Thanks to PR from @jeremybmerrill, who writes:
> This form-parsing example handles form fields recursively contained within other form fields, removes the incorrect-assumption that field-names are unique and includes the alternate field name in output (which is often a very useful guide to what's in a field).
> the prior form-parsing example used the field-name ("T" entry) as the key in the form_data dict, implicitly assuming that the field name is globally unique within a document. That's not a correct assumption; nested field names are often simply a numeric index like 1 or 0. The prior example also entirely ignored the TU entry alternate field name.
These are related changes, since the previous approach of using
`PDF.stream.name` to distinguish between on-path and filelike-object PDFs
doesn't work for zipped files (and possibly other filelike-objects that
have a `name` property).
Note: this removes the fragile-looking type manipulation in intersects_bbox as
making it work with iterables is very ugly and I am not convinced of its
usefulness
This commit adds convenience methods to repair PDFs on the fly and/or to
write repaired PDFs to disk.
Currently, this does so via Ghostscript using the method we've asked
many users to try by following the instructions at
https://superuser.com/questions/278562/how-can-i-fix-repair-a-corrupted-pdf-file
Now, hopefully, this saves folks a few steps.
This commit swaps out Wand (and its non-Python dependencies ImageMagick
and Ghostscript) for pypdfium2 for PageImage rendering. This has some
advantages:
- Less finicky: Wand often caused users problems, due to "MagickWand
shared library not found" and "PolicyError: not authorized `PDF'"
issues. By contrast, pypdfium2 seems (at least at first) to more
self-contained and not require any system-tweaking.
- Faster: pypdfium2 appears to render images more quickly than Wand (see
@cmdlineuser's tests in #899)
- More flexible: pypdfium2 appears to generate images with greater color
depth; by default, pdfplumber quantizes those images so that they
save/display compactly (in fact, with smaller file sizes than the
previous code), this commit also adds parameters to retain all/more of
the original, more detailed colors.
Thanks to @cmdlineuser in #899 for the suggestion.
Andy Friedman