+ local kbl = has_attr(p, attr_ykblshift) or 0
+ --
+ local need_hbox
+ if pwidth==fwidth then
+ -- 補正後glyph node は ht: p.height - kbl - down, dp: p.depth + min(0, kbl+down) を持つ
+ -- 設定されるべき寸法: ht: fheight - kbl, dp: fdepth + kbl
+ local ht_diff = fheight + fshift.down - getfield(p, 'height')
+ local dp_diff = fdepth + kbl - getfield(p, 'depth') - min(kbl + fshift.down, 0)
+ if ht_diff == 0 and dp_diff ==0 then -- offset only
+ set_attr(p, attr_icflag, PROCESSED)
+ setfield(p, 'xoffset', getfield(p, 'xoffset') - fshift.left)
+ setfield(p, 'yoffset', getfield(p, 'yoffset') - kbl - fshift.down)
+ return node_next(p), head, p
+ elseif ht_diff >= 0 and dp_diff >=0 then -- rule
+ local box = node_new(id_rule)
+ setfield(p, 'yoffset', getfield(p, 'yoffset') - kbl - fshift.down)
+ setfield(box, 'width', 0)
+ setfield(box, 'height', fheight - kbl)
+ setfield(box, 'depth', fdepth + kbl)
+ setfield(box, 'dir', dir)
+ set_attr(box, attr_icflag, PACKED)
+ set_attr(p, attr_icflag, PACKED)
+ head = p and node_insert_before(head, p, box)
+ or node_insert_after(head, node_tail(head), box)
+ return node_next(p), head, p, box
+ else
+ need_hbox = true
+ end
+ else
+ need_hbox = true
+ end
+
+ if need_hbox then