Fix #3548: Match MathTex subscripts/superscripts by position

manim/mobject/text/tex_mobject.py

@@ -31,6 +31,7 @@
 from textwrap import dedent
 from typing import Any
 
+import numpy as np
 from typing_extensions import Self
 
 from manim import config, logger
@@ -356,7 +357,25 @@ def _break_up_by_substrings(self) -> Self:
                 last_submob_index = min(curr_index, len(self.submobjects) - 1)
                 sub_tex_mob.move_to(self.submobjects[last_submob_index], RIGHT)
             else:
-                sub_tex_mob.submobjects = self.submobjects[curr_index:new_index]
+                is_script = tex_string.strip().startswith(("^", "_"))
+                remaining = self.submobjects[curr_index:new_index]
+
+                if is_script and len(remaining) >= num_submobs:
+                    matched_submobs = []
+                    for target_submob in sub_tex_mob.submobjects:
+                        if not remaining:
+                            break
+                        target_center = target_submob.get_center()
+                        best_match_idx = min(
+                            range(len(remaining)),
+                            key=lambda i: np.linalg.norm(
+                                remaining[i].get_center() - target_center
+                            ),
+                        )
+                        matched_submobs.append(remaining.pop(best_match_idx))
+                    sub_tex_mob.submobjects = matched_submobs
+                else:
+                    sub_tex_mob.submobjects = self.submobjects[curr_index:new_index]
             new_submobjects.append(sub_tex_mob)
             curr_index = new_index
         self.submobjects = new_submobjects

tests/module/mobject/text/test_texmobject.py

@@ -225,3 +225,31 @@ def test_tex_garbage_collection(tmpdir, monkeypatch, config):
 
     tex_with_log = Tex("Hello World, again!")  # da27670a37b08799.tex
     assert Path("media", "Tex", "da27670a37b08799.log").exists()
+
+
+def test_tex_strings_with_subscripts_and_superscripts():
+    """Check that MathTex submobjects match their tex_strings when using
+    subscripts and superscripts in different orders.
+
+    This is a regression test for issue #3548. LaTeX may reorder subscripts
+    and superscripts in the compiled output, but the submobjects should still
+    correspond to their original tex_strings.
+    """
+    # Test with superscript before subscript
+    eq1 = MathTex("A", "^n", "_1")
+    assert eq1.submobjects[0].get_tex_string() == "A"
+    assert eq1.submobjects[1].get_tex_string() == "^n"
+    assert eq1.submobjects[2].get_tex_string() == "_1"
+
+    # Test with subscript before superscript (reversed order)
+    eq2 = MathTex("A", "_1", "^n")
+    assert eq2.submobjects[0].get_tex_string() == "A"
+    assert eq2.submobjects[1].get_tex_string() == "_1"
+    assert eq2.submobjects[2].get_tex_string() == "^n"
+
+    # Test with summation and multiple terms
+    eq3 = MathTex("\\sum", "^n", "_1", "x")
+    assert eq3.submobjects[0].get_tex_string() == "\\sum"
+    assert eq3.submobjects[1].get_tex_string() == "^n"
+    assert eq3.submobjects[2].get_tex_string() == "_1"
+    assert eq3.submobjects[3].get_tex_string() == "x"