Clarify some local variable names

src/PIL/BdfFontFile.py

@@ -64,16 +64,27 @@ def bdf_char(f):
         bitmap.append(s[:-1])
     bitmap = b"".join(bitmap)
 
-    [x, y, l, d] = [int(p) for p in props["BBX"].split()]
-    [dx, dy] = [int(p) for p in props["DWIDTH"].split()]
-
-    bbox = (dx, dy), (l, -d - y, x + l, -d), (0, 0, x, y)
+    # The word BBX
+    # followed by the width in x (BBw), height in y (BBh),
+    # and x and y displacement (BBxoff0, BByoff0)
+    # of the lower left corner from the origin of the character.
+    width, height, x_disp, y_disp = [int(p) for p in props["BBX"].split()]
+
+    # The word DWIDTH
+    # followed by the width in x and y of the character in device pixels.
+    dwx, dwy = [int(p) for p in props["DWIDTH"].split()]
+
+    bbox = (
+        (dwx, dwy),
+        (x_disp, -y_disp - height, width + x_disp, -y_disp),
+        (0, 0, width, height),
+    )
 
     try:
-        im = Image.frombytes("1", (x, y), bitmap, "hex", "1")
+        im = Image.frombytes("1", (width, height), bitmap, "hex", "1")
     except ValueError:
         # deal with zero-width characters
-        im = Image.new("1", (x, y))
+        im = Image.new("1", (width, height))
 
     return id, int(props["ENCODING"]), bbox, im
 

src/PIL/Image.py

@@ -765,17 +765,17 @@ def tobytes(self, encoder_name="raw", *args):
 
         bufsize = max(65536, self.size[0] * 4)  # see RawEncode.c
 
-        data = []
+        output = []
         while True:
-            l, s, d = e.encode(bufsize)
-            data.append(d)
-            if s:
+            bytes_consumed, errcode, data = e.encode(bufsize)
+            output.append(data)
+            if errcode:
                 break
-        if s < 0:
-            msg = f"encoder error {s} in tobytes"
+        if errcode < 0:
+            msg = f"encoder error {errcode} in tobytes"
             raise RuntimeError(msg)
 
-        return b"".join(data)
+        return b"".join(output)
 
     def tobitmap(self, name="image"):
         """

src/PIL/ImageFile.py

@@ -530,20 +530,20 @@ def _encode_tile(im, fp, tile, bufsize, fh, exc=None):
             encoder.setimage(im.im, b)
             if encoder.pushes_fd:
                 encoder.setfd(fp)
-                l, s = encoder.encode_to_pyfd()
+                errcode = encoder.encode_to_pyfd()[1]
             else:
                 if exc:
                     # compress to Python file-compatible object
                     while True:
-                        l, s, d = encoder.encode(bufsize)
-                        fp.write(d)
-                        if s:
+                        errcode, data = encoder.encode(bufsize)[1:]
+                        fp.write(data)
+                        if errcode:
                             break
                 else:
                     # slight speedup: compress to real file object
-                    s = encoder.encode_to_file(fh, bufsize)
-            if s < 0:
-                msg = f"encoder error {s} when writing image file"
+                    errcode = encoder.encode_to_file(fh, bufsize)
+            if errcode < 0:
+                msg = f"encoder error {errcode} when writing image file"
                 raise OSError(msg) from exc
         finally:
             encoder.cleanup()

src/PIL/PcfFontFile.py

@@ -86,9 +86,22 @@ def __init__(self, fp, charset_encoding="iso8859-1"):
 
         for ch, ix in enumerate(encoding):
             if ix is not None:
-                x, y, l, r, w, a, d, f = metrics[ix]
-                glyph = (w, 0), (l, d - y, x + l, d), (0, 0, x, y), bitmaps[ix]
-                self.glyph[ch] = glyph
+                (
+                    xsize,
+                    ysize,
+                    left,
+                    right,
+                    width,
+                    ascent,
+                    descent,
+                    attributes,
+                ) = metrics[ix]
+                self.glyph[ch] = (
+                    (width, 0),
+                    (left, descent - ysize, xsize + left, descent),
+                    (0, 0, xsize, ysize),
+                    bitmaps[ix],
+                )
 
     def _getformat(self, tag):
         format, size, offset = self.toc[tag]
@@ -206,9 +219,11 @@ def _load_bitmaps(self, metrics):
             mode = "1"
 
         for i in range(nbitmaps):
-            x, y, l, r, w, a, d, f = metrics[i]
-            b, e = offsets[i], offsets[i + 1]
-            bitmaps.append(Image.frombytes("1", (x, y), data[b:e], "raw", mode, pad(x)))
+            xsize, ysize = metrics[i][:2]
+            b, e = offsets[i : i + 2]
+            bitmaps.append(
+                Image.frombytes("1", (xsize, ysize), data[b:e], "raw", mode, pad(xsize))
+            )
 
         return bitmaps
 

src/PIL/TiffImagePlugin.py

@@ -1845,13 +1845,13 @@ def _save(im, fp, filename):
         e.setimage(im.im, (0, 0) + im.size)
         while True:
             # undone, change to self.decodermaxblock:
-            l, s, d = e.encode(16 * 1024)
+            errcode, data = e.encode(16 * 1024)[1:]
             if not _fp:
-                fp.write(d)
-            if s:
+                fp.write(data)
+            if errcode:
                 break
-        if s < 0:
-            msg = f"encoder error {s} when writing image file"
+        if errcode < 0:
+            msg = f"encoder error {errcode} when writing image file"
             raise OSError(msg)
 
     else: