From eec859384186b0210f3e6e6abcd42f40ed2e9b12 Mon Sep 17 00:00:00 2001
From: Antony Lee <anntzer.lee@gmail.com>
Date: Sat, 26 Apr 2025 23:22:50 +0200
Subject: [PATCH] Improve repr of mathtext internal structures; minor cleanup.

- Improve the repr of mathtext boxes (see test_box_repr; previously the
  entire repr would be in a single line).  Boxes are internal objects
  not exposed by any public API so the change is purely for debugging
  purposes.
- In ship, off_h and off_v are never modified, so there's no need to
  declare them as nonlocal in the nested functions.
---
 lib/matplotlib/_mathtext.py           | 15 ++++++---
 lib/matplotlib/tests/test_mathtext.py | 44 +++++++++++++++++++++++++--
 2 files changed, 52 insertions(+), 7 deletions(-)

diff --git a/lib/matplotlib/_mathtext.py b/lib/matplotlib/_mathtext.py
index ae230703faed..3739a517978b 100644
--- a/lib/matplotlib/_mathtext.py
+++ b/lib/matplotlib/_mathtext.py
@@ -14,6 +14,7 @@
 import types
 import unicodedata
 import string
+import textwrap
 import typing as T
 from typing import NamedTuple
 
@@ -1165,12 +1166,16 @@ def __init__(self, elements: T.Sequence[Node]):
         self.glue_sign    = 0    # 0: normal, -1: shrinking, 1: stretching
         self.glue_order   = 0    # The order of infinity (0 - 3) for the glue
 
-    def __repr__(self) -> str:
-        return '{}<w={:.02f} h={:.02f} d={:.02f} s={:.02f}>[{}]'.format(
+    def __repr__(self):
+        return "{}<w={:.02f} h={:.02f} d={:.02f} s={:.02f}>[{}]".format(
             super().__repr__(),
             self.width, self.height,
             self.depth, self.shift_amount,
-            ', '.join([repr(x) for x in self.children]))
+            "\n" + textwrap.indent(
+                "\n".join(map("{!r},".format, self.children)),
+                "  ") + "\n"
+            if self.children else ""
+        )
 
     def _set_glue(self, x: float, sign: int, totals: list[float],
                   error_type: str) -> None:
@@ -1604,7 +1609,7 @@ def clamp(value: float) -> float:
         return -1e9 if value < -1e9 else +1e9 if value > +1e9 else value
 
     def hlist_out(box: Hlist) -> None:
-        nonlocal cur_v, cur_h, off_h, off_v
+        nonlocal cur_v, cur_h
 
         cur_g = 0
         cur_glue = 0.
@@ -1667,7 +1672,7 @@ def hlist_out(box: Hlist) -> None:
                 cur_h += rule_width
 
     def vlist_out(box: Vlist) -> None:
-        nonlocal cur_v, cur_h, off_h, off_v
+        nonlocal cur_v, cur_h
 
         cur_g = 0
         cur_glue = 0.
diff --git a/lib/matplotlib/tests/test_mathtext.py b/lib/matplotlib/tests/test_mathtext.py
index 9c0f8ee70c1f..198e640ad286 100644
--- a/lib/matplotlib/tests/test_mathtext.py
+++ b/lib/matplotlib/tests/test_mathtext.py
@@ -4,8 +4,9 @@
 from pathlib import Path
 import platform
 import re
-from xml.etree import ElementTree as ET
+import textwrap
 from typing import Any
+from xml.etree import ElementTree as ET
 
 import numpy as np
 from packaging.version import parse as parse_version
@@ -16,7 +17,8 @@
 import matplotlib as mpl
 from matplotlib.testing.decorators import check_figures_equal, image_comparison
 import matplotlib.pyplot as plt
-from matplotlib import mathtext, _mathtext
+from matplotlib import font_manager as fm, mathtext, _mathtext
+from matplotlib.ft2font import LoadFlags
 
 pyparsing_version = parse_version(pyparsing.__version__)
 
@@ -558,3 +560,41 @@ def test_mathtext_operators():
 def test_boldsymbol(fig_test, fig_ref):
     fig_test.text(0.1, 0.2, r"$\boldsymbol{\mathrm{abc0123\alpha}}$")
     fig_ref.text(0.1, 0.2, r"$\mathrm{abc0123\alpha}$")
+
+
+def test_box_repr():
+    s = repr(_mathtext.Parser().parse(
+        r"$\frac{1}{2}$",
+        _mathtext.DejaVuSansFonts(fm.FontProperties(), LoadFlags.NO_HINTING),
+        fontsize=12, dpi=100))
+    assert s == textwrap.dedent("""\
+        Hlist<w=9.49 h=16.08 d=6.64 s=0.00>[
+          Hlist<w=0.00 h=0.00 d=0.00 s=0.00>[],
+          Hlist<w=9.49 h=16.08 d=6.64 s=0.00>[
+            Hlist<w=9.49 h=16.08 d=6.64 s=0.00>[
+              Vlist<w=7.40 h=22.72 d=0.00 s=6.64>[
+                HCentered<w=7.40 h=8.67 d=0.00 s=0.00>[
+                  Glue,
+                  Hlist<w=7.40 h=8.67 d=0.00 s=0.00>[
+                    `1`,
+                    k2.36,
+                  ],
+                  Glue,
+                ],
+                Vbox,
+                Hrule,
+                Vbox,
+                HCentered<w=7.40 h=8.84 d=0.00 s=0.00>[
+                  Glue,
+                  Hlist<w=7.40 h=8.84 d=0.00 s=0.00>[
+                    `2`,
+                    k2.02,
+                  ],
+                  Glue,
+                ],
+              ],
+              Hbox,
+            ],
+          ],
+          Hlist<w=0.00 h=0.00 d=0.00 s=0.00>[],
+        ]""")