yujunjun/OCRmyPDF
1
0
Fork 0
mirror of https://github.com/ocrmypdf/OCRmyPDF.git synced 2025-12-28 07:30:04 +00:00
Code Issues Packages Projects Releases Wiki Activity

Convert monochrome images to JBIG2

Browse Source 
Awkwardly using fitz and pikepdf, transcode monochrome to CCITT.
This requires _OCRMYPDF_NO_FITZ=1.

00000x.opt.pdf can be checked for JBIG2 to confirm, but this file is
not passed to the output since it's not all wired up yet.
This commit is contained in:
James R. Barlow 2018-04-01 14:14:34 -07:00
parent a95ffcdc46
commit d8ac6e28ab
1 changed files with 26 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
src/ocrmypdf/pipeline.py
View File

@ -808,10 +808,16 @@ def jbig2_10to1(
output_file,
log,
context):
assert fitz
import fitz
import pikepdf
options = context.get_options()
infiles = list(flatten_groups(infiles))
# pdf = pikepdf.Pdf.new()
# for infile in infiles:
# subdoc = pikepdf.Pdf.open(infile)
# pdf.pages.extend(subdoc.pages)
doc = fitz.open()
for infile in infiles:
subdoc = fitz.open(infile)
@ -831,7 +837,6 @@ def jbig2_10to1(
pix.writePNG(str(root / '{:08d}.png'.format(xref)), savealpha=False)
changed_xrefs.append(xref)
doc.save(output_file + '_tmp.pdf')
doc = fitz.open(output_file + '_tmp.pdf')
from subprocess import run, PIPE
args = ['jbig2', '-s', '-p', '-v', '-S']
@ -840,21 +845,28 @@ def jbig2_10to1(
proc.check_returncode()
log.debug(proc.stderr)
jbig2_globals_xref = doc._getNewXref()
log.info(jbig2_globals_xref)
doc._updateStream(xref, (root / 'output.sym').read_bytes())
pike = pikepdf.Pdf.open(output_file + '_tmp.pdf')
jbig2_globals_data = (root / 'output.sym').read_bytes()
jbig2_globals = pikepdf.Stream(pike, jbig2_globals_data)
jbig2_globals_indirect = pike.make_indirect(jbig2_globals)
for n, xref in enumerate(changed_xrefs):
jbig2_im_file = root / 'output.{:04d}'.format(n)
obj_str = doc._getObjectString(xref)
jbig2_im_data = jbig2_im_file.read_bytes()
im_obj = pike._get_object_id(xref, 0)
log.info(xref)
log.info(obj_str)
obj_str = obj_str.replace('/Filter/FlateDecode', '/Filter/JBIG2Decode')
obj_str = obj_str.replace(
'>>', '/DecodeParms << /JBIG2Globals {} 0 R >> >>'.format(jbig2_globals_xref))
doc._updateObject(xref, obj_str)
doc._updateStream(xref, jbig2_im_file.read_bytes())
doc.save(output_file, garbage=0, deflate=0, clean=0, expand=0)
log.info(repr(im_obj))
im_obj.write(
jbig2_im_data, pikepdf.Name('/JBIG2Decode'),
pikepdf.Dictionary({
'/JBIG2Globals': pike.make_indirect(jbig2_globals_indirect)
})
)
log.info(repr(im_obj))
pike.save(output_file, preserve_pdfa=True)
def ocr_tesseract_and_render_pdf(
@ -1341,7 +1353,7 @@ def build_pipeline(options, work_folder, log, context):
output=os.path.join(work_folder, r'\1x.opt.pdf'),
extras=[log, context])
task_jbig2_10to1.graphviz(fillcolor='"#00cc66"')
task_jbig2_10to1.active_if(fitz and (options.pdf_renderer == 'hocr' or
task_jbig2_10to1.active_if((options.pdf_renderer == 'hocr' or
options.pdf_renderer == 'sandwich'))
# Tesseract OCR+PDF