+ int const line_height = t->defaultHeight();
+
+ // The new absolute coordinate
+ int new_first_y = t->first_y + lines * line_height;
+
+ // Restrict to a valid value
+ new_first_y = std::min(t->height - 4 * line_height, new_first_y);
+ new_first_y = std::max(0, new_first_y);