redraw_mark_border_cell
redraw_mark_border_cell(bctx, wx, top, wp, 0, 1, mask,
redraw_mark_border_cell(bctx, wx, bottom, wp, 1, 0,
redraw_mark_border_cell(bctx, left, wy, wp, 0, 0, mask,
redraw_mark_border_cell(bctx, right, wy, wp, 0, 0, mask,