l3backend: adding new DVI specials?

[Zdenek Wagner]

Hi,

many years ago (when using emTeX in OS/2) I wrote a package which can
create multilie hyperlinks by dvips + distiller (or ghostscript). It
is here:
http://icebearsoft.euweb.cz/tex/#pdf
Unfortunately it is undocumented, only one article was written about
it in Czech. The idea is that the LaTeX macro inserts a PS code at the
beginning and at the end. These PS macros measure the area. If it is
in a single line, just one hyperlink is created. If there is a line
break, two hyperlinks with the same target are created. Maybe it can
help you.

Zdeněk Wagner
http://ttsm.icpf.cas.cz/team/wagner.shtml
http://icebearsoft.euweb.cz

čt 13. 2. 2020 v 8:54 odesílatel Joseph Wright
<joseph.wright at morningstar2.co.uk> napsal:
>
> On 13/02/2020 04:26, Norbert Preining wrote:
> > Hi all,
> >
> > the recent update of the l3 packages changed something with the DVI
> > specials. pyxplot suddently gives warnings about unhandled DVI specials:
> >       header=l3backend-dvips.pro
> > is this a known change and to be expected?
> >
> > Best
> >
> > Norbert
>
> Hello Norbert,
>
> A while ago now we added some code to l3backend to start to address 'out
> of the box' PDF feature handling. That's for stuff like hyperlinks,
> color, etc. In DVI mode, one needs stuff adding to the PostScript
> header. (At present not all of this is 'live', in particular link breaking.)
>
> Initially, we simply added everything as \special lines directly
> containing the PostScript, but that leads to warnings with dvipdfmx if
> the right backend isn't selected. It also meant there was lots of
> material in the \showbox output. Moving it to a .pro file meant that
> inclusion used only one line
>
>      \special{header=l3backend-dvips.pro}
>
> and this line is simply ignored by dvipdfmx. We realised that other
> systems might not know this one line, but felt that it was hopefully
> possible that a similar '"skip header=" lines' might be added to any
> cases. The one we had in mind was dvisvgm: I'm not familiar with pyxplot.
>
> Joseph
>