BUG: Consider BlackIs1 parameter for CCITTFaxDecode filter (#3196)

Closes #3193.

Author: stefan6419846

docs/user/cropping-and-transforming.md

@@ -179,7 +179,7 @@ writer.write("out-pg-transform.pdf")
 
 ### Scaling the page only
 
-To scale the page by `sx` in the X direction and `sy` in the Y direction: 
+To scale the page by `sx` in the X direction and `sy` in the Y direction:
 
 ```python
 from pypdf.generic import RectangleObject

pypdf/filters.py

@@ -59,6 +59,7 @@
 from .errors import DeprecationError, PdfReadError, PdfStreamError
 from .generic import (
     ArrayObject,
+    BooleanObject,
     DictionaryObject,
     IndirectObject,
     NullObject,
@@ -755,6 +756,11 @@ def _apply_alpha(
     # Get filters
     filters = x_object_obj.get(SA.FILTER, NullObject()).get_object()
     lfilters = filters[-1] if isinstance(filters, list) else filters
+    decode_parms = x_object_obj.get(SA.DECODE_PARMS, None)
+    if isinstance(decode_parms, (tuple, list)):
+        decode_parms = decode_parms[0]
+    else:
+        decode_parms = {}
 
     extension = None
     if lfilters in (FT.FLATE_DECODE, FT.RUN_LENGTH_DECODE):
@@ -816,6 +822,10 @@ def _apply_alpha(
         img, x_object_obj, obj_as_text, image_format, extension
     )
 
+    if lfilters == FT.CCITT_FAX_DECODE and decode_parms.get("/BlackIs1", BooleanObject(False)).value is True:
+        from PIL import ImageOps
+        img = ImageOps.invert(img)
+
     # Save image to bytes
     img_byte_arr = BytesIO()
     try:

tests/test_filters.py

@@ -8,7 +8,7 @@
 from pathlib import Path
 
 import pytest
-from PIL import Image
+from PIL import Image, ImageOps
 
 from pypdf import PdfReader
 from pypdf.errors import DeprecationError, PdfReadError
@@ -642,3 +642,17 @@ def test_ascii85decode__non_recoverable(caplog):
     with pytest.raises(ValueError, match="Non-Ascii85 digit found: Ã"):
         ASCII85Decode.decode(data)
     assert caplog.text == ""
+
+
+@pytest.mark.enable_socket
+def test_ccitt_fax_decode__black_is_1():
+    url = "https://github.com/user-attachments/files/19288881/imagemagick-CCITTFaxDecode_BlackIs1-true.pdf"
+    name = "issue3193.pdf"
+    reader = PdfReader(BytesIO(get_data_from_url(url, name=name)))
+    other_reader = PdfReader(RESOURCE_ROOT / "imagemagick-CCITTFaxDecode.pdf")
+
+    actual_image = reader.pages[0].images[0].image
+    expected_image_inverted = other_reader.pages[0].images[0].image
+    expected_pixels = list(ImageOps.invert(expected_image_inverted).getdata())
+    actual_pixels = list(actual_image.getdata())
+    assert expected_pixels == actual_pixels