C++ BLOBNBOX::leader_on_left方法代码示例

//.........这里部分代码省略.........
                nbox.left(), nbox.bottom(), nbox.right(), nbox.top());
      break;  // Gone far enough.
    }
    // It is CRITICAL to ensure that forward progress is made, (strictly
    // in/decreasing n_y) or the caller could loop infinitely, while
    // waiting for a sequence of blobs in a line to end.
    // NextVerticalSearch alone does not guarantee this, as there may be
    // more than one blob in a grid cell. See comment in AlignTabs.
    if ((n_y < start_y) != top_to_bottom || nbox.y_overlap(box))
      continue;  // Only look in the required direction.
    if (result != nullptr && result->bounding_box().y_gap(nbox) > gridsize())
      return result;  // This result is clear.
    if (backup_result != nullptr && p.ragged && result == nullptr &&
        backup_result->bounding_box().y_gap(nbox) > gridsize())
      return backup_result;  // This result is clear.

    // If the neighbouring blob is the wrong side of a separator line, then it
    // "doesn't exist" as far as we are concerned.
    int x_at_n_y = x_start + (n_y - start_y) * p.vertical.x() / p.vertical.y();
    if (x_at_n_y < neighbour->left_crossing_rule() ||
        x_at_n_y > neighbour->right_crossing_rule())
      continue;  // Separator line in the way.
    int n_left = nbox.left();
    int n_right = nbox.right();
    int n_x = p.right_tab ? n_right : n_left;
    if (WithinTestRegion(2, x_start, start_y))
      tprintf("neighbour at (%d,%d)->(%d,%d), n_x=%d, n_y=%d, xatn=%d\n",
              nbox.left(), nbox.bottom(), nbox.right(), nbox.top(),
              n_x, n_y, x_at_n_y);
    if (p.right_tab &&
        n_left < x_at_n_y + p.min_gutter &&
        n_right > x_at_n_y + p.r_align_tolerance &&
        (p.ragged || n_left < x_at_n_y + p.gutter_fraction * nbox.height())) {
      // In the gutter so end of line.
      if (bbox->right_tab_type() >= TT_MAYBE_ALIGNED)
        bbox->set_right_tab_type(TT_DELETED);
      *end_y = top_to_bottom ? nbox.top() : nbox.bottom();
      if (WithinTestRegion(2, x_start, start_y))
        tprintf("gutter\n");
      return nullptr;
    }
    if (!p.right_tab &&
        n_left < x_at_n_y - p.l_align_tolerance &&
        n_right > x_at_n_y - p.min_gutter &&
        (p.ragged || n_right > x_at_n_y - p.gutter_fraction * nbox.height())) {
      // In the gutter so end of line.
      if (bbox->left_tab_type() >= TT_MAYBE_ALIGNED)
        bbox->set_left_tab_type(TT_DELETED);
      *end_y = top_to_bottom ? nbox.top() : nbox.bottom();
      if (WithinTestRegion(2, x_start, start_y))
        tprintf("gutter\n");
      return nullptr;
    }
    if ((p.right_tab && neighbour->leader_on_right()) ||
        (!p.right_tab && neighbour->leader_on_left()))
      continue;  // Neighbours of leaders are not allowed to be used.
    if (n_x <= x_at_n_y + p.r_align_tolerance &&
        n_x >= x_at_n_y - p.l_align_tolerance) {
      // Aligned so keep it. If it is a marked tab save it as result,
      // otherwise keep it as backup_result to return in case of later failure.
      if (WithinTestRegion(2, x_start, start_y))
        tprintf("aligned, seeking%d, l=%d, r=%d\n",
                p.right_tab, neighbour->left_tab_type(),
                neighbour->right_tab_type());
      TabType n_type = p.right_tab ? neighbour->right_tab_type()
                                   : neighbour->left_tab_type();
      if (n_type != TT_NONE && (p.ragged || n_type != TT_MAYBE_RAGGED)) {
        if (result == nullptr) {
          result = neighbour;
        } else {
          // Keep the closest neighbour by Euclidean distance.
          // This prevents it from picking a tab blob in another column.
          const TBOX& old_box = result->bounding_box();
          int x_diff = p.right_tab ? old_box.right() : old_box.left();
          x_diff -= x_at_n_y;
          int y_diff = (old_box.top() + old_box.bottom()) / 2 - start_y;
          int old_dist = x_diff * x_diff + y_diff * y_diff;
          x_diff = n_x - x_at_n_y;
          y_diff = n_y - start_y;
          int new_dist = x_diff * x_diff + y_diff * y_diff;
          if (new_dist < old_dist)
            result = neighbour;
        }
      } else if (backup_result == nullptr) {
        if (WithinTestRegion(2, x_start, start_y))
          tprintf("Backup\n");
        backup_result = neighbour;
      } else {
        TBOX backup_box = backup_result->bounding_box();
        if ((p.right_tab && backup_box.right() < nbox.right()) ||
            (!p.right_tab && backup_box.left() > nbox.left())) {
          if (WithinTestRegion(2, x_start, start_y))
            tprintf("Better backup\n");
          backup_result = neighbour;
        }
      }
    }
  }
  return result != nullptr ? result : backup_result;
}