blkocc.cpp

一ＯＣＲ的相关资料。．希望对研究ＯＣＲ的朋友有所帮助．

                    &next_band,
                    &min_x,
                    &max_x,
                    &increment,
                    exit_pt);
        pt_it.mark_cycle_pt ();

        // Found the first real transition, so start walking the outline from here.

        do {
          prev_band = band;
          band = band + increment;

          while (band != next_band) {
            temp_pt = entry_pt;
            entry_pt = exit_pt;
            exit_pt = temp_pt;
            min_x = max_x = entry_pt->x ();

            find_trans_point (&pt_it, band, band + increment,
              exit_pt);
            maintain_limits (&min_x, &max_x, exit_pt->x ());

            record_region (band,
              min_x,
              max_x,
              find_region_type (prev_band,
              band,
              band + increment,
              entry_pt->x (),
              exit_pt->x ()),
              region_occ_list);
            prev_band = band;
            band = band + increment;
          }

          temp_pt = entry_pt;
          entry_pt = exit_pt;
          exit_pt = temp_pt;
          min_x = max_x = entry_pt->x ();
          next_region(&pt_it,
                      band,
                      &next_band,
                      &min_x,
                      &max_x,
                      &increment,
                      exit_pt);

          record_region (band,
            min_x,
            max_x,
            find_region_type (prev_band,
            band,
            band + increment,
            entry_pt->x (),
            exit_pt->x ()),
            region_occ_list);
        }
        while (!pt_it.cycled_list ());
      }
    }
  }
}


void record_region(  //add region on list
                   INT16 band,
                   float new_min,
                   float new_max,
                   INT16 region_type,
                   REGION_OCC_LIST *region_occ_list) {
  REGION_OCC_IT it (&(region_occ_list[band]));

  //   if (wordocc_debug_on && blockocc_show_result)
  //         fprintf( db_win, "\nBand %d, region type %d, from %f to %f",
  //                                 band, region_type, new_min, new_max );

  if ((region_type == REGION_TYPE_UPPER_UNBOUND) ||
    (region_type == REGION_TYPE_LOWER_UNBOUND) ||
    (region_type == REGION_TYPE_EMPTY))
    return;

  if (it.empty ()) {
    it.add_after_stay_put (new REGION_OCC (new_min, new_max, region_type));
  }
  else {

    /* Insert in sorted order of average limit */

    while ((new_min + new_max > it.data ()->min_x + it.data ()->max_x) &&
      (!it.at_last ()))
      it.forward ();

    if ((it.at_last ()) &&       //at the end
      (new_min + new_max > it.data ()->min_x + it.data ()->max_x))
      //new range > current
      it.add_after_stay_put (new REGION_OCC (new_min,
        new_max, region_type));
    else {
      it.add_before_stay_put (new REGION_OCC (new_min,
        new_max, region_type));
    }
  }
}


INT16 find_containing_maximal_band(  //find range's band
                                   float y1,
                                   float y2,
                                   BOOL8 *doubly_contained) {
  INT16 band;

  *doubly_contained = FALSE;

  for (band = 1; band <= blockocc_band_count; band++) {
    if (bands[band].range_in_maximal (y1, y2)) {
      if ((band < blockocc_band_count) &&
        (bands[band + 1].range_in_maximal (y1, y2)))
        *doubly_contained = TRUE;
      return band;
    }
  }
  return UNDEFINED_BAND;
}


void find_significant_line(POLYPT_IT it, INT16 *band) { 

  /* Look for a line which significantly occupies at least one band. I.e. part
  of the line is in the non-margin part of the band. */

  *band = find_overlapping_minimal_band (it.data ()->pos.y (),
    it.data ()->pos.y () +
    it.data ()->vec.y ());

  while (*band == UNDEFINED_BAND) {
    it.forward ();
    *band = find_overlapping_minimal_band (it.data ()->pos.y (),
      it.data ()->pos.y () +
      it.data ()->vec.y ());
  }
}


INT16 find_overlapping_minimal_band(  //find range's band
                                    float y1,
                                    float y2) {
  INT16 band;

  for (band = 1; band <= blockocc_band_count; band++) {
    if (bands[band].range_overlaps_minimal (y1, y2))
      return band;
  }
  return UNDEFINED_BAND;
}


INT16 find_region_type(INT16 entry_band,
                       INT16 current_band,
                       INT16 exit_band,
                       float entry_x,
                       float exit_x) {
  if (entry_band > exit_band)
    return REGION_TYPE_OPEN_RIGHT;
  if (entry_band < exit_band)
    return REGION_TYPE_OPEN_LEFT;
  if (entry_x == exit_x)
    return REGION_TYPE_EMPTY;
  if (entry_band > current_band) {
    if (entry_x < exit_x)
      return REGION_TYPE_UPPER_BOUND;
    else
      return REGION_TYPE_UPPER_UNBOUND;
  }
  else {
    if (entry_x > exit_x)
      return REGION_TYPE_LOWER_BOUND;
    else
      return REGION_TYPE_LOWER_UNBOUND;
  }
}


void find_trans_point(POLYPT_IT *pt_it,
                      INT16 current_band,
                      INT16 next_band,
                      FCOORD *transition_pt) {
  float x1, x2, y1, y2;          // points of edge
  float gradient;                // m in y = mx + c
  float offset;                  // c in y = mx + c

  if (current_band < next_band)
    transition_pt->set_y (bands[current_band].max);
  //going up
  else
    transition_pt->set_y (bands[current_band].min);
  //going down

  x1 = pt_it->data ()->pos.x ();
  x2 = x1 + pt_it->data ()->vec.x ();
  y1 = pt_it->data ()->pos.y ();
  y2 = y1 + pt_it->data ()->vec.y ();

  if (x1 == x2)
    transition_pt->set_x (x1);   //avoid div by 0
  else {
    if (y1 == y2)                //avoid div by 0
      transition_pt->set_x ((x1 + x2) / 2.0);
    else {
      gradient = (y1 - y2) / (float) (x1 - x2);
      offset = y1 - x1 * gradient;
      transition_pt->set_x ((transition_pt->y () - offset) / gradient);
    }
  }
}


void next_region(POLYPT_IT *start_pt_it,
                 INT16 start_band,
                 INT16 *to_band,
                 float *min_x,
                 float *max_x,
                 INT16 *increment,
                 FCOORD *exit_pt) {
  /*
  Given an edge and a band which the edge significantly occupies, find the
  significant end of the region containing the band. I.e. find an edge which
  points to another band such that the outline subsequetly moves significantly
  out of the starting band.

  Note that we can assume that we are significantly inside the current band to
  start with because the edges passed will be from previous calls to this
  routine apart from the first - the result of which is only used to establish
  the start of the first region.
  */

  INT16 band;                    //band of current edge
  INT16 prev_band = start_band;  //band of prev edge
                                 //edge crossing out
  POLYPT_IT last_transition_out_it;
                                 //band it pts to
  INT16 last_trans_out_to_band = 0;
  float ext_min_x = 0.0f;
  float ext_max_x = 0.0f;

  start_pt_it->forward ();
  band = find_band (start_pt_it->data ()->pos.y ());

  while ((band == start_band) ||
  bands[start_band].in_maximal (start_pt_it->data ()->pos.y ())) {
    if (band == start_band) {
                                 //Return to start band
      if (prev_band != start_band) {
        *min_x = ext_min_x;
        *max_x = ext_max_x;
      }
      maintain_limits (min_x, max_x, start_pt_it->data ()->pos.x ());
    }
    else {
      if (prev_band == start_band) {
                                 //Exit from start band
                                 //so remember edge
        last_transition_out_it = *start_pt_it;
                                 //before we left
        last_transition_out_it.backward ();
                                 //and band it pts to
        last_trans_out_to_band = band;
        ext_min_x = *min_x;
        ext_max_x = *max_x;
      }
      maintain_limits (&ext_min_x, &ext_max_x,
        start_pt_it->data ()->pos.x ());
    }
    prev_band = band;
    start_pt_it->forward ();
    band = find_band (start_pt_it->data ()->pos.y ());
  }

  if (prev_band == start_band) { //exit from start band
    *to_band = band;
                                 //so remember edge
    last_transition_out_it = *start_pt_it;
                                 //before we left
    last_transition_out_it.backward ();
  }
  else {
    *to_band = last_trans_out_to_band;
  }

  if (*to_band > start_band)
    *increment = 1;
  else
    *increment = -1;

  find_trans_point (&last_transition_out_it, start_band,
    start_band + *increment, exit_pt);
  maintain_limits (min_x, max_x, exit_pt->x ());
  *start_pt_it = last_transition_out_it;
}


INT16 find_band(  // find POINT's band
                float y) {
  INT16 band;

  for (band = 1; band <= blockocc_band_count; band++) {
    if (bands[band].in_nominal (y))
      return band;
  }
  BLOCKOCC.error ("find_band", ABORT, "Cant find band for %d", y);
  return 0;
}


void compress_region_list(  // join open regions
                          REGION_OCC_LIST *region_occ_list) {
  REGION_OCC_IT it (&(region_occ_list[0]));
  REGION_OCC *open_right = NULL;

  INT16 i = 0;

  for (i = 0; i <= blockocc_band_count; i++) {
    it.set_to_list (&(region_occ_list[i]));
    if (!it.empty ()) {
      /* First check for left right pairs. Merge them into the open right and delete
      the open left. */
      open_right = NULL;
      for (it.mark_cycle_pt (); !it.cycled_list (); it.forward ()) {
        switch (it.data ()->region_type) {
          case REGION_TYPE_OPEN_RIGHT:
          {
            if (open_right != NULL)
              BLOCKOCC.error ("compress_region_list", ABORT,
                "unmatched right");
            else
              open_right = it.data ();
            break;
          }
          case REGION_TYPE_OPEN_LEFT:
          {
            if (open_right == NULL)
              BLOCKOCC.error ("compress_region_list", ABORT,
                "unmatched left");
            else {
              open_right->max_x = it.data ()->max_x;
              open_right = NULL;
              delete it.extract ();
            }
            break;
          }
          default:
            break;
        }
      }
      if (open_right != NULL)
        BLOCKOCC.error ("compress_region_list", ABORT,
          "unmatched right remaining");

      /* Now cycle the list again, merging and deleting any redundant regions */
      it.move_to_first ();
      open_right = it.data ();
      while (!it.at_last ()) {
        it.forward ();
        if (it.data ()->min_x <= open_right->max_x) {
        // Overlaps
          if (it.data ()->max_x > open_right->max_x)
            open_right->max_x = it.data ()->max_x;
          // Extend
          delete it.extract ();
        }
        else
          open_right = it.data ();
      }
    }
  }
}


void find_fbox(OUTLINE_IT *out_it,
               float *min_x,
               float *min_y,
               float *max_x,
               float *max_y) {
  POLYPT_IT pt_it = out_it->data ()->polypts ();
  FCOORD pt;
  *min_x = 9999.0f;
  *min_y = 9999.0f;
  *max_x = 0.0f;
  *max_y = 0.0f;

  for (pt_it.mark_cycle_pt (); !pt_it.cycled_list (); pt_it.forward ()) {
    pt = pt_it.data ()->pos;
    maintain_limits (min_x, max_x, pt.x ());
    maintain_limits (min_y, max_y, pt.y ());
  }
}


void maintain_limits(float *min_x, float *max_x, float x) { 
  if (x > *max_x)
    *max_x = x;
  if (x < *min_x)
    *min_x = x;
}