From 2fefed89d96d8367d33b926f9b1f4f167c79f7e1 Mon Sep 17 00:00:00 2001
From: j-t-1 <120829237+j-t-1@users.noreply.github.com>
Date: Wed, 24 Jul 2024 10:26:54 +0100
Subject: [PATCH 1/2] STY: Simplify paeth_predictor

---
 pypdf/_utils.py | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/pypdf/_utils.py b/pypdf/_utils.py
index 38c0d67d7..9587a0728 100644
--- a/pypdf/_utils.py
+++ b/pypdf/_utils.py
@@ -396,12 +396,7 @@ def paeth_predictor(left: int, up: int, up_left: int) -> int:
     dist_up = abs(p - up)
     dist_up_left = abs(p - up_left)
 
-    if dist_left <= dist_up and dist_left <= dist_up_left:
-        return left
-    elif dist_up <= dist_up_left:
-        return up
-    else:
-        return up_left
+    return min((left, dist_left), (up, dist_up), (up_left, dist_up_left), key=lambda x: x[1])[0]
 
 
 def deprecate(msg: str, stacklevel: int = 3) -> None:

From 413f3d00fdc860a4e69df593fd52778b5ecaa00e Mon Sep 17 00:00:00 2001
From: j-t-1 <120829237+j-t-1@users.noreply.github.com>
Date: Thu, 25 Jul 2024 14:41:34 +0100
Subject: [PATCH 2/2] DEP: Remove paeth_predictor

This function is unused.
---
 pypdf/_utils.py     |  9 ---------
 tests/test_utils.py | 18 ------------------
 2 files changed, 27 deletions(-)

diff --git a/pypdf/_utils.py b/pypdf/_utils.py
index 9587a0728..6569707b6 100644
--- a/pypdf/_utils.py
+++ b/pypdf/_utils.py
@@ -390,15 +390,6 @@ def ord_(b: Union[int, str, bytes]) -> Union[int, bytes]:
 WHITESPACES_AS_REGEXP = b"[" + WHITESPACES_AS_BYTES + b"]"
 
 
-def paeth_predictor(left: int, up: int, up_left: int) -> int:
-    p = left + up - up_left
-    dist_left = abs(p - left)
-    dist_up = abs(p - up)
-    dist_up_left = abs(p - up_left)
-
-    return min((left, dist_left), (up, dist_up), (up_left, dist_up_left), key=lambda x: x[1])[0]
-
-
 def deprecate(msg: str, stacklevel: int = 3) -> None:
     warnings.warn(msg, DeprecationWarning, stacklevel=stacklevel)
 
diff --git a/tests/test_utils.py b/tests/test_utils.py
index 81fcf9fb4..856bedd86 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -132,24 +132,6 @@ def test_deprecate_no_replacement():
     assert warn[0].message.args[0] == error_msg
 
 
-@pytest.mark.parametrize(
-    ("left", "up", "upleft", "expected"),
-    [
-        (0, 0, 0, 0),
-        (1, 0, 0, 1),
-        (0, 1, 0, 1),
-        (0, 0, 1, 0),
-        (1, 2, 3, 1),
-        (2, 1, 3, 1),
-        (1, 3, 2, 2),
-        (3, 1, 2, 2),
-        (3, 2, 1, 3),
-    ],
-)
-def test_paeth_predictor(left, up, upleft, expected):
-    assert pypdf._utils.paeth_predictor(left, up, upleft) == expected
-
-
 @pytest.mark.parametrize(
     ("dat", "pos", "to_read", "expected", "expected_pos"),
     [