QPDF for PDF transformations

Neat PDF transformation utility.

PDF site

I think Planet PDF has essentially everything you want to know about the PDF format.  Here's a sample: PDF stamping.

PDFminer

PDFminer is a Python library for extracting information from PDFs.

iText PDF API

I'd forgotten about this, but it's a pretty slick-looking Java/C# (?) library for working with PDF. Oughta go into the domain.

PDFMiner

Python library for reading PDFs.

PDFkit

PDF generation for node.js. Hmm.

PDF internals

CAM::PDF is a pretty nice module, but as usual I've been wanting something different. So I'm back to the PDF domain, this time with a tag "pdf-internals". The internals tag is kind of different from anything I've done before, in that during payload build it goes out, finds the file specified, and then builds macro structure representing its contents.

The result, when self-described, is a readable overview of the contents of the PDF. And since the nodal structure still hooks back into the CAM::PDF::Node structure (well, it doesn't right at the moment, but you know what I mean) it ought to be relatively simple to modify and write the file back out. I haven't explored that; right now, I'm much more interested in introspection.

Reading takes place in multiple phases. First, we build the list of objects and add PDF::Declarative::InternalValue objects (which are nodes) that take whatever tag describes the type of internal value (dictionary, array, hexstring, stream, and so on). Names are the dictionary names from the PDF data structure, and labels are generally values for scalars, unused for other data types.

I'm still working on interpreting page content streams, but the idea is to locate the text strings and group them into paragraphs according to their mutual proximity and fonts. To do this, I'm going to have to develop a simple PDF command interpreter, so things are going a little slowly. But I really think it's doable, and good handling of PDFs is essential for all kinds of tasks.

I ran across a nice technical paper on PDF structure here (dated 1999, but still a great overview).

Update: The NitroPDF package does what I need to do. Of course, it's not a scripting solution, but at least it will get me what I need today, plus provide a benchmark for performance. It really munges font spacing in order to get a Word document that corresponds closely to the PDF (otherwise your text will overlap any graphical decoration). I hate that; it makes it impossible to work with TagEditor. Of course, I have my unmunge.dpl script, but still: I need something more scriptable and flexible in the long run.

PDF::Declarative

The PDF::Declarative class being a wrapper around PDF::API2 (at least currently), I went looking for good examples, and found a fantastic tutorial by Rick Measham. It took some work and some extra functionality added to Class::Declarative (which was of course the point), but I can now generate a PDF equivalent to his tutorial example using PDF::Declarative. This is the code, somewhat abridged, because it contains the text for the PDF:

use Class::Declarative qw(PDF::Declarative);

pdf (displaytitle, encoding=latin1) "mynewpdf.pdf"
 author    "Michael Roberts"
 title     "PDF::Declarative Example 1"
 subject   "Building PDFs with explicitly placed elements"
 keywords  "Declarative PDF generation"
 mediabox  "105mm x 148mm"
 #bleedbox "5mm, 5mm, 100mm, 143 mm"
 cropbox   "7.5mm 7.5mm 97.5 mm 140.5mm"
 #artbox   "10mm, 10mm, 95mm, 138mm"

 page
    graphic blue_box
       fill (darkblue)
       rect "5mm, 125mm, 95mm, 18mm"
    graphic red_line
       stroke (red)
       move "5mm, 125mm"
       line "100mm, 125mm"
    text heading (flow=no, x=95mm, y=131mm, align=right, color=white, font=helvetica, bold, fontsize=18pt)
       Using PDF::Declarative
    graphic background
       stroke (lightgrey)
       circle "20mm, 45mm, 45mm"
       circle "18mm, 48mm, 43mm"
       circle "19mm, 40mm, 46mm"
    box left_column (border) "10mm, 121mm, 41mm, 111mm"
       text (lead=7pt, parspace=0, align=justify, color=black, font=times, fontsize=6)
          Perci ent ulluptat vel eum zzriure feuguero core consenis adignim...

       text (align=center, font=helvetica, bold, fontsize=6pt, color=blue)
          Enim eugiamc ommodolor sendre feum zzrit at. Ut prat. Ut lum quisi.
     
       text (align=right, font=times, color=black, fontsize=6pt)
          It augait ate magniametum irit, venim doloreet augiamet...
     
    graphic
       image "54mm, 66mm, 41mm, 55mm"
          jpeg "Portrait.jpg"

    box right_column (border, dash=2 2 1 2, color=blue) "54mm, 64mm, 41mm, 54mm"
       text (lead=7pt, parspace=0pt, align=justify, indent=5pt, fontsize=6pt, bullet=B7)
          Orpero do odipit ercilis ad er augait ing ex elit autatio....

Well, one correction: I haven't implemented bullet points yet.

Again: the above is a complete Perl program, and it generates a valid PDF file with justified text in columnar boxes. With a few extensions to the existing code, I think it's going to be just about time to release it into the wild, my first semantic module to qualify.

Current calendar time invested: 11 days. I think about a month would be necessary to do PDFs right - probably far more to do them right, but "good enough" in a month is pretty fast work. Fast enough I haven't lost interest before finishing something useful.

PDF::Declarative

Man, I started PDF::Declarative two days ago, and nearly have something that can do the PDFs I want. Turns out text layout is hard - who knew? But building declarative wrappers for new domains is relatively easy, given good example code.

So I'm really quite happy about the declarative framework; it's making me a faster, better, more productive programmer, and that's all I really need it to do.

An interesting semantic domain at some point would be the generation of new semantic domains... Speeding up the process of speeding up the process should, um, speed up the process.