On 3/19/2018 11:20 AM, Alexander Grahn wrote:
Dear all,
it seems that I discovered a bug in connection with nested Form XObjects
(pdftex built-in \pdfxform) that occurs in pdfTeX as well as in LuaTeX.
The \pdfxform built-in provides the optional `resources {<resources>}'
argument, as in
\pdfxform resources {<resources>} <box>
, in order to allow the user to insert additional entries in the /Resources
dictionary of the Form XObject to be produced from box register <box>.
This works as advertised for ordinary box content (1st \pdfxform in the code
below), but as soon as another Form XObject is referenced inside <box>, the
`resources {...}' argument is ignored and user-provided <resources> are missing
in the generated PDF code (2nd \pdfxform).
Here is a minimal example for pdfTeX and LuaTeX for demonstration. The PDF
object numbers mentioned in the comments are different in the PDF output from
LuaTeX.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Bug: When nesting Form XObject reference in <box>,
% \pdfxform resources {<resources>} <box>
% --> missing user-provided <resources>
\input luatex85.sty
\pdfcompresslevel=0
\pdfobjcompresslevel=0
\setbox0=\hbox{World}
\edef\wrldwd{\the\wd0}
\pdfxform
attr {}
resources {/Properties <</Key1 (Val1)>>} % OK
0
%nesting Form XObject reference
\setbox0=\hbox{Hello \hbox to \wrldwd {\pdfrefxform\pdflastxform\hss}!}
\pdfxform
attr {}
% /Properties <<...>> missing in /Resources dict (object `8 0'), ref'ed in
resources {/Properties <</Key2 (Val2)>>}% Form XObject (object `2 0')
0
\pdfrefxform\pdflastxform
\bye
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
there is no nesting stack kept there ...
\immediate\pdfxform ...
works ok
Hans
-----------------------------------------------------------------
Hans Hagen | PRAGMA ADE
Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------
