[NTG-pdftex] \pdfoptionpdfminorversion

[Hartmut Henkel]

On Mon, 21 Feb 2005, Heiko Oberdiek wrote:

> This could be solved by an internal variable that records the maximum
> version of used PDF features. Then conflicts with
> \pdfoptionpdfminorversion can be detected and an error or warning can
> be raised.

Or pdftex could track the maximum of minor version and write this value
at the _end_ of the pdftex run (currently it's written at the start, and
frozen). There is already a procedure for setting the /Length counts,
which can be mis-used, e. g. i have just tried this:

    @<Output the trailer@>;
    pdf_flush;
    write_stream_length(2,7); {experiment: set the minor version number to 2}
    print_nl("Output written on "); slow_print(output_file_name);

Then one could make a fast macro which updates the minor version at any
functionality requiring at least a certain value, about:

@d require_minor_version(#) == if minorversion < # then minorversion := #

And also the \pdfoptionpdfminorversion would just use the same macro
after clipping to max. 9. By this one could never force a minor version
value that is too low.

OTOH it's then difficult to forcibly keep pdftex at a wanted low version
number.

> Also this can be extended by a new primitive, thus that packages such
> as hyperref also can mark its code with its maximum version number of
> used PDF features.

Regards, Hartmut