[pdftex] Another request for an enhancement to pdf(La)TeX
jjq at galcit.caltech.edu
Tue Oct 26 12:40:07 CEST 2010
On Tue, 26 Oct 2010, André Wobst wrote:
> Dear all,
> I'm reading the recent discussion with great interest. I have another issue, which happens to be on my TODO list for years, but I never managed to get back to it. The request is related to compiling large PDF files on remote systems. I'll go in some details here; I'm not sure whether to file a bug report instead. If you are curious, just read on.
> At the moment it is not possible to stream the output of pdf(La)TeX while it is generated. This is not a problem of having pdf(La)TeX writing its output to a file with a certain name, as you could easily set up a named pipe for that. I already tried this, but the problem is seeking in the PDF being generated, namely when inserting certain streams in the PDF output. The length of the stream is inserted after the stream has been written by leaving some space first and than seeking back to this position once the stream has been written and its size is known. It is in the pdf_begin_stream and pdf_end_stream functions in texk/web2c/pdftexdir/pdftex.web. (It might be that there are other positions as well, but I'm not aware of any other point where such seeks occur.)
> Instead of seeking back to fill in the size of the stream, one could insert a reference to another PDF object there and fill the length of the stream in that additional PDF object once the stream has been finished. Unfortunately I'm not able to try and patch pdftex myself as I don't know how to write in the web language, setup a build infrastructure etc.
> Do I get any support for this feature request?
I can see where you are coming from with your request. For large PDF
files, however, one would generally like to take advantage of compressed
object streams. Now I haven't had the chance to delve into the source
to see how said streams are generated by pdftex, but I can imagine
how they complicate the general solution to your request.
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