void ImageOverlay::get_offset(size_t image_index, int32_t* x, int32_t* y) const
{
  assert(image_index>=0 && image_index<m_offsets.size());
  assert(x && y);

  *x = m_offsets[image_index].x;
  *y = m_offsets[image_index].y;
}
void ImageOverlay::get_offset(size_t image_index, int32_t* x, int32_t* y) const
{
  assert(image_index>=0 && image_index<m_offsets.size());
  assert(x && y);

  *x = m_offsets[image_index].x;
  *y = m_offsets[image_index].y;
}