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.
I found this issue in ruffus 2.6.3
https://github.com/bunbun/ruffus/issues/65
also discussed here
https://github.com/bunbun/ruffus/pull/67
ruffus 2.6.3 RethrownJobError don't follow the normal conventions and
so its exception causes problems when they cross process boundaries.
This change carefully examines the various forms of ruffus exception
objects that can appear in 2.6.3 and parses them more carefully. It
also removes any direct posting of the exception to the logger because
this triggers another serializing of the exception object, mutating it
further.
/ImageMask means the the image is a stencil mask for a grayscale or
color image. From issue #63 a user has a PDF apparently with only a
stencil mask and no other images. According to PDF spec you're supposed
to use masks to help draw other images rather than draw masks
explicitly, although drawing masks is not forbidden.
In the event that the image mask is higher resolution than the input
image, the composite image should be drawn at the highest DPI to a
ccurately capture the effect of the mask. It looks like the right to
do is take masks into account rather than ignore them (a holdover
from earlier, less robust versions), or don't treat it different.
James R. Barlow