More thorough testing showed that Acrobat do not presume that images
fill the page if the CTM is unspecified, as tests/resources/masks.pdf
seems to want. Instead they treat it literally and draw the image
as 1x1 PDF units or 1/72" square in the bottom left corner of the page.
Seems like the best thing to do is ignore any such images for the purpose
of DPI calculation. masks.pdf still works out okay because it has
other images.
For more robustness we could consider invalidating any DPI above some
limit, or warning the user about these microdot thumbnails.
Executing a package with python -m packagename will check for
__main__.py inside the package. In other words main.py should have
always been named __main__.py.
In the unlikely event that someone depends on "import ocrmypdf.main"
being meaningful, main.py continues to exist and replicates the
behavior of __main__. (It's unlikely because import ocrmypdf.main does
unpythonic ruffus-related things at things import time, essentially
configuring itself to work with sys.argv. To fix another day.)
This should solve the problem of Debian needing to run test suites
before installation and afterwards for continuous integration without
having to patch either file, as python -m ocrmypdf will follow import
order. That is, if the current directory contains "ocrmypdf/" (e.g.
staging a new version) then that will be tested, else sys.path will
be checked.
The recent commit to accept files from stdin broken the feature of
returning the input filename on an error, returning the temp filename
instead, which is confusing.
I tried "qpdf merge + PyPDF2 metadata patching" first. The problem is
that PyPDF2 produces a 1.3 by default and generally I have less
confidence it.
New approach is to stuff the Document Info metadata in the first page
with PyPdf2, cross fingers and use qpdf to merge. It's not quite as
clean and might harm the first page, but it's better than shipping
files produced by PyPDF2.
Tests mostly passing. For the moment this is the new default.
Although PyPDF2 produces a PDF-1.3 which will be wrong for some contents
and possible should be repaired with qpdf. Again.
Looks like it could work better to merge PyPDF2 and fix everything
with qpdf.
This test is exercised by page 4 of multipage.pdf. If all images are
JPEGs, and one of deskew/clean removes DPI information, make sure that
we can get the right information back and that the DPI stays square.
Some called functions are particular about the data format of DPI and
don't like to deal with the Decimal() returned by PyPDF2. Convert to
float and int where needed.
Issue #79.
User submitted PDF with ICC profile attached to the monochrome image
in the input file, which is not common but useful for PDFs that want to
define how light the paper is or how dark the black is. The code was
written to assume unusual images are full color unless it can prove
otherwise. Handle this simple case. Other ICC cases should be tested.
Issue #73. The order of operations happens to not matter for scaling
but does matter for translation. We only need scaling to find the DPI,
so the error was not noticed. Mainly useful to other uses of this
library.
James R. Barlow