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.
At recommendation of Artifex people, don’t use the filename pdfa_def.ps
because if given without a full path Ghostscript will prioritize
searching its own resources over the current directory, and will pick up
the example file pdfa_def.ps instead. We used the full path anyway,
but this is a prudent defensive change to avoid odd Ghostscript behavior.
Unfortunately because of this issue
https://github.com/docker/hub-feedback/issues/292
Docker Hub effectively automatically changes directory to the location
of Dockerfile, meaning needed files are not in the right places, so
this has to be reverted.
This reverts commit 65c9a07dde.
[ci skip]
Unfortunately because of this issue
https://github.com/docker/hub-feedback/issues/292
Docker Hub effectively automatically changes directory to the location
of Dockerfile, meaning needed files are not in the right places, so
this has to be reverted.
Installing Tess4 PPA over Tess3 proved too much pain, so sever the link
between this and the jbarlow83/ocrmypdf image, starting each from
scratch. Also the complete set of language packs proves too much - the
build seems likely to fail when trying to install so many.
Debian now has a few disadvantages:
-there is no convenient PPA for Debian tesseract 4.0, but there is for
Ubuntu
-Ubuntu sets locale to UTF-8 automatically removing the need to do this
All three ocrmypdf docker images are now based on a common Ubuntu
16.10 image, derived from the one used to build ocrmypdf-tess4.
-polyglot now differs from -tess4 only by opting into the tess4 PPA.
Both Ubuntu 16.10 and Debian stretch use tesseract 3.04.01 now making
the sharp.ttf patch unnecessary. /etc/apt/sources has been unused for a
while now both have newer Ghostscripts.
At least on macOS with my quadcore performance improves with two
tesseracts in parallel (20% gain). Hard to say how this will affect
Linux, but stepping up to 2 jobs seems justifiable.
James R. Barlow