[luatex] pre_output_filter: How to get the vertical list of the full page?

[Ulrike Fischer]

Am Thu, 3 May 2018 21:35:00 +1200 schrieb Henri Menke:

> How can I access the material to be pushed from within this callback?
> Box 255 (the shipout box) is nil.  The reason I am asking this is
> because I want to implement visual debugging like in ConTeXt.  Therefore
> I want to walk the main vertical list on shipout and sprinkle it with
> whatits to draw rules for boxes, glues, kerns, etc.

the lua-visual-debug package does something similar. It uses the
atbegshi package and then calls 

\AtBeginShipout
{\directlua{lvd.show_page_elements(tex.box["AtBeginShipoutBox"])}}

(it works imho with latex and plain). 


-- 
Ulrike Fischer 
http://www.troubleshooting-tex.de/