UnisMindMap/mineru/utils/pdf_reader.py

113 lines
3.2 KiB
Python

# Copyright (c) Opendatalab. All rights reserved.
import base64
from io import BytesIO
from loguru import logger
from PIL import Image
from pypdfium2 import PdfBitmap, PdfDocument, PdfPage
def page_to_image(
page: PdfPage,
dpi: int = 200,
max_width_or_height: int = 3500, # changed from 4500 to 3500
) -> (Image.Image, float):
scale = dpi / 72
long_side_length = max(*page.get_size())
if (long_side_length*scale) > max_width_or_height:
scale = max_width_or_height / long_side_length
bitmap: PdfBitmap = page.render(scale=scale) # type: ignore
image = bitmap.to_pil()
try:
bitmap.close()
except Exception as e:
logger.error(f"Failed to close bitmap: {e}")
return image, scale
def image_to_bytes(
image: Image.Image,
# image_format: str = "PNG", # 也可以用 "JPEG"
image_format: str = "JPEG",
) -> bytes:
with BytesIO() as image_buffer:
image.save(image_buffer, format=image_format)
return image_buffer.getvalue()
def image_to_b64str(
image: Image.Image,
# image_format: str = "PNG", # 也可以用 "JPEG"
image_format: str = "JPEG",
) -> str:
image_bytes = image_to_bytes(image, image_format)
return base64.b64encode(image_bytes).decode("utf-8")
def base64_to_pil_image(
base64_str: str,
) -> Image.Image:
"""Convert base64 string to PIL Image."""
image_bytes = base64.b64decode(base64_str)
with BytesIO(image_bytes) as image_buffer:
return Image.open(image_buffer).convert("RGB")
def pdf_to_images(
pdf: str | bytes | PdfDocument,
dpi: int = 200,
max_width_or_height: int = 3500,
start_page_id: int = 0,
end_page_id: int | None = None,
) -> list[Image.Image]:
doc = pdf if isinstance(pdf, PdfDocument) else PdfDocument(pdf)
page_num = len(doc)
end_page_id = end_page_id if end_page_id is not None and end_page_id >= 0 else page_num - 1
if end_page_id > page_num - 1:
logger.warning("end_page_id is out of range, use images length")
end_page_id = page_num - 1
images = []
try:
for i in range(start_page_id, end_page_id + 1):
image, _ = page_to_image(doc[i], dpi, max_width_or_height)
images.append(image)
finally:
try:
doc.close()
except Exception:
pass
return images
def pdf_to_images_bytes(
pdf: str | bytes | PdfDocument,
dpi: int = 200,
max_width_or_height: int = 3500,
start_page_id: int = 0,
end_page_id: int | None = None,
# image_format: str = "PNG", # 也可以用 "JPEG"
image_format: str = "JPEG",
) -> list[bytes]:
images = pdf_to_images(pdf, dpi, max_width_or_height, start_page_id, end_page_id)
return [image_to_bytes(image, image_format) for image in images]
def pdf_to_images_b64strs(
pdf: str | bytes | PdfDocument,
dpi: int = 200,
max_width_or_height: int = 3500,
start_page_id: int = 0,
end_page_id: int | None = None,
# image_format: str = "PNG", # 也可以用 "JPEG"
image_format: str = "JPEG",
) -> list[str]:
images = pdf_to_images(pdf, dpi, max_width_or_height, start_page_id, end_page_id)
return [image_to_b64str(image, image_format) for image in images]