unsigned line_height = static_cast<unsigned>((font->get_ascent()-font->get_descent())*font_size);
unsigned line_spacing = static_cast<unsigned>(font_size*6/5);
unsigned height = line_height+(lines.size()-1)*line_spacing;
unsigned line_height = static_cast<unsigned>((font->get_ascent()-font->get_descent())*font_size);
unsigned line_spacing = static_cast<unsigned>(font_size*6/5);
unsigned height = line_height+(lines.size()-1)*line_spacing;