Function AddBaselineCoordsTohOCR

deps/tesseract/api/baseapi.cpp:1320–1357

* Fits a line to the baseline at the given level, and appends its coefficients * to the hOCR string. * NOTE: The hOCR spec is unclear on how to specify baseline coefficients for * rotated textlines. For this reason, on textlines that are not upright, this * method currently only inserts a 'textangle' property to indicate the rotation * direction and does not add any baseline information to th

 * direction and does not add any baseline information to the hocr string.
 */
static void AddBaselineCoordsTohOCR(const PageIterator *it,
                                    PageIteratorLevel level,
                                    STRING* hocr_str) {
  tesseract::Orientation orientation = GetBlockTextOrientation(it);
  if (orientation != ORIENTATION_PAGE_UP) {
    hocr_str->add_str_int("; textangle ", 360 - orientation * 90);
    return;
  }

  int left, top, right, bottom;
  it->BoundingBox(level, &left, &top, &right, &bottom);

  // Try to get the baseline coordinates at this level.
  int x1, y1, x2, y2;
  if (!it->Baseline(level, &x1, &y1, &x2, &y2))
    return;
  // Following the description of this field of the hOCR spec, we convert the
  // baseline coordinates so that "the bottom left of the bounding box is the
  // origin".
  x1 -= left;
  x2 -= left;
  y1 -= bottom;
  y2 -= bottom;

  // Now fit a line through the points so we can extract coefficients for the
  // equation:  y = p1 x + p0
  double p1 = 0;
  double p0 = 0;
  if (x1 == x2) {
    // Problem computing the polynomial coefficients.
    return;
  }
  p1 = (y2 - y1) / static_cast<double>(x2 - x1);
  p0 = y1 - static_cast<double>(p1 * x1);

  hocr_str->add_str_double("; baseline ", round(p1 * 1000.0) / 1000.0);
  hocr_str->add_str_double(" ", round(p0 * 1000.0) / 1000.0);
}

static void AddIdTohOCR(STRING* hocr_str, const std::string base, int num1,
                        int num2) {