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info.py: linearize O(n^2) search for use images on a page

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James R. Barlow 2020-03-18 22:59:18 -07:00
parent 82142fe5ef
commit f35a2303bb
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GPG Key ID: 4434EB74C4A35F7F
1 changed files with 8 additions and 9 deletions
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17
src/ocrmypdf/pdfinfo/info.py
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@ -18,7 +18,7 @@
import logging import logging
import re import re
from collections import namedtuple from collections import defaultdict, namedtuple
from decimal import Decimal from decimal import Decimal
from enum import Enum from enum import Enum
from math import hypot, isclose from math import hypot, isclose
@ -98,7 +98,7 @@ XobjectSettings = namedtuple('XobjectSettings', ['name', 'shorthand', 'stack_dep
InlineSettings = namedtuple('InlineSettings', ['iimage', 'shorthand', 'stack_depth']) InlineSettings = namedtuple('InlineSettings', ['iimage', 'shorthand', 'stack_depth'])
ContentsInfo = namedtuple( ContentsInfo = namedtuple(
'ContentsInfo', ['xobject_settings', 'inline_images', 'found_vector'] 'ContentsInfo', ['xobject_settings', 'inline_images', 'found_vector', 'name_index']
) )
TextboxInfo = namedtuple('TextboxInfo', ['bbox', 'is_visible', 'is_corrupt']) TextboxInfo = namedtuple('TextboxInfo', ['bbox', 'is_visible', 'is_corrupt'])
@ -151,6 +151,7 @@ def _interpret_contents(contentstream, initial_shorthand=UNIT_SQUARE):
ctm = PdfMatrix(initial_shorthand) ctm = PdfMatrix(initial_shorthand)
xobject_settings = [] xobject_settings = []
inline_images = [] inline_images = []
name_index = defaultdict(lambda: [])
found_vector = False found_vector = False
vector_ops = set('S s f F f* B B* b b*'.split()) vector_ops = set('S s f F f* B B* b b*'.split())
image_ops = set('BI ID EI q Q Do cm'.split()) image_ops = set('BI ID EI q Q Do cm'.split())
@ -185,6 +186,7 @@ def _interpret_contents(contentstream, initial_shorthand=UNIT_SQUARE):
name=image_name, shorthand=ctm.shorthand, stack_depth=len(stack) name=image_name, shorthand=ctm.shorthand, stack_depth=len(stack)
) )
xobject_settings.append(settings) xobject_settings.append(settings)
name_index[image_name].append(settings)
elif operator == 'INLINE IMAGE': # BI/ID/EI are grouped into this elif operator == 'INLINE IMAGE': # BI/ID/EI are grouped into this
iimage = operands[0] iimage = operands[0]
inline = InlineSettings( inline = InlineSettings(
@ -198,6 +200,7 @@ def _interpret_contents(contentstream, initial_shorthand=UNIT_SQUARE):
xobject_settings=xobject_settings, xobject_settings=xobject_settings,
inline_images=inline_images, inline_images=inline_images,
found_vector=found_vector, found_vector=found_vector,
name_index=name_index,
) )
@ -419,13 +422,9 @@ def _find_regular_images(container, contentsinfo):
""" """
for pdfimage, xobj in _image_xobjects(container): for pdfimage, xobj in _image_xobjects(container):
if xobj not in contentsinfo.name_index:
# For each image that is drawn on this, check if we drawing the continue
# current image - yes this is O(n^2), but n == 1 almost always for draw in contentsinfo.name_index[xobj]:
for draw in contentsinfo.xobject_settings:
if draw.name != xobj:
continue
if draw.stack_depth == 0 and _is_unit_square(draw.shorthand): if draw.stack_depth == 0 and _is_unit_square(draw.shorthand):
# At least one PDF in the wild (and test suite) draws an image # At least one PDF in the wild (and test suite) draws an image
# when the graphics stack depth is 0, meaning that the image # when the graphics stack depth is 0, meaning that the image