Method SplitAt

deps/tesseract/textord/colpartition.cpp:831–866

Split this partition at the given x coordinate, returning the right half and keeping the left half in this.

// Split this partition at the given x coordinate, returning the right
// half and keeping the left half in this.
ColPartition* ColPartition::SplitAt(int split_x) {
  if (split_x <= bounding_box_.left() || split_x >= bounding_box_.right())
    return NULL;  // There will be no change.
  ColPartition* split_part = ShallowCopy();
  split_part->set_owns_blobs(owns_blobs());
  BLOBNBOX_C_IT it(&boxes_);
  for (it.mark_cycle_pt(); !it.cycled_list(); it.forward()) {
    BLOBNBOX* bbox = it.data();
    ColPartition* prev_owner = bbox->owner();
    ASSERT_HOST(!owns_blobs() || prev_owner == this || prev_owner == NULL);
    const TBOX& box = bbox->bounding_box();
    if (box.left() >= split_x) {
      split_part->AddBox(it.extract());
      if (owns_blobs() && prev_owner != NULL)
        bbox->set_owner(split_part);
    }
  }
  if (it.empty()) {
    // Possible if split-x passes through the first blob.
    it.add_list_after(&split_part->boxes_);
  }
  ASSERT_HOST(!it.empty());
  if (split_part->IsEmpty()) {
    // Split part ended up with nothing. Possible if split_x passes
    // through the last blob.
    delete split_part;
    return NULL;
  }
  right_key_tab_ = false;
  split_part->left_key_tab_ = false;
  right_margin_ = split_x;
  split_part->left_margin_ = split_x;
  ComputeLimits();
  split_part->ComputeLimits();
  return split_part;
}

// Recalculates all the coordinate limits of the partition.
void ColPartition::ComputeLimits() {