[texhax] [pdftex] image XObjects in pdfTeX or XeTeX PDF output?

[Paul Isambert]

Selon Alexander Grahn <A.Grahn at fzd.de>:

> On Mon, Nov 22, 2010 at 07:53:44AM -0500, William Adams wrote:
> >On Nov 19, 2010, at 3:30 PM, Ross Moore wrote:
> >
> >(re: an image included multiple times being included but once and thereafter
> referred to)
> >
> >> PdfTeX does this automatically for you.
> >
> >So does XeTeX.
>
> This may work with inclusion of external graphics from files, with TeX
> boxes it doesn't:
>
> \setbox0=\hbox{Hello World!}\copy0\copy0\copy0
>
> does not create a Form XObject to be inserted on every \copy0, at least
> at my end.

No, you need to declare the XObject as such:

\setbox0=\hbox{Hello world.}
\pdfxform0
\pdfrefxform\pdflastxform

Note that box 0 is empty after the second line. So pdfTeX does that
automatically for you... once you know the right command :)

Best,
Paul