Forgot to update tesseract spoofers to account for change in tesseract
parameters. Also the change to outputting multiple files in the collate
steps affected how ruffus passes information into downstream consumers
of those files.
If tess4 renderer needed to skip OCR on a page it would end up
duplicating the page contents onto the new page, rather than creating
a blank OCR layer and placing it on the output page. This created
duplicated content in output files.
Ghostscript 9.21 does not seem to accept Unicode above U+FFFF. Previous
versions did, but it now exits with a rangecheck error (-15).
Reject on the command line for now. Complete fix would also need to
check input PDF’s metadata.
Because ruffus doesn’t handle exceptions well I tended to call sys.exit
to make sure we got out of dodge when needed. However, sys.exit is not
ideal for the Python API this is moving towards, so this introduces
proper exceptions for the various cases that retain suggested error
codes. Only __main__.py should call sys.exit now, everyone else has to
throw an exception.
For now the worker raising a fatal exception is logging messages rather
than passing an exception object with the fatal error message, mainly
because ruffus doesn’t properly marshall the exception object so we
just check “what is the name of the exception class that caused ruffus
to thrown an RethrownJobError”?
Also fixed along the way was the wrong return code being shown for
encrypted PDF checking, and incorrect use of str.find (e.output.find)
in boolean logic (str.find returns -1 on failure to find, which is True).
Turns out this occurred in any case where pdf-renderer hocr was used
and a tesseract timeout or error occurred. We created a replacement
page based on the unrotated page dimensions instead of the input image’s
dimensions.
For sanity's sake, deal with tesseract streams in binary without
transcoding (via universal_newlines, etc.). The only differences are
printing messages regarding spoofing.
Also hash the source file so that changes to the cache mechanism
invalidate old cache automatically. That is probably too aggressive,
but simple and safer than the previous approach.
James R. Barlow