-%--------------------------------------
-% following codes are almost copied from
-% pxatbegshi.sty 2019/09/07 v0.5 (in platex-tools bundle, by H. Yamashita).
+% concept: execute all hooks inside yoko direction \vbox
+
+\ifltj@ltshipout@avail
+%<*ltshipout>-----------------------------------
+%
+\RequirePackage{expl3}
+\ExplSyntaxOn\makeatletter
+\box_new:N \l__platex_shipout_dummy_box
+\pretocmd {\__shipout_execute_cont:}
+ {\tex_setbox:D \l__platex_shipout_dummy_box \tex_vbox:D \c_group_begin_token \yoko } {} {}
+\apptocmd {\__shipout_execute_cont:} {\c_group_end_token} {} {}
+\ExplSyntaxOff
+%</ltshipout>-----------------------------------
+
+\else
+\AtBeginShipoutInit
+%<*atbegshi>-------------------------------------
+% patching atbegshi.sty
+%%% following codes are almost copied from
+%%% pxatbegshi.sty 2019/09/07 v0.5 (in platex-tools bundle, by H. Yamashita).