Added type hints

pyproject.toml

@@ -146,7 +146,6 @@ exclude = [
   '^src/PIL/DdsImagePlugin.py$',
   '^src/PIL/FpxImagePlugin.py$',
   '^src/PIL/Image.py$',
-  '^src/PIL/ImageMorph.py$',
   '^src/PIL/ImageQt.py$',
   '^src/PIL/ImageShow.py$',
   '^src/PIL/ImImagePlugin.py$',

src/PIL/ImageMorph.py

@@ -62,12 +62,14 @@ class LutBuilder:
 
     """
 
-    def __init__(self, patterns=None, op_name=None):
+    def __init__(
+        self, patterns: list[str] | None = None, op_name: str | None = None
+    ) -> None:
         if patterns is not None:
             self.patterns = patterns
         else:
             self.patterns = []
-        self.lut = None
+        self.lut: bytearray | None = None
         if op_name is not None:
             known_patterns = {
                 "corner": ["1:(... ... ...)->0", "4:(00. 01. ...)->1"],
@@ -87,25 +89,27 @@ class LutBuilder:
 
             self.patterns = known_patterns[op_name]
 
-    def add_patterns(self, patterns):
+    def add_patterns(self, patterns: list[str]) -> None:
         self.patterns += patterns
 
-    def build_default_lut(self):
+    def build_default_lut(self) -> None:
         symbols = [0, 1]
         m = 1 << 4  # pos of current pixel
         self.lut = bytearray(symbols[(i & m) > 0] for i in range(LUT_SIZE))
 
-    def get_lut(self):
+    def get_lut(self) -> bytearray | None:
         return self.lut
 
-    def _string_permute(self, pattern, permutation):
+    def _string_permute(self, pattern: str, permutation: list[int]) -> str:
         """string_permute takes a pattern and a permutation and returns the
         string permuted according to the permutation list.
         """
         assert len(permutation) == 9
         return "".join(pattern[p] for p in permutation)
 
-    def _pattern_permute(self, basic_pattern, options, basic_result):
+    def _pattern_permute(
+        self, basic_pattern: str, options: str, basic_result: int
+    ) -> list[tuple[str, int]]:
         """pattern_permute takes a basic pattern and its result and clones
         the pattern according to the modifications described in the $options
         parameter. It returns a list of all cloned patterns."""
@@ -135,12 +139,13 @@ class LutBuilder:
 
         return patterns
 
-    def build_lut(self):
+    def build_lut(self) -> bytearray:
         """Compile all patterns into a morphology lut.
 
         TBD :Build based on (file) morphlut:modify_lut
         """
         self.build_default_lut()
+        assert self.lut is not None
         patterns = []
 
         # Parse and create symmetries of the patterns strings
@@ -159,10 +164,10 @@ class LutBuilder:
             patterns += self._pattern_permute(pattern, options, result)
 
         # compile the patterns into regular expressions for speed
-        for i, pattern in enumerate(patterns):
+        compiled_patterns = []
+        for pattern in patterns:
             p = pattern[0].replace(".", "X").replace("X", "[01]")
-            p = re.compile(p)
-            patterns[i] = (p, pattern[1])
+            compiled_patterns.append((re.compile(p), pattern[1]))
 
         # Step through table and find patterns that match.
         # Note that all the patterns are searched. The last one
@@ -172,8 +177,8 @@ class LutBuilder:
             bitpattern = bin(i)[2:]
             bitpattern = ("0" * (9 - len(bitpattern)) + bitpattern)[::-1]
 
-            for p, r in patterns:
-                if p.match(bitpattern):
+            for pattern, r in compiled_patterns:
+                if pattern.match(bitpattern):
                     self.lut[i] = [0, 1][r]
 
         return self.lut
@@ -182,7 +187,12 @@ class LutBuilder:
 class MorphOp:
     """A class for binary morphological operators"""
 
-    def __init__(self, lut=None, op_name=None, patterns=None):
+    def __init__(
+        self,
+        lut: bytearray | None = None,
+        op_name: str | None = None,
+        patterns: list[str] | None = None,
+    ) -> None:
         """Create a binary morphological operator"""
         self.lut = lut
         if op_name is not None:
@@ -190,7 +200,7 @@ class MorphOp:
         elif patterns is not None:
             self.lut = LutBuilder(patterns=patterns).build_lut()
 
-    def apply(self, image):
+    def apply(self, image: Image.Image):
         """Run a single morphological operation on an image
 
         Returns a tuple of the number of changed pixels and the
@@ -206,7 +216,7 @@ class MorphOp:
         count = _imagingmorph.apply(bytes(self.lut), image.im.id, outimage.im.id)
         return count, outimage
 
-    def match(self, image):
+    def match(self, image: Image.Image):
         """Get a list of coordinates matching the morphological operation on
         an image.
 
@@ -221,7 +231,7 @@ class MorphOp:
             raise ValueError(msg)
         return _imagingmorph.match(bytes(self.lut), image.im.id)
 
-    def get_on_pixels(self, image):
+    def get_on_pixels(self, image: Image.Image):
         """Get a list of all turned on pixels in a binary image
 
         Returns a list of tuples of (x,y) coordinates
@@ -232,7 +242,7 @@ class MorphOp:
             raise ValueError(msg)
         return _imagingmorph.get_on_pixels(image.im.id)
 
-    def load_lut(self, filename):
+    def load_lut(self, filename: str) -> None:
         """Load an operator from an mrl file"""
         with open(filename, "rb") as f:
             self.lut = bytearray(f.read())
@@ -242,7 +252,7 @@ class MorphOp:
             msg = "Wrong size operator file!"
             raise Exception(msg)
 
-    def save_lut(self, filename):
+    def save_lut(self, filename: str) -> None:
         """Save an operator to an mrl file"""
         if self.lut is None:
             msg = "No operator loaded"
@@ -250,6 +260,6 @@ class MorphOp:
         with open(filename, "wb") as f:
             f.write(self.lut)
 
-    def set_lut(self, lut):
+    def set_lut(self, lut: bytearray | None) -> None:
         """Set the lut from an external source"""
         self.lut = lut

src/PIL/_imagingmorph.pyi

@@ -0,0 +1,5 @@
+from __future__ import annotations
+
+from typing import Any
+
+def __getattr__(name: str) -> Any: ...