Fix spacing in r"$\max f$". by anntzer · Pull Request #30715 · matplotlib/matplotlib

anntzer · 2025-11-01T22:31:31Z

First commit (main implementation):

Previously, in a mathtext string like r"$\sin x$", a thin space would
(correctly) be added between "sin" and "x", but that space would be
missing in expressions like r"$\max f$". The difference arose because
of the slightly different handling of subscripts and superscripts
after the \sin and \max operators: \sin^n puts the superscript as
a normal exponent, but \max_x puts the subscript centered below the
operator name ("overunder symbol). The previous code for inserting the
thin space did not handle the "overunder" case; fix that. The new
behavior is tested by the change in test_operator_space, as well as by
mathtext1_dejavusans_06.

The change in mathtext_foo_29 arises because the extra thin space now
inserted after \limsup slightly shifts the centering of the whole
string. Ideally that thin space should be suppressed if there's no
token after the operator, but that's not something currently implemented
either for e.g. \sin (compare e.g. the right-alignments in
text(.5, .9, r"$\sin$", ha="right"); text(.5, .8, r"$\mathrm{sin}$", ha="right"); axvline(.5)
where the extra thin space after \sin is visible), so this patch just
makes things more consistent.

Second commit (cleanup):

Rename _in_subscript_or_superscript to the more descriptive
_needs_space_after_subsuper; simplify its setting in operatorname();
avoid the need to introduce an extra explicitly-typed spaced_nucleus
variable.

(See previous work in #17890 and #23243.)
@QuLogic This PR also changes a few baseline images so maybe it could get folded into the text-overhaul branch (for now I labeled it as such), but the changes are limited and standalone so it could also go in as a normal PR if that makes things simpler for you, I don't mind either way.

PR summary

PR checklist

"closes #0000" is in the body of the PR description to link the related issue
new and changed code is tested
Plotting related features are demonstrated in an example
New Features and API Changes are noted with a directive and release note
Documentation complies with general and docstring guidelines

timhoffm

LGTM, still some tests are failing.

timhoffm · 2025-11-02T12:40:37Z

lib/matplotlib/_mathtext.py

+            result = Hlist([
+                vlt,
+                *([self._make_space(self._space_widths[r'\,'])]
+                  if self._needs_space_after_subsuper else []),
+            ])
+            self._needs_space_after_subsuper = False
            return [result]


Optional alternative spelling. Choose whichever you like.

Suggested change

result = Hlist([

vlt,

*([self._make_space(self._space_widths[r'\,'])]

if self._needs_space_after_subsuper else []),

])

self._needs_space_after_subsuper = False

return [result]

spacing_nodes = (

[self._make_space(self._space_widths[r'\,'])]

if self._needs_space_after_subsuper else []

)

self._needs_space_after_subsuper = False

return [Hlist([vlt, *spacing_nodes])]

oscargus

Possibly update *_29 to include a text after? f(x)? To establish that there should be a space etc.

anntzer · 2025-11-02T21:21:22Z

Testing for the space is already provided by mathtext1_dejavusans_06 (after the max).
I'm a bit confused as to why the tests are failing given that they fail for some of the baselines that had been updated just for this purpose. Maybe resetting the target branch to main instead of text-overhaul will help? Let's try... Edit: indeed, that worked.
Also included a variant of @timhoffm's proposed change.

timhoffm

I'll leave this open, so that you can decide yourself on which branch this should go.

anntzer · 2025-11-03T00:22:09Z

Mostly that's a decision for @QuLogic, I'd say.

Previously, in a mathtext string like `r"$\sin x$"`, a thin space would (correctly) be added between "sin" and "x", but that space would be missing in expressions like `r"$\max f$"`. The difference arose because of the slightly different handling of subscripts and superscripts after the `\sin` and `\max` operators: `\sin^n` puts the superscript as a normal exponent, but `\max_x` puts the subscript centered below the operator name ("overunder symbol). The previous code for inserting the thin space did not handle the "overunder" case; fix that. The new behavior is tested by the change in test_operator_space, as well as by mathtext1_dejavusans_06. The change in mathtext_foo_29 arises because the extra thin space now inserted after `\limsup` slightly shifts the centering of the whole string. Ideally that thin space should be suppressed if there's no token after the operator, but that's not something currently implemented either for e.g. `\sin` (compare e.g. the right-alignments in `text(.5, .9, r"$\sin$", ha="right"); text(.5, .8, r"$\mathrm{sin}$", ha="right"); axvline(.5)` where the extra thin space after `\sin` is visible), so this patch just makes things more consistent.

Rename _in_subscript_or_superscript to the more descriptive _needs_space_after_subsuper; simplify its setting in operatorname(); avoid the need to introduce an extra explicitly-typed spaced_nucleus variable.

QuLogic · 2025-11-06T10:29:29Z

There shouldn't be any reason why it can't go on the text-overhaul branch...

Fix spacing in r"$\max f$".

This includes images changes for the following pull requests / commits: * [Fix center of rotation with rotation_mode='anchor'](matplotlib#29199) (c44db77) * [Remove ttconv backwards-compatibility code](matplotlib#30145) (8caff88) * [Remove kerning_factor from tests](matplotlib#29816) (7b4d725) * [Set text hinting to defaults](matplotlib#29816) (8255ae2) * [Update FreeType to 2.13.3](matplotlib#29816) (89c054d) * [Implement text shaping with libraqm](matplotlib#30000) (b0ded3a, 9813523) * [Add language parameter to Text objects](matplotlib#29794) (7ce8eae) * [Fix auto-sized glyphs with BaKoMa fonts](matplotlib#29936) (3ba2c13) * [pdf: Improve text with characters outside embedded font limits](matplotlib#30512) (b70fb88, 6cedcf7) * [Prepare `CharacterTracker` for advanced font features](matplotlib#30608) (8274e17, 70dc388, df670cf, ed5e074) * [Add font feature API to Text](matplotlib#29695) (972a688) * [Fix spacing in r"$\max f$"](matplotlib#30715) (4a99a83) * [Implement libraqm for vector outputs](matplotlib#30607) (bd17cd4) * [Drop the FT2Font intermediate buffer](matplotlib#30059) (9d7d7b4) * [Rasterize dvi files without dvipng](matplotlib#30039) (7627118) * [Update bundled FreeType and HarfBuzz libraries](matplotlib#30938) (a161658, 9619bcc) * [Fix positioning of wide mathtext accents](matplotlib#31069) (c2fa7ba) * [Refactor RendererAgg.draw_{mathtext,text,tex} to use same base algorithm](matplotlib#31085) (931bcf3) * [Implement TeX's fraction and script alignment](matplotlib#31046) (94ff452, 4bfa0f9, 1cd8510) * [Fix confusion between text height and ascent in metrics calculations](matplotlib#31107) (60f2310) * [mathtext: Fetch quad width & axis height from font metrics](matplotlib#31110) (692df3f, 383028b) * [mathtext: add mathnormal and distinguish between normal and italic family](matplotlib#31121) (a6913f3) * [ENH: Ignore empty text for tightbbox](matplotlib#31285) (d772043) * [Drop axis_artist tickdir image compat, due to text-overhaul merge](matplotlib#31281) (2057583) * [text: Use font metrics to determine line heights](matplotlib#31291) (3ab6a27, d961462, 97f4943) * [ps/pdf: Override font height metrics to support AFM files](matplotlib#31371) (e0913d4) * [TST: Cleanup back-compat code in tests touched by text overhaul](matplotlib#31295) (7c33379) * [TST: Set tests touched by text overhaul to mpl20 style](matplotlib#31300) (41c4d8d)

anntzer added this to the v3.11.0 milestone Nov 1, 2025

anntzer added the topic: text/mathtext label Nov 1, 2025

timhoffm reviewed Nov 2, 2025

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oscargus approved these changes Nov 2, 2025

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anntzer changed the base branch from text-overhaul to main November 2, 2025 21:16

anntzer force-pushed the opspace branch from feecd7c to 2ae07a5 Compare November 2, 2025 21:20

timhoffm approved these changes Nov 2, 2025

View reviewed changes

anntzer added 2 commits November 6, 2025 05:22

Tweak sub/superscript spacing implementation.

17428e3

Rename _in_subscript_or_superscript to the more descriptive _needs_space_after_subsuper; simplify its setting in operatorname(); avoid the need to introduce an extra explicitly-typed spaced_nucleus variable.

QuLogic changed the base branch from main to text-overhaul November 6, 2025 10:29

QuLogic force-pushed the opspace branch 2 times, most recently from 905fd51 to 17428e3 Compare November 6, 2025 17:26

QuLogic merged commit e952f23 into matplotlib:text-overhaul Nov 6, 2025
30 of 31 checks passed

anntzer deleted the opspace branch November 6, 2025 19:25

wavebyrd pushed a commit to wavebyrd/matplotlib that referenced this pull request Mar 13, 2026

Merge pull request matplotlib#30715 from anntzer/opspace

db12464

Fix spacing in r"$\max f$".

QuLogic mentioned this pull request Apr 10, 2026

Font and text overhaul #30161

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Fix spacing in r"$\max f$".#30715

Fix spacing in r"$\max f$".#30715
QuLogic merged 2 commits intomatplotlib:text-overhaulfrom
anntzer:opspace

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