Use class form of data classes

QuLogic · QuLogic · commit cb5cb9cbe310 · 2024-01-13T01:46:42.000-05:00
When these were added in #20118, we had no type annotations, so it made sense to use the functional form. Now that we do, there's no reason not to use the class form. Also, as `FontEntry` has gained more methods, the functional form looks less clear.
diff --git a/doc/api/font_manager_api.rst b/doc/api/font_manager_api.rst
@@ -4,6 +4,7 @@
 
 .. automodule:: matplotlib.font_manager
    :members:
+   :exclude-members: FontEntry
    :undoc-members:
    :show-inheritance:
 
diff --git a/lib/matplotlib/_text_helpers.py b/lib/matplotlib/_text_helpers.py
@@ -2,14 +2,21 @@
 Low-level text helper utilities.
 """
 
+from __future__ import annotations
+
 import dataclasses
 
 from . import _api
-from .ft2font import KERNING_DEFAULT, LOAD_NO_HINTING
+from .ft2font import KERNING_DEFAULT, LOAD_NO_HINTING, FT2Font
 
 
-LayoutItem = dataclasses.make_dataclass(
-    "LayoutItem", ["ft_object", "char", "glyph_idx", "x", "prev_kern"])
+@dataclasses.dataclass(frozen=True)
+class LayoutItem:
+    ft_object: FT2Font
+    char: str
+    glyph_idx: int
+    x: float
+    prev_kern: float
 
 
 def warn_on_missing_glyph(codepoint, fontnames):
@@ -38,9 +45,10 @@ def warn_on_missing_glyph(codepoint, fontnames):
 
 def layout(string, font, *, kern_mode=KERNING_DEFAULT):
     """
-    Render *string* with *font*.  For each character in *string*, yield a
-    (glyph-index, x-position) pair.  When such a pair is yielded, the font's
-    glyph is set to the corresponding character.
+    Render *string* with *font*.
+
+    For each character in *string*, yield a LayoutItem instance. When such an instance
+    is yielded, the font's glyph is set to the corresponding character.
 
     Parameters
     ----------
@@ -53,8 +61,7 @@ def layout(string, font, *, kern_mode=KERNING_DEFAULT):
 
     Yields
     ------
-    glyph_index : int
-    x_position : float
+    LayoutItem
     """
     x = 0
     prev_glyph_idx = None
diff --git a/lib/matplotlib/backends/backend_pdf.py b/lib/matplotlib/backends/backend_pdf.py
@@ -2378,8 +2378,7 @@ def draw_text(self, gc, x, y, s, prop, angle, ismath=False, mtext=None):
             multibyte_glyphs = []
             prev_was_multibyte = True
             prev_font = font
-            for item in _text_helpers.layout(
-                    s, font, kern_mode=KERNING_UNFITTED):
+            for item in _text_helpers.layout(s, font, kern_mode=KERNING_UNFITTED):
                 if _font_supports_glyph(fonttype, ord(item.char)):
                     if prev_was_multibyte or item.ft_object != prev_font:
                         singlebyte_chunks.append((item.ft_object, item.x, []))
@@ -2389,9 +2388,7 @@ def draw_text(self, gc, x, y, s, prop, angle, ismath=False, mtext=None):
                     singlebyte_chunks[-1][2].append(item.char)
                     prev_was_multibyte = False
                 else:
-                    multibyte_glyphs.append(
-                        (item.ft_object, item.x, item.glyph_idx)
-                    )
+                    multibyte_glyphs.append((item.ft_object, item.x, item.glyph_idx))
                     prev_was_multibyte = True
             # Do the rotation and global translation as a single matrix
             # concatenation up front
diff --git a/lib/matplotlib/font_manager.py b/lib/matplotlib/font_manager.py
@@ -25,6 +25,8 @@
 #   - setWeights function needs improvement
 #   - 'light' is an invalid weight value, remove it.
 
+from __future__ import annotations
+
 from base64 import b64encode
 from collections import namedtuple
 import copy
@@ -41,7 +43,6 @@
 import subprocess
 import sys
 import threading
-from typing import Union
 
 import matplotlib as mpl
 from matplotlib import _api, _afm, cbook, ft2font
@@ -304,42 +305,35 @@ def findSystemFonts(fontpaths=None, fontext='ttf'):
     return [fname for fname in fontfiles if os.path.exists(fname)]
 
 
-def _fontentry_helper_repr_png(fontent):
-    from matplotlib.figure import Figure  # Circular import.
-    fig = Figure()
-    font_path = Path(fontent.fname) if fontent.fname != '' else None
-    fig.text(0, 0, fontent.name, font=font_path)
-    with BytesIO() as buf:
-        fig.savefig(buf, bbox_inches='tight', transparent=True)
-        return buf.getvalue()
-
-
-def _fontentry_helper_repr_html(fontent):
-    png_stream = _fontentry_helper_repr_png(fontent)
-    png_b64 = b64encode(png_stream).decode()
-    return f"<img src=\"data:image/png;base64, {png_b64}\" />"
-
-
-FontEntry = dataclasses.make_dataclass(
-    'FontEntry', [
-        ('fname', str, dataclasses.field(default='')),
-        ('name', str, dataclasses.field(default='')),
-        ('style', str, dataclasses.field(default='normal')),
-        ('variant', str, dataclasses.field(default='normal')),
-        ('weight', Union[str, int], dataclasses.field(default='normal')),
-        ('stretch', str, dataclasses.field(default='normal')),
-        ('size', str, dataclasses.field(default='medium')),
-    ],
-    namespace={
-        '__doc__': """
+@dataclasses.dataclass(frozen=True)
+class FontEntry:
+    """
     A class for storing Font properties.
 
     It is used when populating the font lookup dictionary.
-    """,
-        '_repr_html_': lambda self: _fontentry_helper_repr_html(self),
-        '_repr_png_': lambda self: _fontentry_helper_repr_png(self),
-    }
-)
+    """
+
+    fname: str = ''
+    name: str = ''
+    style: str = 'normal'
+    variant: str = 'normal'
+    weight: str | int = 'normal'
+    stretch: str = 'normal'
+    size: str = 'medium'
+
+    def _repr_html_(self) -> str:
+        png_stream = self._repr_png_()
+        png_b64 = b64encode(png_stream).decode()
+        return f"<img src=\"data:image/png;base64, {png_b64}\" />"
+
+    def _repr_png_(self) -> bytes:
+        from matplotlib.figure import Figure  # Circular import.
+        fig = Figure()
+        font_path = Path(self.fname) if self.fname != '' else None
+        fig.text(0, 0, self.name, font=font_path)
+        with BytesIO() as buf:
+            fig.savefig(buf, bbox_inches='tight', transparent=True)
+            return buf.getvalue()
 
 
 def ttfFontProperty(font):
@@ -926,8 +920,7 @@ def default(self, o):
             try:
                 # Cache paths of fonts shipped with Matplotlib relative to the
                 # Matplotlib data path, which helps in the presence of venvs.
-                d["fname"] = str(
-                    Path(d["fname"]).relative_to(mpl.get_data_path()))
+                d["fname"] = str(Path(d["fname"]).relative_to(mpl.get_data_path()))
             except ValueError:
                 pass
             return d
@@ -944,10 +937,9 @@ def _json_decode(o):
         r.__dict__.update(o)
         return r
     elif cls == 'FontEntry':
-        r = FontEntry.__new__(FontEntry)
-        r.__dict__.update(o)
-        if not os.path.isabs(r.fname):
-            r.fname = os.path.join(mpl.get_data_path(), r.fname)
+        if not os.path.isabs(o['fname']):
+            o['fname'] = os.path.join(mpl.get_data_path(), o['fname'])
+        r = FontEntry(**o)
         return r
     else:
         raise ValueError("Don't know how to deserialize __class__=%s" % cls)
