# [Dev-luatex] Possible issue with input from external libraries (page break problem?)

Hans Hagen pragma at wxs.nl
Wed Apr 14 21:46:46 CEST 2010

On 14-4-2010 8:58, Hartmut Henkel wrote:

> but it is so since ancient pdftex times (and i have also stumbled over
> it, and since then i'm wrapping \pdfrefximage in a \hbox, as you
> suggest). The \pdfrefximage doesn't do any h or v mode change, it's
> neutral. And i guess one should keep it like this to avoid
> incompatibilities.

indeed, and i can imagine the why, but i can also imagine that in luatex
we wrap it in an hbox as we're not bound to compatibility in luatex; it
can even be conditional: if in hmode then no wrapping, else wrap it in
an hbox; alternatively when issues in vmode we couldl set a flag that
indicates that in the backend the image is lapped up (tlap) so that the
effective height in the page stream is zero (actually that would be the
cleanest solution as something similar happens with annotations)

a comparison with specials is not right as specials are not looked at
this way

for pdftex i can imagine that a warning is issued, something:

"injecting whatsit node with dimensions into a vertical list; this
confuses the page builder"

or something like that

actually, it's a problem with all whatsits that cary dimensions so when
we're further along the luatex road we can consider a special kind of
hlist subtype for this kind of things

Hans

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