Refactor dictionary based image info to ImageInfo
This commit is contained in:
James R. Barlow
+146
-91
@@ -8,7 +8,7 @@ import re
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import sys
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import PyPDF2 as pypdf
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from collections import namedtuple
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from collections.abc import MutableMapping
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from collections.abc import MutableMapping, Mapping
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import warnings
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from pathlib import Path
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@@ -234,38 +234,137 @@ def _get_dpi(ctm_shorthand, image_size):
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dpi_w = scale_w * 72.0
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dpi_h = scale_h * 72.0
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return (dpi_w, dpi_h)
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return dpi_w, dpi_h
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class ImageInfo:
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DPI_PREC = Decimal('1.000')
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def __init__(self, *, name='', pdfimage=None, inline=None,
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shorthand=None):
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self._name = name
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self._shorthand = shorthand
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if inline:
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# Fixme does not work for inline images with non abbreviated
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# fields
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self._origin = 'inline'
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self._width = inline.settings['/W']
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self._height = inline.settings['/H']
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self._bpc = inline.settings.get('/BPC', 8)
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try:
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self._color = FRIENDLY_COLORSPACE[inline.settings['/CS']]
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except Exception:
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self._color = '-'
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self._comp = FRIENDLY_COMP.get(self._color, '?')
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if '/F' in inline.settings:
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filter_ = inline.settings['/F']
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if isinstance(filter_, pypdf.generic.ArrayObject):
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filter_ = filter_[0]
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self._enc = FRIENDLY_ENCODING.get(filter_, 'image')
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else:
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self._enc = 'image'
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elif pdfimage:
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self._origin = 'xobject'
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self._width = pdfimage['/Width']
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self._height = pdfimage['/Height']
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if '/BitsPerComponent' in pdfimage:
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self._bpc = pdfimage['/BitsPerComponent']
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else:
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self._bpc = 8
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# Fixme: this is incorrectly treats explicit masks as stencil masks,
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# but good enough for now. Explicit masks have /ImageMask true but are
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# never called for in content stream, instead are drawn as a /Mask on
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# other images. For our purposes finding out the details of /Mask
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# will seldom matter.
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if '/ImageMask' in pdfimage:
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self._type = 'stencil' if pdfimage['/ImageMask'].value \
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else 'image'
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else:
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self._type = 'image'
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if '/Filter' in pdfimage:
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filter_ = pdfimage['/Filter']
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if isinstance(filter_, pypdf.generic.ArrayObject):
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filter_ = filter_[0]
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self._enc = FRIENDLY_ENCODING.get(filter_, 'image')
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else:
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self._enc = 'image'
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if '/ColorSpace' in pdfimage:
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cs = pdfimage['/ColorSpace']
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if isinstance(cs, pypdf.generic.ArrayObject):
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cs = cs[0]
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self._color = FRIENDLY_COLORSPACE.get(cs, '-')
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else:
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self._color = 'jpx' if self._enc == 'jpx' else '?'
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self._comp = FRIENDLY_COMP.get(self._color, '?')
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# Bit of a hack... infer grayscale if component count is uncertain
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# but encoding must be monochrome. This happens if a monochrome image
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# has an ICC profile attached. Better solution would be to examine
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# the ICC profile.
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if self._comp == '?' and self._enc in ('ccitt', 'jbig2'):
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self._comp = FRIENDLY_COMP['gray']
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@property
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def name(self):
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return self._name
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@property
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def width(self):
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return self._width
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@property
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def height(self):
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return self._height
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@property
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def bpc(self):
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return self._bpc
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@property
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def color(self):
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return self._color
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@property
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def comp(self):
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return self._comp
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@property
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def enc(self):
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return self._enc
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@property
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def xres(self):
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return _get_dpi(self._shorthand, (self._width, self._height))[0]
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@property
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def yres(self):
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return _get_dpi(self._shorthand, (self._width, self._height))[1]
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def __getitem__(self, item):
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warnings.warn("ImageInfo.__getitem__", DeprecationWarning)
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if item in ('name', 'width', 'height', 'bpc', 'color', 'comp', 'enc'):
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return getattr(self, item)
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elif item == 'dpi_w':
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return Decimal(self.xres).quantize(self.DPI_PREC)
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elif item == 'dpi_h':
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return Decimal(self.yres).quantize(self.DPI_PREC)
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elif item == 'dpi':
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return Decimal(self.xres * self.yres).sqrt().quantize(
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self.DPI_PREC)
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else:
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raise KeyError(item)
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def _find_inline_images(contentsinfo):
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"Find inline images in the contentstream"
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for n, inline in enumerate(contentsinfo.inline_images):
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image = {}
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image['name'] = str('inline-%02d' % n)
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image['width'] = inline.settings['/W']
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image['height'] = inline.settings['/H']
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if '/BPC' in inline.settings:
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image['bpc'] = inline.settings['/BPC']
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else:
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image['bpc'] = 8
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if '/CS' in inline.settings:
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image['color'] = FRIENDLY_COLORSPACE.get(inline.settings['/CS'], '-')
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else:
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image['color'] = '-'
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image['comp'] = FRIENDLY_COMP.get(image['color'], '?')
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if '/F' in inline.settings:
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filter_ = inline.settings['/F']
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if isinstance(filter_, pypdf.generic.ArrayObject):
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filter_ = filter_[0]
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image['enc'] = FRIENDLY_ENCODING.get(filter_, 'image')
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else:
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image['enc'] = 'image'
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dpi_w, dpi_h = _get_dpi(
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inline.shorthand, (image['width'], image['height']))
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image['dpi_w'], image['dpi_h'] = Decimal(dpi_w), Decimal(dpi_h)
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yield image
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yield ImageInfo(name='inline-%02d' % n, shorthand=inline.shorthand,
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inline=inline)
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def _image_xobjects(container):
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@@ -289,8 +388,8 @@ def _image_xobjects(container):
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for xobj in resources['/XObject']:
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candidate = resources['/XObject'][xobj]
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if candidate['/Subtype'] == '/Image':
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image = candidate
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yield (image, xobj)
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pdfimage = candidate
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yield (pdfimage, xobj)
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def _find_regular_images(container, contentsinfo):
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@@ -304,57 +403,14 @@ def _find_regular_images(container, contentsinfo):
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"""
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for pdfimage, xobj in _image_xobjects(container):
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image = {}
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image['name'] = xobj
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image['width'] = pdfimage['/Width']
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image['height'] = pdfimage['/Height']
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if '/BitsPerComponent' in pdfimage:
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image['bpc'] = pdfimage['/BitsPerComponent']
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else:
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image['bpc'] = 8
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# Fixme: this is incorrectly treats explicit masks as stencil masks,
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# but good enough for now. Explicit masks have /ImageMask true but are
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# never called for in content stream, instead are drawn as a /Mask on
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# other images. For our purposes finding out the details of /Mask
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# will seldom matter.
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if '/ImageMask' in pdfimage:
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image['type'] = 'stencil' if pdfimage['/ImageMask'].value \
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else 'image'
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else:
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image['type'] = 'image'
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if '/Filter' in pdfimage:
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filter_ = pdfimage['/Filter']
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if isinstance(filter_, pypdf.generic.ArrayObject):
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filter_ = filter_[0]
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image['enc'] = FRIENDLY_ENCODING.get(filter_, 'image')
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else:
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image['enc'] = 'image'
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if '/ColorSpace' in pdfimage:
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cs = pdfimage['/ColorSpace']
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if isinstance(cs, pypdf.generic.ArrayObject):
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cs = cs[0]
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image['color'] = FRIENDLY_COLORSPACE.get(cs, '-')
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else:
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image['color'] = 'jpx' if image['enc'] == 'jpx' else '?'
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image['comp'] = FRIENDLY_COMP.get(image['color'], '?')
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# Bit of a hack... infer grayscale if component count is uncertain
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# but encoding must be monochrome. This happens if a monochrome image
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# has an ICC profile attached. Better solution would be to examine
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# the ICC profile.
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if image['comp'] == '?' and image['enc'] in ('ccitt', 'jbig2'):
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image['comp'] = FRIENDLY_COMP['gray']
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image['dpi_w'] = image['dpi_h'] = 0
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for xobj in contentsinfo.xobject_settings:
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# Loop in case the same image is display multiple times on a page
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if xobj.name != image['name']:
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# For each image that is drawn on this, check if we drawing the
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# current image - yes this is O(n^2), but n == 1 almost always
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for draw in contentsinfo.xobject_settings:
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if draw.name != xobj:
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continue
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if xobj.stack_depth == 0 and _is_unit_square(xobj.shorthand):
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if draw.stack_depth == 0 and _is_unit_square(draw.shorthand):
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# At least one PDF in the wild (and test suite) draws an image
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# when the graphics stack depth is 0, meaning that the image
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# gets drawn into a square of 1x1 PDF units (or 1/72",
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@@ -362,20 +418,8 @@ def _find_regular_images(container, contentsinfo):
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# these from our DPI calculation for the page.
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continue
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dpi_w, dpi_h = _get_dpi(
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xobj.shorthand, (image['width'], image['height']))
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# When image is used multiple times take the highest DPI it is
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# rendered at
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image['dpi_w'] = max(dpi_w, image.get('dpi_w', 0))
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image['dpi_h'] = max(dpi_h, image.get('dpi_h', 0))
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DPI_PREC = Decimal('1.000')
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dpi = Decimal(image['dpi_w'] * image['dpi_h']).sqrt()
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image['dpi_w'] = Decimal(image['dpi_w']).quantize(DPI_PREC)
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image['dpi_h'] = Decimal(image['dpi_h']).quantize(DPI_PREC)
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image['dpi'] = dpi.quantize(DPI_PREC)
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yield image
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yield ImageInfo(name=draw.name, pdfimage=pdfimage, shorthand=
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draw.shorthand)
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def _find_form_xobject_images(pdf, container, contentsinfo):
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@@ -592,6 +636,14 @@ class PageInfo(MutableMapping):
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def __delitem__(self, key):
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del self._pageinfo[key]
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def __repr__(self):
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return (
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'<PageInfo '
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'pageno={} {}"x{}" rotation={} res={}x{} has_text={}>').format(
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self.pageno, self.width_inches, self.height_inches,
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self.xres, self.yres, self.has_text
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)
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class PdfInfo:
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def __init__(self, infile):
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@@ -607,6 +659,9 @@ class PdfInfo:
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def __len__(self):
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return len(self._pages)
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def __repr__(self):
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return "<PdfInfo('...'), page count={}>".format(len(self))
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def main():
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import argparse
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