[pdftex] pdfsavepos

[Andre Wobst]

Hi,

lately I became interested in a nice feature of pdfTeX, namely
\pdfsavepos, \pdflastxpos, and \pdflastypos. Unfortunately, while I
was quite successfull in the stuff I really wanted to do, I realized
now, that I can use this nice feature of pdfTeX in pdf-mode only. But,
blame on me, I'm restricted to a dvi file creation. Now my question
is, if there is a deeper reason for the restriction of pdfTeX to make
this feature available in pdf-mode only. I've taken a look into the
pdftex source already and found the check named "check_pdfoutput"
preformed when using pdfsavepos. (You can savely access the registers
pdflastxpos and pdflastypos, but this isn't usefull without
pdfsavepos). I've tried to just remove that check to see what happens
then, but I ended up with the TeX message: "! I can't go on meeting
you like this." (which is not what I want ;-)).

Right now it would be interesting whether it makes any sense to take a
deeper look into the pdfTeX source in order to make this feature
available in dvi-mode as well. Right now I just didn't got deeply
enough into the source in order to understand how this feature is
implemented. Maybe somebody could advice me if it should be possible
at all to implement this feature in dvi-mode based on the pdftex code.


André

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