Method GetTextDirection

deps/tesseract/api/baseapi.cpp:2134–2166

TODO(rays) Obsolete this function and replace with a more aptly named function that returns image coordinates rather than tesseract coordinates.

// TODO(rays) Obsolete this function and replace with a more aptly named
// function that returns image coordinates rather than tesseract coordinates.
bool TessBaseAPI::GetTextDirection(int* out_offset, float* out_slope) {
  PageIterator* it = AnalyseLayout();
  if (it == NULL) {
    return false;
  }
  int x1, x2, y1, y2;
  it->Baseline(RIL_TEXTLINE, &x1, &y1, &x2, &y2);
  // Calculate offset and slope (NOTE: Kind of ugly)
  if (x2 <= x1) x2 = x1 + 1;
  // Convert the point pair to slope/offset of the baseline (in image coords.)
  *out_slope = static_cast<float>(y2 - y1) / (x2 - x1);
  *out_offset = static_cast<int>(y1 - *out_slope * x1);
  // Get the y-coord of the baseline at the left and right edges of the
  // textline's bounding box.
  int left, top, right, bottom;
  if (!it->BoundingBox(RIL_TEXTLINE, &left, &top, &right, &bottom)) {
    delete it;
    return false;
  }
  int left_y = IntCastRounded(*out_slope * left + *out_offset);
  int right_y = IntCastRounded(*out_slope * right + *out_offset);
  // Shift the baseline down so it passes through the nearest bottom-corner
  // of the textline's bounding box. This is the difference between the y
  // at the lowest (max) edge of the box and the actual box bottom.
  *out_offset += bottom - MAX(left_y, right_y);
  // Switch back to bottom-up tesseract coordinates. Requires negation of
  // the slope and height - offset for the offset.
  *out_slope = -*out_slope;
  *out_offset = rect_height_ - *out_offset;
  delete it;

  return true;
}

/** Sets Dict::letter_is_okay_ function to point to the given function. */
void TessBaseAPI::SetDictFunc(DictFunc f) {