Added type hints to FontFile and subclasses

Tests/test_fontfile.py

@@ -0,0 +1,12 @@
+from __future__ import annotations
+import pytest
+
+from PIL import FontFile
+
+
+def test_save(tmp_path):
+    tempname = str(tmp_path / "temp.pil")
+
+    font = FontFile.FontFile()
+    with pytest.raises(ValueError):
+        font.save(tempname)

src/PIL/BdfFontFile.py

@@ -22,6 +22,8 @@
 """
 from __future__ import annotations
 
+from typing import BinaryIO
+
 from . import FontFile, Image
 
 bdf_slant = {
@@ -36,7 +38,17 @@
 bdf_spacing = {"P": "Proportional", "M": "Monospaced", "C": "Cell"}
 
 
-def bdf_char(f):
+def bdf_char(
+    f: BinaryIO,
+) -> (
+    tuple[
+        str,
+        int,
+        tuple[tuple[int, int], tuple[int, int, int, int], tuple[int, int, int, int]],
+        Image.Image,
+    ]
+    | None
+):
     # skip to STARTCHAR
     while True:
         s = f.readline()
@@ -56,13 +68,12 @@ def bdf_char(f):
         props[s[:i].decode("ascii")] = s[i + 1 : -1].decode("ascii")
 
     # load bitmap
-    bitmap = []
+    bitmap = bytearray()
     while True:
         s = f.readline()
         if not s or s[:7] == b"ENDCHAR":
             break
-        bitmap.append(s[:-1])
-    bitmap = b"".join(bitmap)
+        bitmap += s[:-1]
 
     # The word BBX
     # followed by the width in x (BBw), height in y (BBh),
@@ -92,7 +103,7 @@ def bdf_char(f):
 class BdfFontFile(FontFile.FontFile):
     """Font file plugin for the X11 BDF format."""
 
-    def __init__(self, fp):
+    def __init__(self, fp: BinaryIO):
         super().__init__()
 
         s = fp.readline()

src/PIL/FontFile.py

@@ -16,13 +16,16 @@
 from __future__ import annotations
 
 import os
+from typing import BinaryIO
 
 from . import Image, _binary
 
 WIDTH = 800
 
 
-def puti16(fp, values):
+def puti16(
+    fp: BinaryIO, values: tuple[int, int, int, int, int, int, int, int, int, int]
+) -> None:
     """Write network order (big-endian) 16-bit sequence"""
     for v in values:
         if v < 0:
@@ -33,16 +36,34 @@ def puti16(fp, values):
 class FontFile:
     """Base class for raster font file handlers."""
 
-    bitmap = None
-
-    def __init__(self):
-        self.info = {}
-        self.glyph = [None] * 256
-
-    def __getitem__(self, ix):
+    bitmap: Image.Image | None = None
+
+    def __init__(self) -> None:
+        self.info: dict[bytes, bytes | int] = {}
+        self.glyph: list[
+            tuple[
+                tuple[int, int],
+                tuple[int, int, int, int],
+                tuple[int, int, int, int],
+                Image.Image,
+            ]
+            | None
+        ] = [None] * 256
+
+    def __getitem__(
+        self, ix: int
+    ) -> (
+        tuple[
+            tuple[int, int],
+            tuple[int, int, int, int],
+            tuple[int, int, int, int],
+            Image.Image,
+        ]
+        | None
+    ):
         return self.glyph[ix]
 
-    def compile(self):
+    def compile(self) -> None:
         """Create metrics and bitmap"""
 
         if self.bitmap:
@@ -51,7 +72,7 @@ def compile(self):
         # create bitmap large enough to hold all data
         h = w = maxwidth = 0
         lines = 1
-        for glyph in self:
+        for glyph in self.glyph:
             if glyph:
                 d, dst, src, im = glyph
                 h = max(h, src[3] - src[1])
@@ -65,13 +86,16 @@ def compile(self):
         ysize = lines * h
 
         if xsize == 0 and ysize == 0:
-            return ""
+            return
 
         self.ysize = h
 
         # paste glyphs into bitmap
         self.bitmap = Image.new("1", (xsize, ysize))
-        self.metrics = [None] * 256
+        self.metrics: list[
+            tuple[tuple[int, int], tuple[int, int, int, int], tuple[int, int, int, int]]
+            | None
+        ] = [None] * 256
         x = y = 0
         for i in range(256):
             glyph = self[i]
@@ -88,12 +112,15 @@ def compile(self):
                 self.bitmap.paste(im.crop(src), s)
                 self.metrics[i] = d, dst, s
 
-    def save(self, filename):
+    def save(self, filename: str) -> None:
         """Save font"""
 
         self.compile()
 
         # font data
+        if not self.bitmap:
+            msg = "No bitmap created"
+            raise ValueError(msg)
         self.bitmap.save(os.path.splitext(filename)[0] + ".pbm", "PNG")
 
         # font metrics
@@ -104,6 +131,6 @@ def save(self, filename):
             for id in range(256):
                 m = self.metrics[id]
                 if not m:
-                    puti16(fp, [0] * 10)
+                    puti16(fp, (0,) * 10)
                 else:
                     puti16(fp, m[0] + m[1] + m[2])

src/PIL/Image.py

@@ -1194,7 +1194,7 @@ def copy(self) -> Image:
 
     __copy__ = copy
 
-    def crop(self, box=None):
+    def crop(self, box=None) -> Image:
         """
         Returns a rectangular region from this image. The box is a
         4-tuple defining the left, upper, right, and lower pixel
@@ -1659,7 +1659,7 @@ def entropy(self, mask=None, extrema=None):
             return self.im.entropy(extrema)
         return self.im.entropy()
 
-    def paste(self, im, box=None, mask=None):
+    def paste(self, im, box=None, mask=None) -> None:
         """
         Pastes another image into this image. The box argument is either
         a 2-tuple giving the upper left corner, a 4-tuple defining the
@@ -2352,7 +2352,7 @@ def transform(x, y, matrix):
             (w, h), Transform.AFFINE, matrix, resample, fillcolor=fillcolor
         )
 
-    def save(self, fp, format=None, **params):
+    def save(self, fp, format=None, **params) -> None:
         """
         Saves this image under the given filename.  If no format is
         specified, the format to use is determined from the filename
@@ -2903,7 +2903,7 @@ def _check_size(size):
     return True
 
 
-def new(mode, size, color=0):
+def new(mode, size, color=0) -> Image:
     """
     Creates a new image with the given mode and size.
 
@@ -2942,7 +2942,7 @@ def new(mode, size, color=0):
     return im._new(core.fill(mode, size, color))
 
 
-def frombytes(mode, size, data, decoder_name="raw", *args):
+def frombytes(mode, size, data, decoder_name="raw", *args) -> Image:
     """
     Creates a copy of an image memory from pixel data in a buffer.
 

src/PIL/PcfFontFile.py

@@ -18,6 +18,7 @@
 from __future__ import annotations
 
 import io
+from typing import BinaryIO, Callable
 
 from . import FontFile, Image
 from ._binary import i8
@@ -49,7 +50,7 @@
 ]
 
 
-def sz(s, o):
+def sz(s: bytes, o: int) -> bytes:
     return s[o : s.index(b"\0", o)]
 
 
@@ -58,7 +59,7 @@ class PcfFontFile(FontFile.FontFile):
 
     name = "name"
 
-    def __init__(self, fp, charset_encoding="iso8859-1"):
+    def __init__(self, fp: BinaryIO, charset_encoding: str = "iso8859-1"):
         self.charset_encoding = charset_encoding
 
         magic = l32(fp.read(4))
@@ -104,7 +105,9 @@ def __init__(self, fp, charset_encoding="iso8859-1"):
                     bitmaps[ix],
                 )
 
-    def _getformat(self, tag):
+    def _getformat(
+        self, tag: int
+    ) -> tuple[BinaryIO, int, Callable[[bytes], int], Callable[[bytes], int]]:
         format, size, offset = self.toc[tag]
 
         fp = self.fp
@@ -119,7 +122,7 @@ def _getformat(self, tag):
 
         return fp, format, i16, i32
 
-    def _load_properties(self):
+    def _load_properties(self) -> dict[bytes, bytes | int]:
         #
         # font properties
 
@@ -138,18 +141,16 @@ def _load_properties(self):
         data = fp.read(i32(fp.read(4)))
 
         for k, s, v in p:
-            k = sz(data, k)
-            if s:
-                v = sz(data, v)
-            properties[k] = v
+            property_value: bytes | int = sz(data, v) if s else v
+            properties[sz(data, k)] = property_value
 
         return properties
 
-    def _load_metrics(self):
+    def _load_metrics(self) -> list[tuple[int, int, int, int, int, int, int, int]]:
         #
         # font metrics
 
-        metrics = []
+        metrics: list[tuple[int, int, int, int, int, int, int, int]] = []
 
         fp, format, i16, i32 = self._getformat(PCF_METRICS)
 
@@ -182,7 +183,9 @@ def _load_metrics(self):
 
         return metrics
 
-    def _load_bitmaps(self, metrics):
+    def _load_bitmaps(
+        self, metrics: list[tuple[int, int, int, int, int, int, int, int]]
+    ) -> list[Image.Image]:
         #
         # bitmap data
 
@@ -207,7 +210,7 @@ def _load_bitmaps(self, metrics):
 
         data = fp.read(bitmapsize)
 
-        pad = BYTES_PER_ROW[padindex]
+        pad: Callable[[int], int] = BYTES_PER_ROW[padindex]
         mode = "1;R"
         if bitorder:
             mode = "1"
@@ -222,7 +225,7 @@ def _load_bitmaps(self, metrics):
 
         return bitmaps
 
-    def _load_encoding(self):
+    def _load_encoding(self) -> list[int | None]:
         fp, format, i16, i32 = self._getformat(PCF_BDF_ENCODINGS)
 
         first_col, last_col = i16(fp.read(2)), i16(fp.read(2))
@@ -233,7 +236,7 @@ def _load_encoding(self):
         nencoding = (last_col - first_col + 1) * (last_row - first_row + 1)
 
         # map character code to bitmap index
-        encoding = [None] * min(256, nencoding)
+        encoding: list[int | None] = [None] * min(256, nencoding)
 
         encoding_offsets = [i16(fp.read(2)) for _ in range(nencoding)]
 

src/PIL/_binary.py

@@ -18,7 +18,7 @@
 from struct import pack, unpack_from
 
 
-def i8(c):
+def i8(c) -> int:
     return c if c.__class__ is int else c[0]
 
 
@@ -57,7 +57,7 @@ def si16be(c, o=0):
     return unpack_from(">h", c, o)[0]
 
 
-def i32le(c, o=0):
+def i32le(c, o=0) -> int:
     """
     Converts a 4-bytes (32 bits) string to an unsigned integer.
 
@@ -94,7 +94,7 @@ def o32le(i):
     return pack("<I", i)
 
 
-def o16be(i):
+def o16be(i) -> bytes:
     return pack(">H", i)