Bug in mediabox expansion when applying non-right angle rotation

pypdf/_page.py

@@ -1655,11 +1655,6 @@ def add_transformation(
 
             lowerleft = (min(new_x), min(new_y))
             upperright = (max(new_x), max(new_y))
-            lowerleft = (min(corners[0], lowerleft[0]), min(corners[1], lowerleft[1]))
-            upperright = (
-                max(corners[2], upperright[0]),
-                max(corners[3], upperright[1]),
-            )
 
             self.mediabox.lower_left = lowerleft
             self.mediabox.upper_right = upperright

tests/test_page.py

@@ -1,5 +1,6 @@
 """Test the pypdf._page module."""
 import json
+import math
 from copy import deepcopy
 from io import BytesIO
 from pathlib import Path
@@ -122,6 +123,34 @@ def test_page_operations(pdf_path, password):
     page.extract_text()
 
 
+@pytest.mark.parametrize(
+    ("angle", "expected_width", "expected_height"),
+    [
+        (175, 680, 844),
+        (45, 994, 994),
+        (-80, 888, 742),
+    ]
+)
+def test_mediabox_expansion_after_rotation(angle: float, expected_width: int, expected_height: int):
+    """
+    Mediabox dimensions after rotation at a non-right angle with expension are correct.
+
+    The test was validated against pillow (see PR #2282)
+    """
+    pdf_path = RESOURCE_ROOT / "crazyones.pdf"
+    reader = PdfReader(pdf_path)
+
+    transformation = Transformation().rotate(angle)
+    for page_box in reader.pages:
+        page_box.add_transformation(transformation, expand=True)
+
+    mediabox = reader.pages[0].mediabox
+
+    # Deviation of upto 2 pixels is acceptable
+    assert math.isclose(mediabox.width, expected_width, abs_tol=2)
+    assert math.isclose(mediabox.height, expected_height, abs_tol=2)
+
+
 def test_transformation_equivalence():
     pdf_path = RESOURCE_ROOT / "labeled-edges-center-image.pdf"
     reader_base = PdfReader(pdf_path)