oldbasel.cpp

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/**********************************************************************
 * File:        oldbasel.cpp  (Formerly oldbl.c)
 * Description: A re-implementation of the old baseline algorithm.
 * Author:      Ray Smith
 *
 * (C) Copyright 1993, 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.
 *
 **********************************************************************/
 
#include <vector>       // for std::vector
#include "ccstruct.h"
#include "statistc.h"
#include "quadlsq.h"
#include "detlinefit.h"
#include "makerow.h"
#include "drawtord.h"
#include "oldbasel.h"
#include "textord.h"
#include "tprintf.h"
 
// Include automatically generated configuration file if running autoconf.
#ifdef HAVE_CONFIG_H
#include "config_auto.h"
#endif
 
#include <algorithm>
 
static BOOL_VAR (textord_really_old_xheight, false,
"Use original wiseowl xheight");
BOOL_VAR (textord_oldbl_debug, false, "Debug old baseline generation");
static BOOL_VAR (textord_debug_baselines, false, "Debug baseline generation");
static BOOL_VAR (textord_oldbl_paradef, true, "Use para default mechanism");
static BOOL_VAR (textord_oldbl_split_splines, true, "Split stepped splines");
static BOOL_VAR (textord_oldbl_merge_parts, true, "Merge suspect partitions");
static BOOL_VAR (oldbl_corrfix, true, "Improve correlation of heights");
static BOOL_VAR (oldbl_xhfix, false,
"Fix bug in modes threshold for xheights");
static BOOL_VAR(textord_ocropus_mode, false, "Make baselines for ocropus");
static double_VAR (oldbl_xhfract, 0.4, "Fraction of est allowed in calc");
static INT_VAR (oldbl_holed_losscount, 10,
"Max lost before fallback line used");
static double_VAR (oldbl_dot_error_size, 1.26, "Max aspect ratio of a dot");
static double_VAR (textord_oldbl_jumplimit, 0.15,
"X fraction for new partition");
 
#define TURNLIMIT          1     /*min size for turning point */
#define X_HEIGHT_FRACTION  0.7   /*x-height/caps height */
#define DESCENDER_FRACTION 0.5   /*descender/x-height */
#define MIN_ASC_FRACTION   0.20  /*min size of ascenders */
#define MIN_DESC_FRACTION  0.25  /*min size of descenders */
#define MINASCRISE         2.0   /*min ascender/desc step */
#define MAXHEIGHTVARIANCE  0.15  /*accepted variation in x-height */
#define MAXHEIGHT          300   /*max blob height */
#define MAXOVERLAP         0.1   /*max 10% missed overlap */
#define MAXBADRUN          2     /*max non best for failed */
#define HEIGHTBUCKETS      200   /* Num of buckets */
#define MODENUM            10
#define MAXPARTS      6
#define SPLINESIZE      23
 
#define ABS(x) ((x)<0 ? (-(x)) : (x))
 
namespace tesseract {
 
/**********************************************************************
 * make_old_baselines
 *
 * Top level function to make baselines the old way.
 **********************************************************************/
 
void Textord::make_old_baselines(TO_BLOCK* block,   // block to do
                                 bool testing_on,  // correct orientation
                                 float gradient) {
  QSPLINE *prev_baseline;        // baseline of previous row
  TO_ROW *row;                   // current row
  TO_ROW_IT row_it = block->get_rows();
  BLOBNBOX_IT blob_it;
 
  prev_baseline = nullptr;          // nothing yet
  for (row_it.mark_cycle_pt(); !row_it.cycled_list(); row_it.forward()) {
    row = row_it.data();
    find_textlines(block, row, 2, nullptr);
    if (row->xheight <= 0 && prev_baseline != nullptr)
      find_textlines(block, row, 2, prev_baseline);
    if (row->xheight > 0) {  // was a good one
      prev_baseline = &row->baseline;
    } else {
      prev_baseline = nullptr;
      blob_it.set_to_list(row->blob_list());
      if (textord_debug_baselines)
        tprintf("Row baseline generation failed on row at (%d,%d)\n",
          blob_it.data()->bounding_box().left(),
          blob_it.data()->bounding_box().bottom());
    }
  }
  correlate_lines(block, gradient);
  block->block->set_xheight(block->xheight);
}
 
 
/**********************************************************************
 * correlate_lines
 *
 * Correlate the x-heights and ascender heights of a block to fill-in
 * the ascender height and descender height for rows without one.
 * Also fix baselines of rows without a decent fit.
 **********************************************************************/
 
void Textord::correlate_lines(TO_BLOCK *block, float gradient) {
  int rowcount;                  /*no of rows to do */
  int rowindex;                  /*no of row */
                                 // iterator
  TO_ROW_IT row_it = block->get_rows ();
 
  rowcount = row_it.length ();
  if (rowcount == 0) {
                                 //default value
    block->xheight = block->line_size;
    return;                      /*none to do */
  }
  // array of ptrs
  std::vector <TO_ROW *> rows(rowcount);
  rowindex = 0;
  for (row_it.mark_cycle_pt (); !row_it.cycled_list (); row_it.forward ())
                                 //make array
    rows[rowindex++] = row_it.data ();
 
                                 /*try to fix bad lines */
  correlate_neighbours(block, &rows[0], rowcount);
 
  if (textord_really_old_xheight || textord_old_xheight) {
    block->xheight = static_cast<float>(correlate_with_stats(&rows[0], rowcount, block));
    if (block->xheight <= 0)
      block->xheight = block->line_size * tesseract::CCStruct::kXHeightFraction;
    if (block->xheight < textord_min_xheight)
      block->xheight = (float) textord_min_xheight;
  } else {
    compute_block_xheight(block, gradient);
  }
}
 
 
/**********************************************************************
 * correlate_neighbours
 *
 * Try to fix rows that had a bad spline fit by using neighbours.
 **********************************************************************/
 
void Textord::correlate_neighbours(TO_BLOCK *block,  // block rows are in.
                                   TO_ROW **rows,    // rows of block.
                                   int rowcount) {   // no of rows to do.
  TO_ROW *row;                   /*current row */
  int rowindex;                  /*no of row */
  int otherrow;                  /*second row */
  int upperrow;                  /*row above to use */
  int lowerrow;                  /*row below to use */
  float biggest;
 
  for (rowindex = 0; rowindex < rowcount; rowindex++) {
    row = rows[rowindex];        /*current row */
    if (row->xheight < 0) {
                                 /*quadratic failed */
      for (otherrow = rowindex - 2;
        otherrow >= 0
        && (rows[otherrow]->xheight < 0.0
        || !row->baseline.overlap (&rows[otherrow]->baseline,
        MAXOVERLAP)); otherrow--);
      upperrow = otherrow;       /*decent row above */
      for (otherrow = rowindex + 1;
        otherrow < rowcount
        && (rows[otherrow]->xheight < 0.0
        || !row->baseline.overlap (&rows[otherrow]->baseline,
        MAXOVERLAP)); otherrow++);
      lowerrow = otherrow;       /*decent row below */
      if (upperrow >= 0)
        find_textlines(block, row, 2, &rows[upperrow]->baseline);
      if (row->xheight < 0 && lowerrow < rowcount)
        find_textlines(block, row, 2, &rows[lowerrow]->baseline);
      if (row->xheight < 0) {
        if (upperrow >= 0)
          find_textlines(block, row, 1, &rows[upperrow]->baseline);
        else if (lowerrow < rowcount)
          find_textlines(block, row, 1, &rows[lowerrow]->baseline);
      }
    }
  }
 
  for (biggest = 0.0f, rowindex = 0; rowindex < rowcount; rowindex++) {
    row = rows[rowindex];        /*current row */
    if (row->xheight < 0)        /*linear failed */
                                 /*make do */
        row->xheight = -row->xheight;
    biggest = std::max(biggest, row->xheight);
  }
}
 
 
/**********************************************************************
 * correlate_with_stats
 *
 * correlate the x-heights and ascender heights of a block to fill-in
 * the ascender height and descender height for rows without one.
 **********************************************************************/
 
int Textord::correlate_with_stats(TO_ROW **rows,  // rows of block.
                                  int rowcount,   // no of rows to do.
                                  TO_BLOCK* block) {
  TO_ROW *row;                   /*current row */
  int rowindex;                  /*no of row */
  float lineheight;              /*mean x-height */
  float ascheight;               /*average ascenders */
  float minascheight;            /*min allowed ascheight */
  int xcount;                    /*no of samples for xheight */
  float fullheight;              /*mean top height */
  int fullcount;                 /*no of samples */
  float descheight;              /*mean descender drop */
  float mindescheight;           /*min allowed descheight */
  int desccount;                 /*no of samples */
 
                                 /*no samples */
  xcount = fullcount = desccount = 0;
  lineheight = ascheight = fullheight = descheight = 0.0;
  for (rowindex = 0; rowindex < rowcount; rowindex++) {
    row = rows[rowindex];        /*current row */
    if (row->ascrise > 0.0) {    /*got ascenders? */
      lineheight += row->xheight;/*average x-heights */
      ascheight += row->ascrise; /*average ascenders */
      xcount++;
    }
    else {
      fullheight += row->xheight;/*assume full height */
      fullcount++;
    }
    if (row->descdrop < 0.0) {   /*got descenders? */
                                 /*average descenders */
      descheight += row->descdrop;
      desccount++;
    }
  }
 
  if (xcount > 0 && (!oldbl_corrfix || xcount >= fullcount)) {
    lineheight /= xcount;        /*average x-height */
                                 /*average caps height */
    fullheight = lineheight + ascheight / xcount;
                                 /*must be decent size */
    if (fullheight < lineheight * (1 + MIN_ASC_FRACTION))
      fullheight = lineheight * (1 + MIN_ASC_FRACTION);
  }
  else {
    fullheight /= fullcount;     /*average max height */
                                 /*guess x-height */
    lineheight = fullheight * X_HEIGHT_FRACTION;
  }
  if (desccount > 0 && (!oldbl_corrfix || desccount >= rowcount / 2))
    descheight /= desccount;     /*average descenders */
  else
                                 /*guess descenders */
    descheight = -lineheight * DESCENDER_FRACTION;
 
  if (lineheight > 0.0f)
    block->block->set_cell_over_xheight((fullheight - descheight) / lineheight);
 
  minascheight = lineheight * MIN_ASC_FRACTION;
  mindescheight = -lineheight * MIN_DESC_FRACTION;
  for (rowindex = 0; rowindex < rowcount; rowindex++) {
    row = rows[rowindex];        /*do each row */
    row->all_caps = false;
    if (row->ascrise / row->xheight < MIN_ASC_FRACTION) {
    /*no ascenders */
      if (row->xheight >= lineheight * (1 - MAXHEIGHTVARIANCE)
      && row->xheight <= lineheight * (1 + MAXHEIGHTVARIANCE)) {
        row->ascrise = fullheight - lineheight;
                                 /*set to average */
        row->xheight = lineheight;
 
      }
      else if (row->xheight >= fullheight * (1 - MAXHEIGHTVARIANCE)
      && row->xheight <= fullheight * (1 + MAXHEIGHTVARIANCE)) {
        row->ascrise = row->xheight - lineheight;
                                 /*set to average */
        row->xheight = lineheight;
        row->all_caps = true;
      }
      else {
        row->ascrise = (fullheight - lineheight) * row->xheight
          / fullheight;
                                 /*scale it */
        row->xheight -= row->ascrise;
        row->all_caps = true;
      }
      if (row->ascrise < minascheight)
        row->ascrise =
          row->xheight * ((1.0 - X_HEIGHT_FRACTION) / X_HEIGHT_FRACTION);
    }
    if (row->descdrop > mindescheight) {
      if (row->xheight >= lineheight * (1 - MAXHEIGHTVARIANCE)
        && row->xheight <= lineheight * (1 + MAXHEIGHTVARIANCE))
                                 /*set to average */
          row->descdrop = descheight;
      else
        row->descdrop = -row->xheight * DESCENDER_FRACTION;
    }
  }
  return static_cast<int>(lineheight);       //block xheight
}
 
 
/**********************************************************************
 * find_textlines
 *
 * Compute the baseline for the given row.
 **********************************************************************/
 
void Textord::find_textlines(TO_BLOCK *block,  // block row is in
                             TO_ROW *row,      // row to do
                             int degree,       // required approximation
                             QSPLINE *spline) {  // starting spline
  int partcount;                 /*no of partitions of */
  bool holed_line = false;      //lost too many blobs
  int bestpart;                  /*biggest partition */
  int partsizes[MAXPARTS];       /*no in each partition */
  int lineheight;                /*guessed x-height */
  float jumplimit;               /*allowed delta change */
  int blobcount;                 /*no of blobs on line */
  int pointcount;                /*no of coords */
  int xstarts[SPLINESIZE + 1];   //segment boundaries
  int segments;                  //no of segments
 
                                 //no of blobs in row
  blobcount = row->blob_list ()->length ();
  // partition no of each blob
  std::vector<char> partids(blobcount);
  // useful sample points
  std::vector<int> xcoords(blobcount);
  // useful sample points
  std::vector<int> ycoords(blobcount);
  // edges of blob rectangles
  std::vector<TBOX> blobcoords(blobcount);
  // diffs from 1st approx
  std::vector<float> ydiffs(blobcount);
 
  lineheight = get_blob_coords(row, static_cast<int>(block->line_size), &blobcoords[0],
    holed_line, blobcount);
                                 /*limit for line change */
  jumplimit = lineheight * textord_oldbl_jumplimit;
  if (jumplimit < MINASCRISE)
    jumplimit = MINASCRISE;
 
  if (textord_oldbl_debug) {
    tprintf
      ("\nInput height=%g, Estimate x-height=%d pixels, jumplimit=%.2f\n",
      block->line_size, lineheight, jumplimit);
  }
  if (holed_line)
    make_holed_baseline(&blobcoords[0], blobcount, spline, &row->baseline,
      row->line_m ());
  else
    make_first_baseline(&blobcoords[0], blobcount,
      &xcoords[0], &ycoords[0], spline, &row->baseline, jumplimit);
#ifndef GRAPHICS_DISABLED
  if (textord_show_final_rows)
    row->baseline.plot (to_win, ScrollView::GOLDENROD);
#endif
  if (blobcount > 1) {
    bestpart = partition_line(&blobcoords[0], blobcount,
      &partcount, &partids[0], partsizes,
      &row->baseline, jumplimit, &ydiffs[0]);
    pointcount = partition_coords(&blobcoords[0], blobcount,
      &partids[0], bestpart, &xcoords[0], &ycoords[0]);
    segments = segment_spline(&blobcoords[0], blobcount,
      &xcoords[0], &ycoords[0], degree, pointcount, xstarts);
    if (!holed_line) {
      do {
        row->baseline = QSPLINE(xstarts, segments,
          &xcoords[0], &ycoords[0], pointcount, degree);
      }
      while (textord_oldbl_split_splines
        && split_stepped_spline (&row->baseline, jumplimit / 2,
        &xcoords[0], xstarts, segments));
    }
    find_lesser_parts(row, &blobcoords[0], blobcount,
                      &partids[0], partsizes, partcount, bestpart);
 
  }
  else {
    row->xheight = -1.0f;        /*failed */
    row->descdrop = 0.0f;
    row->ascrise = 0.0f;
  }
  row->baseline.extrapolate (row->line_m (),
    block->block->pdblk.bounding_box ().left (),
    block->block->pdblk.bounding_box ().right ());
 
  if (textord_really_old_xheight) {
    old_first_xheight (row, &blobcoords[0], lineheight,
      blobcount, &row->baseline, jumplimit);
  } else if (textord_old_xheight) {
    make_first_xheight (row, &blobcoords[0], lineheight, static_cast<int>(block->line_size),
                        blobcount, &row->baseline, jumplimit);
  } else {
    compute_row_xheight(row, block->block->classify_rotation(),
                        row->line_m(), block->line_size);
  }
}
 
}  // namespace tesseract.
 
 
/**********************************************************************
 * get_blob_coords
 *
 * Fill the blobcoords array with the coordinates of the blobs
 * in the row. The return value is the first guess at the line height.
 **********************************************************************/
 
int get_blob_coords(                    //get boxes
        TO_ROW* row,        //row to use
        int32_t lineheight,   //block level
        TBOX* blobcoords,    //output boxes
        bool& holed_line,  //lost a lot of blobs
        int& outcount       //no of real blobs
) {
                                 //blobs
  BLOBNBOX_IT blob_it = row->blob_list ();
  int blobindex;                 /*no along text line */
  int losscount;                 //lost blobs
  int maxlosscount;              //greatest lost blobs
                                 /*height stat collection */
  STATS heightstat (0, MAXHEIGHT);
 
  if (blob_it.empty ())
    return 0;                    //none
  maxlosscount = 0;
  losscount = 0;
  blob_it.mark_cycle_pt ();
  blobindex = 0;
  do {
    blobcoords[blobindex] = box_next_pre_chopped (&blob_it);
    if (blobcoords[blobindex].height () > lineheight * 0.25)
      heightstat.add (blobcoords[blobindex].height (), 1);
    if (blobindex == 0
      || blobcoords[blobindex].height () > lineheight * 0.25
    || blob_it.cycled_list ()) {
      blobindex++;               /*no of merged blobs */
      losscount = 0;
    }
    else {
      if (blobcoords[blobindex].height ()
        < blobcoords[blobindex].width () * oldbl_dot_error_size
        && blobcoords[blobindex].width ()
      < blobcoords[blobindex].height () * oldbl_dot_error_size) {
                                 //counts as dot
        blobindex++;
        losscount = 0;
      }
      else {
        losscount++;             //lost it
        if (losscount > maxlosscount)
                                 //remember max
            maxlosscount = losscount;
      }
    }
  }
  while (!blob_it.cycled_list ());
 
  holed_line = maxlosscount > oldbl_holed_losscount;
  outcount = blobindex;          /*total blobs */
 
  if (heightstat.get_total () > 1)
                                 /*guess x-height */
    return static_cast<int>(heightstat.ile (0.25));
  else
    return blobcoords[0].height ();
}
 
 
/**********************************************************************
 * make_first_baseline
 *
 * Make the first estimate at a baseline, either by shifting
 * a supplied previous spline, or by doing a piecewise linear
 * approximation using all the blobs.
 **********************************************************************/
 
void
make_first_baseline (            //initial approximation
TBOX blobcoords[],                /*blob bounding boxes */
int blobcount,                   /*no of blobcoords */
int xcoords[],                   /*coords for spline */
int ycoords[],                   /*approximator */
QSPLINE * spline,                /*initial spline */
QSPLINE * baseline,              /*output spline */
float jumplimit                  /*guess half descenders */
) {
  int leftedge;                  /*left edge of line */
  int rightedge;                 /*right edge of line */
  int blobindex;                 /*current blob */
  int segment;                   /*current segment */
  float prevy, thisy, nexty;     /*3 y coords */
  float y1, y2, y3;              /*3 smooth blobs */
  float maxmax, minmin;          /*absolute limits */
  int x2 = 0;                    /*right edge of old y3 */
  int ycount;                    /*no of ycoords in use */
  float yturns[SPLINESIZE];      /*y coords of turn pts */
  int xturns[SPLINESIZE];        /*xcoords of turn pts */
  int xstarts[SPLINESIZE + 1];
  int segments;                  //no of segments
  ICOORD shift;                  //shift of spline
 
  prevy = 0;
                                 /*left edge of row */
  leftedge = blobcoords[0].left ();
                                 /*right edge of line */
  rightedge = blobcoords[blobcount - 1].right ();
  if (spline == nullptr             /*no given spline */
    || spline->segments < 3      /*or trivial */
                                 /*or too non-overlap */
    || spline->xcoords[1] > leftedge + MAXOVERLAP * (rightedge - leftedge)
    || spline->xcoords[spline->segments - 1] < rightedge
  - MAXOVERLAP * (rightedge - leftedge)) {
    if (textord_oldbl_paradef)
      return;                    //use default
    xstarts[0] = blobcoords[0].left () - 1;
    for (blobindex = 0; blobindex < blobcount; blobindex++) {
      xcoords[blobindex] = (blobcoords[blobindex].left ()
        + blobcoords[blobindex].right ()) / 2;
      ycoords[blobindex] = blobcoords[blobindex].bottom ();
    }
    xstarts[1] = blobcoords[blobcount - 1].right () + 1;
    segments = 1;                /*no of segments */
 
                                 /*linear */
    *baseline = QSPLINE (xstarts, segments, xcoords, ycoords, blobcount, 1);
 
    if (blobcount >= 3) {
      y1 = y2 = y3 = 0.0f;
      ycount = 0;
      segment = 0;               /*no of segments */
      maxmax = minmin = 0.0f;
      thisy = ycoords[0] - baseline->y (xcoords[0]);
      nexty = ycoords[1] - baseline->y (xcoords[1]);
      for (blobindex = 2; blobindex < blobcount; blobindex++) {
        prevy = thisy;           /*shift ycoords */
        thisy = nexty;
        nexty = ycoords[blobindex] - baseline->y (xcoords[blobindex]);
                                 /*middle of smooth y */
        if (ABS (thisy - prevy) < jumplimit && ABS (thisy - nexty) < jumplimit) {
          y1 = y2;               /*shift window */
          y2 = y3;
          y3 = thisy;            /*middle point */
          ycount++;
                                 /*local max */
          if (ycount >= 3 && ((y1 < y2 && y2 >= y3)
                                 /*local min */
          || (y1 > y2 && y2 <= y3))) {
            if (segment < SPLINESIZE - 2) {
                                 /*turning pt */
              xturns[segment] = x2;
              yturns[segment] = y2;
              segment++;         /*no of spline segs */
            }
          }
          if (ycount == 1) {
            maxmax = minmin = y3;/*initialise limits */
          }
          else {
            if (y3 > maxmax)
              maxmax = y3;       /*biggest max */
            if (y3 < minmin)
              minmin = y3;       /*smallest min */
          }
                                 /*possible turning pt */
          x2 = blobcoords[blobindex - 1].right ();
        }
      }
 
      jumplimit *= 1.2;
                                 /*must be wavy */
      if (maxmax - minmin > jumplimit) {
        ycount = segment;        /*no of segments */
        for (blobindex = 0, segment = 1; blobindex < ycount;
        blobindex++) {
          if (yturns[blobindex] > minmin + jumplimit
          || yturns[blobindex] < maxmax - jumplimit) {
                                 /*significant peak */
            if (segment == 1
              || yturns[blobindex] > prevy + jumplimit
            || yturns[blobindex] < prevy - jumplimit) {
                                 /*different to previous */
              xstarts[segment] = xturns[blobindex];
              segment++;
              prevy = yturns[blobindex];
            }
                                 /*bigger max */
            else if ((prevy > minmin + jumplimit && yturns[blobindex] > prevy)
                                 /*smaller min */
            || (prevy < maxmax - jumplimit && yturns[blobindex] < prevy)) {
              xstarts[segment - 1] = xturns[blobindex];
                                 /*improved previous */
              prevy = yturns[blobindex];
            }
          }
        }
        xstarts[segment] = blobcoords[blobcount - 1].right () + 1;
        segments = segment;      /*no of segments */
                                 /*linear */
        *baseline = QSPLINE (xstarts, segments, xcoords, ycoords, blobcount, 1);
      }
    }
  }
  else {
    *baseline = *spline;         /*copy it */
    shift = ICOORD (0, static_cast<int16_t>(blobcoords[0].bottom ()
      - spline->y (blobcoords[0].right ())));
    baseline->move (shift);
  }
}
 
 
/**********************************************************************
 * make_holed_baseline
 *
 * Make the first estimate at a baseline, either by shifting
 * a supplied previous spline, or by doing a piecewise linear
 * approximation using all the blobs.
 **********************************************************************/
 
void
make_holed_baseline (            //initial approximation
TBOX blobcoords[],                /*blob bounding boxes */
int blobcount,                   /*no of blobcoords */
QSPLINE * spline,                /*initial spline */
QSPLINE * baseline,              /*output spline */
float gradient                   //of line
) {
  int leftedge;                  /*left edge of line */
  int rightedge;                 /*right edge of line */
  int blobindex;                 /*current blob */
  float x;                       //centre of row
  ICOORD shift;                  //shift of spline
 
  tesseract::DetLineFit lms;  // straight baseline
  int32_t xstarts[2];              //straight line
  double coeffs[3];
  float c;                       //line parameter
 
                                 /*left edge of row */
  leftedge = blobcoords[0].left ();
                                 /*right edge of line */
  rightedge = blobcoords[blobcount - 1].right();
  for (blobindex = 0; blobindex < blobcount; blobindex++) {
    lms.Add(ICOORD((blobcoords[blobindex].left() +
                    blobcoords[blobindex].right()) / 2,
                   blobcoords[blobindex].bottom()));
  }
  lms.ConstrainedFit(gradient, &c);
  xstarts[0] = leftedge;
  xstarts[1] = rightedge;
  coeffs[0] = 0;
  coeffs[1] = gradient;
  coeffs[2] = c;
  *baseline = QSPLINE (1, xstarts, coeffs);
  if (spline != nullptr             /*no given spline */
    && spline->segments >= 3     /*or trivial */
                                 /*or too non-overlap */
    && spline->xcoords[1] <= leftedge + MAXOVERLAP * (rightedge - leftedge)
    && spline->xcoords[spline->segments - 1] >= rightedge
  - MAXOVERLAP * (rightedge - leftedge)) {
    *baseline = *spline;         /*copy it */
    x = (leftedge + rightedge) / 2.0;
    shift = ICOORD (0, static_cast<int16_t>(gradient * x + c - spline->y (x)));
    baseline->move (shift);
  }
}
 
 
/**********************************************************************
 * partition_line
 *
 * Partition a row of blobs into different groups of continuous
 * y position. jumplimit specifies the max allowable limit on a jump
 * before a new partition is started.
 * The return value is the biggest partition
 **********************************************************************/
 
int
partition_line (                 //partition blobs
TBOX blobcoords[],                //bounding boxes
int blobcount,                   /*no of blobs on row */
int *numparts,                   /*number of partitions */
char partids[],                  /*partition no of each blob */
int partsizes[],                 /*no in each partition */
QSPLINE * spline,                /*curve to fit to */
float jumplimit,                 /*allowed delta change */
float ydiffs[]                   /*diff from spline */
) {
  int blobindex;                 /*no along text line */
  int bestpart;                  /*best new partition */
  int biggestpart;               /*part with most members */
  float diff;                    /*difference from line */
  int startx;                    /*index of start blob */
  float partdiffs[MAXPARTS];     /*step between parts */
 
  for (bestpart = 0; bestpart < MAXPARTS; bestpart++)
    partsizes[bestpart] = 0;     /*zero them all */
 
  startx = get_ydiffs (blobcoords, blobcount, spline, ydiffs);
  *numparts = 1;                 /*1 partition */
  bestpart = -1;                 /*first point */
  float drift = 0.0f;
  float last_delta = 0.0f;
  for (blobindex = startx; blobindex < blobcount; blobindex++) {
  /*do each blob in row */
    diff = ydiffs[blobindex];    /*diff from line */
    if (textord_oldbl_debug) {
      tprintf ("%d(%d,%d), ", blobindex,
        blobcoords[blobindex].left (),
        blobcoords[blobindex].bottom ());
    }
    bestpart = choose_partition(diff, partdiffs, bestpart, jumplimit,
                                &drift, &last_delta, numparts);
                                 /*record partition */
    partids[blobindex] = bestpart;
    partsizes[bestpart]++;       /*another in it */
  }
 
  bestpart = -1;                 /*first point */
  drift = 0.0f;
  last_delta = 0.0f;
  partsizes[0]--;                /*doing 1st pt again */
                                 /*do each blob in row */
  for (blobindex = startx; blobindex >= 0; blobindex--) {
    diff = ydiffs[blobindex];    /*diff from line */
    if (textord_oldbl_debug) {
      tprintf ("%d(%d,%d), ", blobindex,
        blobcoords[blobindex].left (),
        blobcoords[blobindex].bottom ());
    }
    bestpart = choose_partition(diff, partdiffs, bestpart, jumplimit,
                                &drift, &last_delta, numparts);
                                 /*record partition */
    partids[blobindex] = bestpart;
    partsizes[bestpart]++;       /*another in it */
  }
 
  for (biggestpart = 0, bestpart = 1; bestpart < *numparts; bestpart++)
    if (partsizes[bestpart] >= partsizes[biggestpart])
      biggestpart = bestpart;    /*new biggest */
  if (textord_oldbl_merge_parts)
    merge_oldbl_parts(blobcoords,
                      blobcount,
                      partids,
                      partsizes,
                      biggestpart,
                      jumplimit);
  return biggestpart;            /*biggest partition */
}
 
 
/**********************************************************************
 * merge_oldbl_parts
 *
 * For any adjacent group of blobs in a different part, put them in the
 * main part if they fit closely to neighbours in the main part.
 **********************************************************************/
 
void
merge_oldbl_parts (              //partition blobs
TBOX blobcoords[],                //bounding boxes
int blobcount,                   /*no of blobs on row */
char partids[],                  /*partition no of each blob */
int partsizes[],                 /*no in each partition */
int biggestpart,                 //major partition
float jumplimit                  /*allowed delta change */
) {
  bool found_one;               //found a bestpart blob
  bool close_one;               //found was close enough
  int blobindex;                 /*no along text line */
  int prevpart;                  //previous iteration
  int runlength;                 //no in this part
  float diff;                    /*difference from line */
  int startx;                    /*index of start blob */
  int test_blob;                 //another index
  FCOORD coord;                  //blob coordinate
  float m, c;                    //fitted line
  QLSQ stats;                    //line stuff
 
  prevpart = biggestpart;
  runlength = 0;
  startx = 0;
  for (blobindex = 0; blobindex < blobcount; blobindex++) {
    if (partids[blobindex] != prevpart) {
      //                      tprintf("Partition change at (%d,%d) from %d to %d after run of %d\n",
      //                              blobcoords[blobindex].left(),blobcoords[blobindex].bottom(),
      //                              prevpart,partids[blobindex],runlength);
      if (prevpart != biggestpart && runlength > MAXBADRUN) {
        stats.clear ();
        for (test_blob = startx; test_blob < blobindex; test_blob++) {
          coord = FCOORD ((blobcoords[test_blob].left ()
            + blobcoords[test_blob].right ()) / 2.0,
            blobcoords[test_blob].bottom ());
          stats.add (coord.x (), coord.y ());
        }
        stats.fit (1);
        m = stats.get_b ();
        c = stats.get_c ();
        if (textord_oldbl_debug)
          tprintf ("Fitted line y=%g x + %g\n", m, c);
        found_one = false;
        close_one = false;
        for (test_blob = 1; !found_one
          && (startx - test_blob >= 0
        || blobindex + test_blob <= blobcount); test_blob++) {
          if (startx - test_blob >= 0
          && partids[startx - test_blob] == biggestpart) {
            found_one = true;
            coord = FCOORD ((blobcoords[startx - test_blob].left ()
              + blobcoords[startx -
              test_blob].right ()) /
              2.0,
              blobcoords[startx -
              test_blob].bottom ());
            diff = m * coord.x () + c - coord.y ();
            if (textord_oldbl_debug)
              tprintf
                ("Diff of common blob to suspect part=%g at (%g,%g)\n",
                diff, coord.x (), coord.y ());
            if (diff < jumplimit && -diff < jumplimit)
              close_one = true;
          }
          if (blobindex + test_blob <= blobcount
          && partids[blobindex + test_blob - 1] == biggestpart) {
            found_one = true;
            coord =
              FCOORD ((blobcoords[blobindex + test_blob - 1].
              left () + blobcoords[blobindex + test_blob -
              1].right ()) / 2.0,
              blobcoords[blobindex + test_blob -
              1].bottom ());
            diff = m * coord.x () + c - coord.y ();
            if (textord_oldbl_debug)
              tprintf
                ("Diff of common blob to suspect part=%g at (%g,%g)\n",
                diff, coord.x (), coord.y ());
            if (diff < jumplimit && -diff < jumplimit)
              close_one = true;
          }
        }
        if (close_one) {
          if (textord_oldbl_debug)
            tprintf
              ("Merged %d blobs back into part %d from %d starting at (%d,%d)\n",
              runlength, biggestpart, prevpart,
              blobcoords[startx].left (),
              blobcoords[startx].bottom ());
                                 //switch sides
          partsizes[prevpart] -= runlength;
          for (test_blob = startx; test_blob < blobindex; test_blob++)
            partids[test_blob] = biggestpart;
        }
      }
      prevpart = partids[blobindex];
      runlength = 1;
      startx = blobindex;
    }
    else
      runlength++;
  }
}
 
 
/**********************************************************************
 * get_ydiffs
 *
 * Get the differences between the blobs and the spline,
 * putting them in ydiffs.  The return value is the index
 * of the blob in the middle of the "best behaved" region
 **********************************************************************/
 
int
get_ydiffs (                     //evaluate differences
TBOX blobcoords[],                //bounding boxes
int blobcount,                   /*no of blobs */
QSPLINE * spline,                /*approximating spline */
float ydiffs[]                   /*output */
) {
  int blobindex;                 /*current blob */
  int xcentre;                   /*xcoord */
  int lastx;                     /*last xcentre */
  float diffsum;                 /*sum of diffs */
  float diff;                    /*current difference */
  float drift;                   /*sum of spline steps */
  float bestsum;                 /*smallest diffsum */
  int bestindex;                 /*index of bestsum */
 
  diffsum = 0.0f;
  bestindex = 0;
  bestsum = static_cast<float>(INT32_MAX);
  drift = 0.0f;
  lastx = blobcoords[0].left ();
                                 /*do each blob in row */
  for (blobindex = 0; blobindex < blobcount; blobindex++) {
                                 /*centre of blob */
    xcentre = (blobcoords[blobindex].left () + blobcoords[blobindex].right ()) >> 1;
                                 //step functions in spline
    drift += spline->step (lastx, xcentre);
    lastx = xcentre;
    diff = blobcoords[blobindex].bottom ();
    diff -= spline->y (xcentre);
    diff += drift;
    ydiffs[blobindex] = diff;    /*store difference */
    if (blobindex > 2)
                                 /*remove old one */
      diffsum -= ABS (ydiffs[blobindex - 3]);
    diffsum += ABS (diff);       /*add new one */
    if (blobindex >= 2 && diffsum < bestsum) {
      bestsum = diffsum;         /*find min sum */
      bestindex = blobindex - 1; /*middle of set */
    }
  }
  return bestindex;
}
 
 
/**********************************************************************
 * choose_partition
 *
 * Choose a partition for the point and return the index.
 **********************************************************************/
 
int
choose_partition (               //select partition
float diff,             /*diff from spline */
float partdiffs[],               /*diff on all parts */
int lastpart,                    /*last assigned partition */
float jumplimit,                 /*new part threshold */
float* drift,
float* lastdelta,
int *partcount                   /*no of partitions */
) {
  int partition;                 /*partition no */
  int bestpart;                  /*best new partition */
  float bestdelta;               /*best gap from a part */
  float delta;                   /*diff from part */
 
  if (lastpart < 0) {
    partdiffs[0] = diff;
    lastpart = 0;                /*first point */
    *drift = 0.0f;
    *lastdelta = 0.0f;
  }
                                 /*adjusted diff from part */
  delta = diff - partdiffs[lastpart] - *drift;
  if (textord_oldbl_debug) {
    tprintf ("Diff=%.2f, Delta=%.3f, Drift=%.3f, ", diff, delta, *drift);
  }
  if (ABS (delta) > jumplimit / 2) {
                                 /*delta on part 0 */
    bestdelta = diff - partdiffs[0] - *drift;
    bestpart = 0;                /*0 best so far */
    for (partition = 1; partition < *partcount; partition++) {
      delta = diff - partdiffs[partition] - *drift;
      if (ABS (delta) < ABS (bestdelta)) {
        bestdelta = delta;
        bestpart = partition;    /*part with nearest jump */
      }
    }
    delta = bestdelta;
                                 /*too far away */
    if (ABS (bestdelta) > jumplimit
    && *partcount < MAXPARTS) {  /*and spare part left */
      bestpart = (*partcount)++; /*best was new one */
                                 /*start new one */
      partdiffs[bestpart] = diff - *drift;
      delta = 0.0f;
    }
  }
  else {
    bestpart = lastpart;         /*best was last one */
  }
 
  if (bestpart == lastpart
    && (ABS (delta - *lastdelta) < jumplimit / 2
    || ABS (delta) < jumplimit / 2))
                                 /*smooth the drift */
    *drift = (3 * *drift + delta) / 3;
  *lastdelta = delta;
 
  if (textord_oldbl_debug) {
    tprintf ("P=%d\n", bestpart);
  }
 
  return bestpart;
}
 
/**********************************************************************
 * partition_coords
 *
 * Get the x,y coordinates of all points in the bestpart and put them
 * in xcoords,ycoords. Return the number of points found.
 **********************************************************************/
 
int
partition_coords (               //find relevant coords
TBOX blobcoords[],                //bounding boxes
int blobcount,                   /*no of blobs in row */
char partids[],                  /*partition no of each blob */
int bestpart,                    /*best new partition */
int xcoords[],                   /*points to work on */
int ycoords[]                    /*points to work on */
) {
  int blobindex;                 /*no along text line */
  int pointcount;                /*no of points */
 
  pointcount = 0;
  for (blobindex = 0; blobindex < blobcount; blobindex++) {
    if (partids[blobindex] == bestpart) {
                                 /*centre of blob */
      xcoords[pointcount] = (blobcoords[blobindex].left () + blobcoords[blobindex].right ()) >> 1;
      ycoords[pointcount++] = blobcoords[blobindex].bottom ();
    }
  }
  return pointcount;             /*no of points found */
}
 
 
/**********************************************************************
 * segment_spline
 *
 * Segment the row at midpoints between maxima and minima of the x,y pairs.
 * The xstarts of the segments are returned and the number found.
 **********************************************************************/
 
int
segment_spline (                 //make xstarts
TBOX blobcoords[],                //boundign boxes
int blobcount,                   /*no of blobs in row */
int xcoords[],                   /*points to work on */
int ycoords[],                   /*points to work on */
int degree, int pointcount,      /*no of points */
int xstarts[]                    //result
) {
  int ptindex;                   /*no along text line */
  int segment;                   /*partition no */
  int lastmin, lastmax;          /*possible turn points */
  int turnpoints[SPLINESIZE];    /*good turning points */
  int turncount;                 /*no of turning points */
  int max_x;                     //max specified coord
 
  xstarts[0] = xcoords[0] - 1;   //leftmost defined pt
  max_x = xcoords[pointcount - 1] + 1;
  if (degree < 2)
    pointcount = 0;
  turncount = 0;                 /*no turning points yet */
  if (pointcount > 3) {
    ptindex = 1;
    lastmax = lastmin = 0;       /*start with first one */
    while (ptindex < pointcount - 1 && turncount < SPLINESIZE - 1) {
                                 /*minimum */
      if (ycoords[ptindex - 1] > ycoords[ptindex] && ycoords[ptindex] <= ycoords[ptindex + 1]) {
        if (ycoords[ptindex] < ycoords[lastmax] - TURNLIMIT) {
          if (turncount == 0 || turnpoints[turncount - 1] != lastmax)
                                 /*new max point */
            turnpoints[turncount++] = lastmax;
          lastmin = ptindex;     /*latest minimum */
        }
        else if (ycoords[ptindex] < ycoords[lastmin]) {
          lastmin = ptindex;     /*lower minimum */
        }
      }
 
                                 /*maximum */
      if (ycoords[ptindex - 1] < ycoords[ptindex] && ycoords[ptindex] >= ycoords[ptindex + 1]) {
        if (ycoords[ptindex] > ycoords[lastmin] + TURNLIMIT) {
          if (turncount == 0 || turnpoints[turncount - 1] != lastmin)
                                 /*new min point */
            turnpoints[turncount++] = lastmin;
          lastmax = ptindex;     /*latest maximum */
        }
        else if (ycoords[ptindex] > ycoords[lastmax]) {
          lastmax = ptindex;     /*higher maximum */
        }
      }
      ptindex++;
    }
                                 /*possible global min */
    if (ycoords[ptindex] < ycoords[lastmax] - TURNLIMIT
    && (turncount == 0 || turnpoints[turncount - 1] != lastmax)) {
      if (turncount < SPLINESIZE - 1)
                                 /*2 more turns */
        turnpoints[turncount++] = lastmax;
      if (turncount < SPLINESIZE - 1)
        turnpoints[turncount++] = ptindex;
    }
    else if (ycoords[ptindex] > ycoords[lastmin] + TURNLIMIT
      /*possible global max */
    && (turncount == 0 || turnpoints[turncount - 1] != lastmin)) {
      if (turncount < SPLINESIZE - 1)
                                 /*2 more turns */
        turnpoints[turncount++] = lastmin;
      if (turncount < SPLINESIZE - 1)
        turnpoints[turncount++] = ptindex;
    }
    else if (turncount > 0 && turnpoints[turncount - 1] == lastmin
    && turncount < SPLINESIZE - 1) {
      if (ycoords[ptindex] > ycoords[lastmax])
        turnpoints[turncount++] = ptindex;
      else
        turnpoints[turncount++] = lastmax;
    }
    else if (turncount > 0 && turnpoints[turncount - 1] == lastmax
    && turncount < SPLINESIZE - 1) {
      if (ycoords[ptindex] < ycoords[lastmin])
        turnpoints[turncount++] = ptindex;
      else
        turnpoints[turncount++] = lastmin;
    }
  }
 
  if (textord_oldbl_debug && turncount > 0)
    tprintf ("First turn is %d at (%d,%d)\n",
      turnpoints[0], xcoords[turnpoints[0]], ycoords[turnpoints[0]]);
  for (segment = 1; segment < turncount; segment++) {
                                 /*centre y coord */
    lastmax = (ycoords[turnpoints[segment - 1]] + ycoords[turnpoints[segment]]) / 2;
 
    /* fix alg so that it works with both rising and falling sections */
    if (ycoords[turnpoints[segment - 1]] < ycoords[turnpoints[segment]])
                                 /*find rising y centre */
      for (ptindex = turnpoints[segment - 1] + 1; ptindex < turnpoints[segment] && ycoords[ptindex + 1] <= lastmax; ptindex++);
    else
                                 /*find falling y centre */
      for (ptindex = turnpoints[segment - 1] + 1; ptindex < turnpoints[segment] && ycoords[ptindex + 1] >= lastmax; ptindex++);
 
                                 /*centre x */
    xstarts[segment] = (xcoords[ptindex - 1] + xcoords[ptindex]
      + xcoords[turnpoints[segment - 1]]
      + xcoords[turnpoints[segment]] + 2) / 4;
    /*halfway between turns */
    if (textord_oldbl_debug)
      tprintf ("Turn %d is %d at (%d,%d), mid pt is %d@%d, final @%d\n",
        segment, turnpoints[segment],
        xcoords[turnpoints[segment]], ycoords[turnpoints[segment]],
        ptindex - 1, xcoords[ptindex - 1], xstarts[segment]);
  }
 
  xstarts[segment] = max_x;
  return segment;                /*no of splines */
}
 
 
/**********************************************************************
 * split_stepped_spline
 *
 * Re-segment the spline in cases where there is a big step function.
 * Return true if any were done.
 **********************************************************************/
 
bool
split_stepped_spline(           //make xstarts
        QSPLINE* baseline,              //current shot
        float jumplimit,                 //max step function
        int* xcoords,                   /*points to work on */
        int* xstarts,                   //result
        int& segments                    //no of segments
) {
  bool doneany;                 //return value
  int segment;                   /*partition no */
  int startindex, centreindex, endindex;
  float leftcoord, rightcoord;
  int leftindex, rightindex;
  float step;                    //spline step
 
  doneany = false;
  startindex = 0;
  for (segment = 1; segment < segments - 1; segment++) {
    step = baseline->step ((xstarts[segment - 1] + xstarts[segment]) / 2.0,
      (xstarts[segment] + xstarts[segment + 1]) / 2.0);
    if (step < 0)
      step = -step;
    if (step > jumplimit) {
      while (xcoords[startindex] < xstarts[segment - 1])
        startindex++;
      centreindex = startindex;
      while (xcoords[centreindex] < xstarts[segment])
        centreindex++;
      endindex = centreindex;
      while (xcoords[endindex] < xstarts[segment + 1])
        endindex++;
      if (segments >= SPLINESIZE) {
        if (textord_debug_baselines)
          tprintf ("Too many segments to resegment spline!!\n");
      }
      else if (endindex - startindex >= textord_spline_medianwin * 3) {
        while (centreindex - startindex <
          textord_spline_medianwin * 3 / 2)
          centreindex++;
        while (endindex - centreindex <
          textord_spline_medianwin * 3 / 2)
          centreindex--;
        leftindex = (startindex + startindex + centreindex) / 3;
        rightindex = (centreindex + endindex + endindex) / 3;
        leftcoord =
          (xcoords[startindex] * 2 + xcoords[centreindex]) / 3.0;
        rightcoord =
          (xcoords[centreindex] + xcoords[endindex] * 2) / 3.0;
        while (xcoords[leftindex] > leftcoord
          && leftindex - startindex > textord_spline_medianwin)
          leftindex--;
        while (xcoords[leftindex] < leftcoord
          && centreindex - leftindex >
          textord_spline_medianwin / 2)
          leftindex++;
        if (xcoords[leftindex] - leftcoord >
          leftcoord - xcoords[leftindex - 1])
          leftindex--;
        while (xcoords[rightindex] > rightcoord
          && rightindex - centreindex >
          textord_spline_medianwin / 2)
          rightindex--;
        while (xcoords[rightindex] < rightcoord
          && endindex - rightindex > textord_spline_medianwin)
          rightindex++;
        if (xcoords[rightindex] - rightcoord >
          rightcoord - xcoords[rightindex - 1])
          rightindex--;
        if (textord_debug_baselines)
          tprintf ("Splitting spline at %d with step %g at (%d,%d)\n",
            xstarts[segment],
            baseline->
            step ((xstarts[segment - 1] +
            xstarts[segment]) / 2.0,
            (xstarts[segment] +
            xstarts[segment + 1]) / 2.0),
            (xcoords[leftindex - 1] + xcoords[leftindex]) / 2,
            (xcoords[rightindex - 1] + xcoords[rightindex]) / 2);
        insert_spline_point (xstarts, segment,
          (xcoords[leftindex - 1] +
          xcoords[leftindex]) / 2,
          (xcoords[rightindex - 1] +
          xcoords[rightindex]) / 2, segments);
        doneany = true;
      }
      else if (textord_debug_baselines) {
        tprintf
          ("Resegmenting spline failed - insufficient pts (%d,%d,%d,%d)\n",
          startindex, centreindex, endindex,
          (int32_t) textord_spline_medianwin);
      }
    }
    //              else tprintf("Spline step at %d is %g\n",
    //                      xstarts[segment],
    //                      baseline->step((xstarts[segment-1]+xstarts[segment])/2.0,
    //                      (xstarts[segment]+xstarts[segment+1])/2.0));
  }
  return doneany;
}
 
 
/**********************************************************************
 * insert_spline_point
 *
 * Insert a new spline point and shuffle up the others.
 **********************************************************************/
 
void
insert_spline_point (            //get descenders
int xstarts[],                   //starts to shuffle
int segment,                     //insertion pt
int coord1,                      //coords to add
int coord2, int &segments        //total segments
) {
  int index;                     //for shuffling
 
  for (index = segments; index > segment; index--)
    xstarts[index + 1] = xstarts[index];
  segments++;
  xstarts[segment] = coord1;
  xstarts[segment + 1] = coord2;
}
 
 
/**********************************************************************
 * find_lesser_parts
 *
 * Average the step from the spline for the other partitions
 * and find the commonest partition which has a descender.
 **********************************************************************/
 
void
find_lesser_parts (              //get descenders
TO_ROW * row,                    //row to process
TBOX blobcoords[],                //bounding boxes
int blobcount,                   /*no of blobs */
char partids[],                  /*partition of each blob */
int partsizes[],                 /*size of each part */
int partcount,                   /*no of partitions */
int bestpart                     /*biggest partition */
) {
  int blobindex;                 /*index of blob */
  int partition;                 /*current partition */
  int xcentre;                   /*centre of blob */
  int poscount;                  /*count of best up step */
  int negcount;                  /*count of best down step */
  float partsteps[MAXPARTS];     /*average step to part */
  float bestneg;                 /*best down step */
  int runlength;                 /*length of bad run */
  int biggestrun;                /*biggest bad run */
 
  biggestrun = 0;
  for (partition = 0; partition < partcount; partition++)
    partsteps[partition] = 0.0;  /*zero accumulators */
  for (runlength = 0, blobindex = 0; blobindex < blobcount; blobindex++) {
    xcentre = (blobcoords[blobindex].left ()
      + blobcoords[blobindex].right ()) >> 1;
                                 /*in other parts */
    int part_id =
        static_cast<int>(static_cast<unsigned char>(partids[blobindex]));
    if (part_id != bestpart) {
      runlength++;               /*run of non bests */
      if (runlength > biggestrun)
        biggestrun = runlength;
      partsteps[part_id] += blobcoords[blobindex].bottom()
        - row->baseline.y(xcentre);
    }
    else
      runlength = 0;
  }
  if (biggestrun > MAXBADRUN)
    row->xheight = -1.0f;        /*failed */
  else
    row->xheight = 1.0f;         /*success */
  poscount = negcount = 0;
  bestneg = 0.0;       /*no step yet */
  for (partition = 0; partition < partcount; partition++) {
    if (partition != bestpart) {
      // by jetsoft divide by zero possible
      if (partsizes[partition] == 0)
        partsteps[partition] = 0;
      else
        partsteps[partition] /= partsizes[partition];
      //
 
      if (partsteps[partition] >= MINASCRISE
      && partsizes[partition] > poscount) {
        poscount = partsizes[partition];
      }
      if (partsteps[partition] <= -MINASCRISE
      && partsizes[partition] > negcount) {
                                 /*ascender rise */
        bestneg = partsteps[partition];
                                 /*2nd most popular */
        negcount = partsizes[partition];
      }
    }
  }
                                 /*average x-height */
  partsteps[bestpart] /= blobcount;
  row->descdrop = bestneg;
}
 
 
/**********************************************************************
 * old_first_xheight
 *
 * Makes an x-height spline by copying the baseline and shifting it.
 * It estimates the x-height across the line to use as the shift.
 * It also finds the ascender height if it can.
 **********************************************************************/
 
void
old_first_xheight (              //the wiseowl way
TO_ROW * row,                    /*current row */
TBOX blobcoords[],                /*blob bounding boxes */
int initialheight,               //initial guess
int blobcount,                   /*blobs in blobcoords */
QSPLINE * baseline,              /*established */
float jumplimit                  /*min ascender height */
) {
  int blobindex; /*current blob */
                 /*height statistics */
  STATS heightstat (0, MAXHEIGHT);
  int height;                    /*height of blob */
  int xcentre;                   /*centre of blob */
  int lineheight;                /*approx xheight */
  float ascenders;               /*ascender sum */
  int asccount;                  /*no of ascenders */
  float xsum;                    /*xheight sum */
  int xcount;                    /*xheight count */
  float diff;                    /*height difference */
 
  if (blobcount > 1) {
    for (blobindex = 0; blobindex < blobcount; blobindex++) {
      xcentre = (blobcoords[blobindex].left ()
        + blobcoords[blobindex].right ()) / 2;
                                 /*height of blob */
      height = static_cast<int>(blobcoords[blobindex].top () - baseline->y (xcentre) + 0.5);
      if (height > initialheight * oldbl_xhfract
        && height > textord_min_xheight)
        heightstat.add (height, 1);
    }
    if (heightstat.get_total () > 3) {
      lineheight = static_cast<int>(heightstat.ile (0.25));
      if (lineheight <= 0)
        lineheight = static_cast<int>(heightstat.ile (0.5));
    }
    else
      lineheight = initialheight;
  }
  else {
    lineheight = static_cast<int>(blobcoords[0].top ()
      - baseline->y ((blobcoords[0].left ()
      + blobcoords[0].right ()) / 2) +
      0.5);
  }
 
  xsum = 0.0f;
  xcount = 0;
  for (ascenders = 0.0f, asccount = 0, blobindex = 0; blobindex < blobcount;
  blobindex++) {
    xcentre = (blobcoords[blobindex].left ()
      + blobcoords[blobindex].right ()) / 2;
    diff = blobcoords[blobindex].top () - baseline->y (xcentre);
                                 /*is it ascender */
    if (diff > lineheight + jumplimit) {
      ascenders += diff;
      asccount++;                /*count ascenders */
    }
    else if (diff > lineheight - jumplimit) {
      xsum += diff;              /*mean xheight */
      xcount++;
    }
  }
  if (xcount > 0)
    xsum /= xcount;              /*average xheight */
  else
    xsum = static_cast<float>(lineheight);   /*guess it */
  row->xheight *= xsum;
  if (asccount > 0)
    row->ascrise = ascenders / asccount - xsum;
  else
    row->ascrise = 0.0f;         /*had none */
  if (row->xheight == 0)
    row->xheight = -1.0f;
}
 
 
/**********************************************************************
 * make_first_xheight
 *
 * Makes an x-height spline by copying the baseline and shifting it.
 * It estimates the x-height across the line to use as the shift.
 * It also finds the ascender height if it can.
 **********************************************************************/
 
void
make_first_xheight (             //find xheight
TO_ROW * row,                    /*current row */
TBOX blobcoords[],                /*blob bounding boxes */
int lineheight,                  //initial guess
int init_lineheight,             //block level guess
int blobcount,                   /*blobs in blobcoords */
QSPLINE * baseline,              /*established */
float jumplimit                  /*min ascender height */
) {
  STATS heightstat (0, HEIGHTBUCKETS);
  int lefts[HEIGHTBUCKETS];
  int rights[HEIGHTBUCKETS];
  int modelist[MODENUM];
  int blobindex;
  int mode_count;                //blobs to count in thr
  int sign_bit;
  int mode_threshold;
  const int kBaselineTouch = 2;  // This really should change with resolution.
  const int kGoodStrength = 8;  // Strength of baseline-touching heights.
  const float kMinHeight = 0.25;  // Min fraction of lineheight to use.
 
  sign_bit = row->xheight > 0 ? 1 : -1;
 
  memset(lefts, 0, HEIGHTBUCKETS * sizeof(lefts[0]));
  memset(rights, 0, HEIGHTBUCKETS * sizeof(rights[0]));
  mode_count = 0;
  for (blobindex = 0; blobindex < blobcount; blobindex++) {
    int xcenter = (blobcoords[blobindex].left () +
        blobcoords[blobindex].right ()) / 2;
    float base = baseline->y(xcenter);
    float bottomdiff = fabs(base - blobcoords[blobindex].bottom());
    int strength = textord_ocropus_mode &&
                   bottomdiff <= kBaselineTouch ? kGoodStrength : 1;
    int height = static_cast<int>(blobcoords[blobindex].top () - base + 0.5);
    if (blobcoords[blobindex].height () > init_lineheight * kMinHeight) {
      if (height > lineheight * oldbl_xhfract
        && height > textord_min_xheight) {
        heightstat.add (height, strength);
        if (height < HEIGHTBUCKETS) {
          if (xcenter > rights[height])
            rights[height] = xcenter;
          if (xcenter > 0 && (lefts[height] == 0 || xcenter < lefts[height]))
            lefts[height] = xcenter;
        }
      }
      mode_count += strength;
    }
  }
 
  mode_threshold = static_cast<int>(blobcount * 0.1);
  if (oldbl_dot_error_size > 1 || oldbl_xhfix)
    mode_threshold = static_cast<int>(mode_count * 0.1);
 
  if (textord_oldbl_debug) {
    tprintf ("blobcount=%d, mode_count=%d, mode_t=%d\n",
      blobcount, mode_count, mode_threshold);
  }
  find_top_modes(&heightstat, HEIGHTBUCKETS, modelist, MODENUM);
  if (textord_oldbl_debug) {
    for (blobindex = 0; blobindex < MODENUM; blobindex++)
      tprintf ("mode[%d]=%d ", blobindex, modelist[blobindex]);
    tprintf ("\n");
  }
  pick_x_height(row, modelist, lefts, rights, &heightstat, mode_threshold);
 
  if (textord_oldbl_debug)
    tprintf ("Output xheight=%g\n", row->xheight);
  if (row->xheight < 0 && textord_oldbl_debug)
    tprintf ("warning: Row Line height < 0; %4.2f\n", row->xheight);
 
  if (sign_bit < 0)
    row->xheight = -row->xheight;
}
 
/**********************************************************************
 * find_top_modes
 *
 * Fill the input array with the indices of the top ten modes of the
 * input distribution.
 **********************************************************************/
 
const int kMinModeFactorOcropus = 32;
const int kMinModeFactor = 12;
 
void
find_top_modes (                 //get modes
STATS * stats,                   //stats to hack
int statnum,                     //no of piles
int modelist[], int modenum      //no of modes to get
) {
  int mode_count;
  int last_i = 0;
  int last_max = INT32_MAX;
  int i;
  int mode;
  int total_max = 0;
  int mode_factor = textord_ocropus_mode ?
                    kMinModeFactorOcropus : kMinModeFactor;
 
  for (mode_count = 0; mode_count < modenum; mode_count++) {
    mode = 0;
    for (i = 0; i < statnum; i++) {
      if (stats->pile_count (i) > stats->pile_count (mode)) {
        if ((stats->pile_count (i) < last_max) ||
        ((stats->pile_count (i) == last_max) && (i > last_i))) {
          mode = i;
        }
      }
    }
    last_i = mode;
    last_max = stats->pile_count (last_i);
    total_max += last_max;
    if (last_max <= total_max / mode_factor)
      mode = 0;
    modelist[mode_count] = mode;
  }
}
 
 
/**********************************************************************
 * pick_x_height
 *
 * Choose based on the height modes the best x height value.
 **********************************************************************/
 
void pick_x_height(TO_ROW * row,                    //row to do
                   int modelist[],
                   int lefts[], int rights[],
                   STATS * heightstat,
                   int mode_threshold) {
  int x;
  int y;
  int z;
  float ratio;
  int found_one_bigger = false;
  int best_x_height = 0;
  int best_asc = 0;
  int num_in_best;
 
  for (x = 0; x < MODENUM; x++) {
    for (y = 0; y < MODENUM; y++) {
      /* Check for two modes */
      if (modelist[x] && modelist[y] &&
          heightstat->pile_count (modelist[x]) > mode_threshold &&
          (!textord_ocropus_mode ||
                  std::min(rights[modelist[x]], rights[modelist[y]]) >
                   std::max(lefts[modelist[x]], lefts[modelist[y]]))) {
        ratio = static_cast<float>(modelist[y]) / static_cast<float>(modelist[x]);
        if (1.2 < ratio && ratio < 1.8) {
          /* Two modes found */
          best_x_height = modelist[x];
          num_in_best = heightstat->pile_count (modelist[x]);
 
          /* Try to get one higher */
          do {
            found_one_bigger = false;
            for (z = 0; z < MODENUM; z++) {
              if (modelist[z] == best_x_height + 1 &&
                  (!textord_ocropus_mode ||
                          std::min(rights[modelist[x]], rights[modelist[y]]) >
                            std::max(lefts[modelist[x]], lefts[modelist[y]]))) {
                ratio = static_cast<float>(modelist[y]) / static_cast<float>(modelist[z]);
                if ((1.2 < ratio && ratio < 1.8) &&
                               /* Should be half of best */
                    heightstat->pile_count (modelist[z]) >
                    num_in_best * 0.5) {
                  best_x_height++;
                  found_one_bigger = true;
                  break;
                }
              }
            }
          }
          while (found_one_bigger);
 
          /* try to get a higher ascender */
 
          best_asc = modelist[y];
          num_in_best = heightstat->pile_count (modelist[y]);
 
          /* Try to get one higher */
          do {
            found_one_bigger = false;
            for (z = 0; z < MODENUM; z++) {
              if (modelist[z] > best_asc &&
                  (!textord_ocropus_mode ||
                          std::min(rights[modelist[x]], rights[modelist[y]]) >
                            std::max(lefts[modelist[x]], lefts[modelist[y]]))) {
                ratio = static_cast<float>(modelist[z]) / static_cast<float>(best_x_height);
                if ((1.2 < ratio && ratio < 1.8) &&
                               /* Should be half of best */
                    heightstat->pile_count (modelist[z]) >
                    num_in_best * 0.5) {
                  best_asc = modelist[z];
                  found_one_bigger = true;
                  break;
                }
              }
            }
          }
          while (found_one_bigger);
 
          row->xheight = static_cast<float>(best_x_height);
          row->ascrise = static_cast<float>(best_asc) - best_x_height;
          return;
        }
      }
    }
  }
 
  best_x_height = modelist[0];   /* Single Mode found */
  num_in_best = heightstat->pile_count (best_x_height);
  do {
                                 /* Try to get one higher */
    found_one_bigger = false;
    for (z = 1; z < MODENUM; z++) {
      /* Should be half of best */
      if ((modelist[z] == best_x_height + 1) &&
      (heightstat->pile_count (modelist[z]) > num_in_best * 0.5)) {
        best_x_height++;
        found_one_bigger = true;
        break;
      }
    }
  }
  while (found_one_bigger);
 
  row->ascrise = 0.0f;
  row->xheight = static_cast<float>(best_x_height);
  if (row->xheight == 0)
    row->xheight = -1.0f;
}