--- Robert Dodier <robert_dodier@yahoo.com> wrote:
> C Y <smustudent1@yahoo.com> wrote:
> > I imagine, since we are creating the pdf document fairly directly,
> > the relevant plotting output can be included as part of a larger
> > file - just have output modes for "part of document"
> > and "standalone pdf".
> > Of course, maybe it would be more complicated, but I don't quite
> > see why.
>
> AFAIK it is not straightforward to glom pieces of PDF
> files together to make a whole PDF file.
Right. I didn't mean grabbing a pdf and wedging it into another pdf, I
was thinking more along the lines of regenerating all pdf content when
the command "print notebook" was used. We can retain the points
generated by the plot command so we don't have to do a complicated plot
calculation twice, and simply use them as part of the data in creating
the larger page by page pdf.
> PDF is a binary format (even if all bytes are printable 7 bit ascii)
> -- a PDF file comprises a number of objects and there is a
> lookup table at the end which tells the byte offset of
> each object within the file. So to combine PDF's it would
> probably be necessary to parse the file to extract objects,
> combine the objects, and rebuild the offset table. Or,
> maintain each object separately and only output the objects
> plus their offset table when there are no more objects to add.
I don't quite see why we would want to do anything except either a)
standalone pdf files with plots, in which case it's not an issue or b)
a nice page/poster/etc. format of the entire document, and all
necessary pdf can be created when making the document from original
source date. Instead of retaining the pdf of the plot, we just create
a pdf using the data as part of the larger document. We probably don't
want to generate pdf anyway until the user asks for a file output,
unless I misunderstand the proposed uses for cl-pdf.
> PDF has several capabilities over and above PS, such as
> internal links, although I don't know that all such
> capabilities are useful in a technical context. However,
> a PDF viewer seems to be more common on MS Windows systems
> than a PS viewer, and that may be the strongest argument
> in favor of PDF for Maxima.
That is essentially THE argument. I like the ability to select text
from a pdf using acrobat/xpdf, but I don't imagine that will prove
particularly useful in a mathematical context except perhaps to copy a
1D input expression. However, IMO the ubiquity and general usefulness
of pdf is enough to validate it, other concerns aside.
CY
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