PDF rendering with poppler-qt5

poppler_qt5.py

# SPDX-FileCopyrightText: 2024 geisserml <[email protected]>
# SPDX-License-Identifier: MPL-2.0
# Note that Poppler is GPL-licensed, so this code is altogether affected by copyleft

import io
import PIL.Image
from popplerqt5 import Poppler
from PyQt5.QtCore import QByteArray, QBuffer


def _translate_rotation(rotation):
    r_enum = Poppler.Page.Rotation
    return {
        0: r_enum.Rotate0,
        90: r_enum.Rotate90,
        180: r_enum.Rotate180,
        270: r_enum.Rotate270,
    }[rotation]


def invoke_poppler_qt5(filepath, index, scale=4, rotation=0, password=None):
    
    # Note, as of this writing, poppler does not take /UserUnit into account.
    
    if password is None:
        pdf = Poppler.Document.load(filepath)
    else:
        qb_password = QByteArray(password.encode('ascii'))
        pdf = Poppler.Document.load(filepath, qb_password, qb_password)
    
    pdf.setRenderHint(Poppler.Document.Antialiasing)
    pdf.setRenderHint(Poppler.Document.TextAntialiasing)
    
    page = pdf.page(index)
    dpi = scale * 72
    
    qimage = page.renderToImage(  # TODO use kwargs?
        dpi, dpi,
        -1, -1, -1, -1,
        _translate_rotation(rotation),
    )
    
    qbuffer = QBuffer()
    qbuffer.open(QBuffer.ReadWrite)
    qimage.save(qbuffer, "PPM")
    qbuffer.close()
    
    return PIL.Image.open( io.BytesIO(qbuffer.data()) )