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).
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.
... preferring to composite with a white background instead of removing
the alpha channel. This seems to more reliably produce high-quality
conversions (easier to read, fewer conversion artifacts) than either the
prior or other previous approaches.
Added weak tests for a couple of hard-to-test visual debugging methods
in display.py.
Also marked an exception-handling block in pdf.py as `pragma: nocover`
because we don't yet have a PDF to test it with, but the logic there is
simple and straightforward.
Per discussion at https://github.com/jsvine/pdfplumber/discussions/346
and input from @ramcdona, this commit changes pdfplumber's behavior
regarding floating point numbers. Specifically, it removes all
conversion of floats to Decimal objects. This brings several advantages:
- Increased precision (where applicable)
- Decreased code complexity
- Increased performance (~10% speedup on test suite)
- Increased fidelity to `pdfminer.six` output
These seem to outweigh the disadvantages:
- Some tests break (but have been easily fixed) due to increased
precision and/or floating point arithmetic artifacts
- Some users' scripts may also break, if they depend on strict equality
testing, though these *should* also be easily fixable
Because some form of automatic rounding may still be desirable for the
pdfplumber CLI utility, the conversion methods (.to_csv, .to_json) have
been adjusted to accept a `precision` argument.
Jeremy Singer-Vine