182 lines
5.0 KiB
Python
182 lines
5.0 KiB
Python
import atexit
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import io
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from functools import partial, lru_cache
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from itertools import chain, starmap, filterfalse, repeat
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from operator import itemgetter
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from typing import List
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import fitz
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from PIL import Image
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from funcy import rcompose, merge, zipdict
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from tqdm import tqdm
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from image_prediction.image_extractor.extractor import ImageExtractor, ImageMetadataPair
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from image_prediction.info import Info
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from image_prediction.stitching.stitching import stitch_pairs
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from image_prediction.stitching.utils import validate_box_coords, validate_box_size
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class ParsablePDFImageExtractor(ImageExtractor):
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def __init__(self, verbose=False, tolerance=0):
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"""
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Args:
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verbose: Whether to show progressbar
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tolerance: The tolerance in pixels for the distance images beyond which they will not be stitched together
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"""
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self.doc: fitz.fitz.Document = None
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self.verbose = verbose
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self.tolerance = tolerance
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def extract(self, pdf: bytes, page_range: range = None):
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self.doc = fitz.Document(stream=pdf)
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pages = extract_pages(self.doc, page_range) if page_range else self.doc
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image_metadata_pairs = chain.from_iterable(
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map(
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self.__process_images_on_page,
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tqdm(pages, desc="Extracting", disable=not self.verbose, total=len(page_range) if page_range else None),
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)
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)
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yield from image_metadata_pairs
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def __process_images_on_page(self, page: fitz.fitz.Page):
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images = get_images_on_page(self.doc, page)
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metadata = get_metadata_for_images_on_page(self.doc, page)
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clear_caches()
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image_metadata_pairs = starmap(ImageMetadataPair, filter(all, zip(images, metadata)))
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image_metadata_pairs = stitch_pairs(list(image_metadata_pairs), tolerance=self.tolerance)
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yield from image_metadata_pairs
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def extract_pages(doc, page_range):
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page_range = range(page_range.start + 1, page_range.stop + 1)
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pages = map(doc.load_page, page_range)
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return pages
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@lru_cache(maxsize=None)
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def get_images_on_page(doc, page: fitz.Page):
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image_infos = get_image_infos(page)
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xrefs = map(itemgetter("xref"), image_infos)
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images = map(partial(xref_to_image, doc), xrefs)
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return images
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def get_metadata_for_images_on_page(doc, page: fitz.Page):
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metadata = map(get_image_metadata, get_image_infos(page))
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metadata = validate_coords_and_passthrough(metadata)
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metadata = filter_out_tiny_images(metadata)
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metadata = validate_size_and_passthrough(metadata)
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metadata = add_page_metadata(page, metadata)
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metadata = add_alpha_channel_info(doc, page, metadata)
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yield from metadata
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@lru_cache(maxsize=None)
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def get_image_infos(page: fitz.Page) -> List[dict]:
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return page.get_image_info(xrefs=True)
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@lru_cache(maxsize=None)
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def xref_to_image(doc, xref) -> Image:
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maybe_image = load_image_handle_from_xref(doc, xref)
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return Image.open(io.BytesIO(maybe_image["image"])) if maybe_image else None
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def get_image_metadata(image_info):
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x1, y1, x2, y2 = map(rounder, image_info["bbox"])
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width = abs(x2 - x1)
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height = abs(y2 - y1)
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return {
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Info.WIDTH: width,
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Info.HEIGHT: height,
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Info.X1: x1,
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Info.X2: x2,
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Info.Y1: y1,
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Info.Y2: y2,
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}
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def validate_coords_and_passthrough(metadata):
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yield from map(validate_box_coords, metadata)
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def filter_out_tiny_images(metadata):
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return filterfalse(tiny, metadata)
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def validate_size_and_passthrough(metadata):
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yield from map(validate_box_size, metadata)
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def add_page_metadata(page, metadata):
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return map(partial(merge, get_page_metadata(page)), metadata)
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def add_alpha_channel_info(doc, page, metadata):
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xrefs = map(itemgetter("xref"), get_image_infos(page))
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alpha = map(partial(has_alpha_channel, doc), xrefs)
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alpha = ({Info.ALPHA: a} for a in alpha)
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# alpha = map(dict, zip(repeat(Info.ALPHA), alpha))
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metadata = starmap(merge, zip(alpha, metadata))
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return metadata
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@lru_cache(maxsize=None)
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def load_image_handle_from_xref(doc, xref):
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return doc.extract_image(xref)
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rounder = rcompose(round, int)
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def get_page_metadata(page):
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page_width, page_height = map(rounder, page.mediabox_size)
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return {
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Info.PAGE_WIDTH: page_width,
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Info.PAGE_HEIGHT: page_height,
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Info.PAGE_IDX: page.number,
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}
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def has_alpha_channel(doc, xref):
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maybe_image = load_image_handle_from_xref(doc, xref)
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maybe_smask = maybe_image["smask"] if maybe_image else None
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if maybe_smask:
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return any([doc.extract_image(maybe_smask) is not None, bool(fitz.Pixmap(doc, maybe_smask).alpha)])
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else:
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return bool(fitz.Pixmap(doc, xref).alpha)
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def tiny(metadata):
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return metadata[Info.WIDTH] * metadata[Info.HEIGHT] <= 4
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def clear_caches():
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get_image_infos.cache_clear()
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load_image_handle_from_xref.cache_clear()
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get_images_on_page.cache_clear()
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xref_to_image.cache_clear()
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atexit.register(clear_caches)
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