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JBIG2: refactor, don't recompress existing JBIG2

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This commit is contained in:
James R. Barlow
2018-04-09 13:04:10 -07:00
parent e40228102c
commit c9dd330766
1 changed files with 21 additions and 24 deletions
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45
src/ocrmypdf/pipeline.py
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@@ -1054,6 +1054,7 @@ def optimize_pdf(
output_file,
log,
context):
import fitz
import pikepdf
@@ -1066,24 +1067,30 @@ def optimize_pdf(
def make_img_name(xref):
return str(root / '{:08d}.png'.format(xref))
# Write all images out
PAGE_GROUP_SIZE = 20
# Extract images we can improve
PAGE_GROUP_SIZE = 10
changed_xrefs = set()
from collections import defaultdict
image_groups = defaultdict(lambda: [])
jbig2_groups = defaultdict(lambda: [])
for pageno in range(doc.pageCount):
group, index = divmod(pageno, PAGE_GROUP_SIZE)
page_images = doc.getPageImageList(pageno)
for image in page_images:
xref, smask, w, h, bpc, cs, alt_cs, name, filt = image
if xref in changed_xrefs:
continue
if bpc != 1:
continue
pix = fitz.Pixmap(doc, xref)
pix.writePNG(make_img_name(xref), savealpha=False)
changed_xrefs.add(xref)
image_groups[group].append(xref)
continue # Don't improve same image twice
if bpc == 1 and filt != 'JBIG2Decode':
# Monochrome: convert to JBIG2 if not already
pix = fitz.Pixmap(doc, xref)
pix.writePNG(make_img_name(xref), savealpha=False)
changed_xrefs.add(xref)
jbig2_groups[group].append(xref)
elif filt == 'DCTDecode':
# JPEG: apply quality setting
# would have to use pike to get the raw DCT because fitz
# has no API for it...
# or leptonica convertToPdfData
pass
from subprocess import run, PIPE
import concurrent.futures
@@ -1091,8 +1098,8 @@ def optimize_pdf(
with concurrent.futures.ThreadPoolExecutor(
max_workers=options.jobs) as executor:
futures = []
for imgrp, xrefs in image_groups.items():
prefix = 'group{:08d}'.format(imgrp)
for group, xrefs in jbig2_groups.items():
prefix = 'group{:08d}'.format(group)
cmd = ['jbig2', '-b', prefix, '-s', '-p', '-S']
cmd.extend(make_img_name(xref) for xref in xrefs)
future = executor.submit(
@@ -1105,8 +1112,8 @@ def optimize_pdf(
pike = pikepdf.Pdf.open(input_file)
for imgrp, xrefs in image_groups.items():
prefix = 'group{:08d}'.format(imgrp)
for group, xrefs in jbig2_groups.items():
prefix = 'group{:08d}'.format(group)
jbig2_globals_data = (root / (prefix + '.sym')).read_bytes()
jbig2_globals = pikepdf.Stream(pike, jbig2_globals_data)
@@ -1361,16 +1368,6 @@ def build_pipeline(options, work_folder, log, context):
task_combine_layers.active_if(options.pdf_renderer == 'hocr' or
options.pdf_renderer == 'sandwich')
# task_jbig2_10to1 = main_pipeline.collate(
# task_func=jbig2_10to1,
# input=[combine_layers],
# filter=regex(r".*/(\d{5})(\d)(?:\.rendered\.pdf)"),
# output=os.path.join(work_folder, r'\1x.opt.pdf'),
# extras=[log, context])
# task_jbig2_10to1.graphviz(fillcolor='"#00cc66"')
# task_jbig2_10to1.active_if((options.pdf_renderer == 'hocr' or
# options.pdf_renderer == 'sandwich'))
# Tesseract OCR+PDF
task_ocr_tesseract_and_render_pdf = main_pipeline.collate(
task_func=ocr_tesseract_and_render_pdf,