PDF rendering with poppler-gtk

poppler_gtk.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 math
from pathlib import Path
import PIL.Image

import cairo
import gi
gi.require_version('Poppler', '0.18')
from gi.repository import Poppler


def invoke_poppler_gtk(filepath, index, scale=4, rotation=0, password=None):
    
    # Note, as of this writing, poppler does not take /UserUnit into account.
    
    pdf = Poppler.Document.new_from_file(pathlib.Path(filepath).as_uri(), password)
    page = pdf.get_page(index)
    
    width, height = page.get_size()
    width, height = math.ceil(width), math.ceil(height)
    sc_width, sc_height = math.ceil(width*scale), math.ceil(height*scale)
    
    if rotation in (90, 270):
        width, height = height, width
        sc_width, sc_height = sc_height, sc_width
    
    cr_surface = cairo.ImageSurface(cairo.Format.ARGB32, sc_width, sc_height)
    cr_context = cairo.Context(cr_surface)
    
    cr_context.scale(scale, scale)
    cr_context.set_source_rgba(255, 255, 255, 255)
    cr_context.rectangle(0, 0, width, height)
    cr_context.fill()
    
    cr_context.rotate((rotation/180) * math.pi)  # TODO math.radians(rotation)
    if rotation == 90:
        cr_context.translate(0, -width)
    elif rotation == 180:
        cr_context.translate(-width, -height)
    elif rotation == 270:
        cr_context.translate(-height, 0)
    
    page.render(cr_context)
    pil_image = PIL.Image.frombytes(
        "RGBA",
        (sc_width, sc_height),
        bytes(cr_surface.get_data()),
        "raw",
        "BGRa",
        0, 1,
    )
    
    return pil_image