepindex) {
    ICOORD next_step = step(stepindex);
    if (next_step.y() < 0) {
      pixSetPixel(pix, pos.x() - left, top - pos.y(), 1);
    } else if (next_step.y() > 0) {
      pixSetPixel(pix, pos.x() - left - 1, top - pos.y() - 1, 1);
    } else if (next_step.x() < 0) {
      pixSetPixel(pix, pos.x() - left - 1, top - pos.y(), 1);
    } else if (next_step.x() > 0) {
      pixSetPixel(pix, pos.x() - left, top - pos.y() - 1, 1);
    }
    pos += next_step;
  }
}

reverse()

void tesseract::C_OUTLINE::reverse

(

)

Definition at line 580 of file coutln.cpp.

                        {      // reverse drection
  DIR128 halfturn = MODULUS / 2; // amount to shift
  DIR128 stepdir;                // direction of step
  int16_t stepindex;             // index to cstep
  int16_t farindex;              // index to other side
  int16_t halfsteps;             // half of stepcount
 
  halfsteps = (stepcount + 1) / 2;
  for (stepindex = 0; stepindex < halfsteps; stepindex++) {
    farindex = stepcount - stepindex - 1;
    stepdir = step_dir(stepindex);
    set_step(stepindex, step_dir(farindex) + halfturn);
    set_step(farindex, stepdir + halfturn);
  }
}

set_flag()

void tesseract::C_OUTLINE::set_flag ( C_OUTLINE_FLAGS  mask, bool  value  )

inline

Definition at line 102 of file coutln.h.

                  {         // value to set
    flags.set(mask, value);
  }

set_step() [1/2]

void tesseract::C_OUTLINE::set_step ( int16_t  stepindex, DIR128  stepdir  )

inline

Definition at line 124 of file coutln.h.

                      {  // direction
    // clean it
    int8_t chaindir = stepdir.get_dir() >> (DIRBITS - 2);
    // difference
    set_step(stepindex, chaindir);
    // squeeze 4 into byte
  }

set_step() [2/2]

void tesseract::C_OUTLINE::set_step ( int16_t  stepindex, int8_t  stepdir  )

inline

Definition at line 116 of file coutln.h.

                      {  // chain code
    int shift = stepindex % 4 * 2;
    uint8_t mask = 3 << shift;
    steps[stepindex / 4] = ((stepdir << shift) & mask) | (steps[stepindex / 4] & ~mask);
    // squeeze 4 into byte
  }

start_pos()

const ICOORD & tesseract::C_OUTLINE::start_pos ( ) const

inline

Definition at line 147 of file coutln.h.

                                  {
    return start;
  }

step()

ICOORD tesseract::C_OUTLINE::step ( int  index ) const

inline

Definition at line 143 of file coutln.h.

                               { // index of step
    return step_coords[chain_code(index)];
  }

step_dir()

DIR128 tesseract::C_OUTLINE::step_dir ( int  index ) const

inline

Definition at line 138 of file coutln.h.

                                   {
    return DIR128(
        static_cast<int16_t>(((steps[index / 4] >> (index % 4 * 2)) & STEP_MASK) << (DIRBITS - 2)));
  }

sub_pixel_pos_at_index()

FCOORD tesseract::C_OUTLINE::sub_pixel_pos_at_index ( const ICOORD &  pos, int  index  ) const

inline

Definition at line 163 of file coutln.h.

                                                                    {
    const ICOORD &step_to_next(step(index));
    FCOORD f_pos(pos.x() + step_to_next.x() / 2.0f, pos.y() + step_to_next.y() / 2.0f);
    if (offsets != nullptr && offsets[index].pixel_diff > 0) {
      float offset = offsets[index].offset_numerator;
      offset /= offsets[index].pixel_diff;
      if (step_to_next.x() != 0) {
        f_pos.set_y(f_pos.y() + offset);
      } else {
        f_pos.set_x(f_pos.x() + offset);
      }
    }
    return f_pos;
  }

turn_direction()

int16_t tesseract::C_OUTLINE::turn_direction

(

)

const

C_OUTLINE::turn_direction

Returns

the sum direction delta of the outline.

Definition at line 551 of file coutln.cpp.

                                        { // winding number
  DIR128 prevdir;                           // previous direction
  DIR128 dir;                               // current direction
  int16_t stepindex;                        // index to cstep
  int8_t dirdiff;                           // direction difference
  int16_t count;                            // winding count
 
  if (stepcount == 0) {
    return 128;
  }
  count = 0;
  prevdir = step_dir(stepcount - 1);
  for (stepindex = 0; stepindex < stepcount; stepindex++) {
    dir = step_dir(stepindex);
    dirdiff = dir - prevdir;
    ASSERT_HOST(dirdiff == 0 || dirdiff == 32 || dirdiff == -32);
    count += dirdiff;
    prevdir = dir;
  }
  ASSERT_HOST(count == 128 || count == -128);
  return count; // winding number
}

winding_number()

int16_t tesseract::C_OUTLINE::winding_number

(

ICOORD

testpt

)

const

Definition at line 513 of file coutln.cpp.

                                                    {
  int16_t stepindex; // index to cstep
  int16_t count;     // winding count
  ICOORD vec;        // to current point
  ICOORD stepvec;    // step vector
  int32_t cross;     // cross product
 
  vec = start - point; // vector to it
  count = 0;
  for (stepindex = 0; stepindex < stepcount; stepindex++) {
    stepvec = step(stepindex); // get the step
                               // crossing the line
    if (vec.y() <= 0 && vec.y() + stepvec.y() > 0) {
      cross = vec * stepvec; // cross product
      if (cross > 0) {
        count++; // crossing right half
      } else if (cross == 0) {
        return INTERSECTING; // going through point
      }
    } else if (vec.y() > 0 && vec.y() + stepvec.y() <= 0) {
      cross = vec * stepvec;
      if (cross < 0) {
        count--; // crossing back
      } else if (cross == 0) {
        return INTERSECTING; // illegal
      }
    }
    vec += stepvec; // sum vectors
  }
  return count; // winding number
}

Member Data Documentation

kMaxOutlineLength

const int tesseract::C_OUTLINE::kMaxOutlineLength = 16000

static

Definition at line 273 of file coutln.h.

---

The documentation for this class was generated from the following files:

• /media/home/debian/src/github/tesseract-ocr/tesseract/src/ccstruct/coutln.h
• /media/home/debian/src/github/tesseract-ocr/tesseract/src/ccstruct/coutln.cpp