def run_rig_args(args, **kwargs):
# Remove the two arguments that tell ghostscript to create a PDF/A
# Does not remove the Postscript definition file - not necessary
# to cause PDF/A creation failure
new_args = [
arg for arg in args
if not arg.startswith('-dPDFA') and not arg.endswith('.ps')
]
proc = run_polling_stderr(new_args, **kwargs)
return proc
def run_append_stderr(*args, **kwargs):
proc = run_polling_stderr(*args, **kwargs)
proc.stderr += '\n' + elision_warning + '\n'
return proc
def generate_pdfa(
pdf_pages,
output_file: os.PathLike,
*,
compression: str,
pdf_version: str = '1.5',
pdfa_part: str = '2',
progressbar_class=None,
):
# Ghostscript's compression is all or nothing. We can either force all images
# to JPEG, force all to Flate/PNG, or let it decide how to encode the images.
# In most case it's best to let it decide.
compression_args = []
if compression == 'jpeg':
compression_args = [
"-dAutoFilterColorImages=false",
"-dColorImageFilter=/DCTEncode",
"-dAutoFilterGrayImages=false",
"-dGrayImageFilter=/DCTEncode",
]
elif compression == 'lossless':
compression_args = [
"-dAutoFilterColorImages=false",
"-dColorImageFilter=/FlateEncode",
"-dAutoFilterGrayImages=false",
"-dGrayImageFilter=/FlateEncode",
]
else:
compression_args = [
"-dAutoFilterColorImages=true",
"-dAutoFilterGrayImages=true",
]
strategy = 'LeaveColorUnchanged'
# Older versions of Ghostscript expect a leading slash in
# sColorConversionStrategy, newer ones should not have it. See Ghostscript
# git commit fe1c025d.
strategy = ('/' + strategy) if version() < '9.19' else strategy
if version() == '9.23':
# 9.23: added JPEG passthrough as a new feature, but with a bug that
# incorrectly formats some images. Fixed as of 9.24. So we disable this
# feature for 9.23.
# https://bugs.ghostscript.com/show_bug.cgi?id=699216
compression_args.append('-dPassThroughJPEGImages=false')
# nb no need to specify ProcessColorModel when ColorConversionStrategy
# is set; see:
# https://bugs.ghostscript.com/show_bug.cgi?id=699392
args_gs = ([
GS,
"-dBATCH",
"-dNOPAUSE",
"-dSAFER",
"-dCompatibilityLevel=" + str(pdf_version),
"-sDEVICE=pdfwrite",
"-dAutoRotatePages=/None",
"-sColorConversionStrategy=" + strategy,
] + compression_args + [
"-dJPEGQ=95",
"-dPDFA=" + pdfa_part,
"-dPDFACompatibilityPolicy=1",
"-o",
"-",
"-sstdout=%stderr",
])
args_gs.extend(fspath(s) for s in pdf_pages) # Stringify Path objs
try:
with Path(output_file).open('wb') as output:
p = run_polling_stderr(
args_gs,
stdout=output,
stderr=PIPE,
check=True,
text=True,
encoding='utf-8',
errors='replace',
callback=GhostscriptFollower(progressbar_class),
)
except CalledProcessError as e:
# Ghostscript does not change return code when it fails to create
# PDF/A - check PDF/A status elsewhere
log.error(e.stderr)
raise SubprocessOutputError(
'Ghostscript PDF/A rendering failed') from e
else:
stderr = p.stderr
# If there is an error we log the whole stderr, except for filtering
# duplicates.
if _gs_error_reported(stderr):
last_part = None
repcount = 0
for part in stderr.split('****'):
if part != last_part:
if repcount > 1:
log.error(
f"(previous error message repeated {repcount} times)"
)
repcount = 0
log.error(part)
else:
repcount += 1
last_part = part