Bug report

Bug summary

All's in the title.

Code for reproduction

frompylabimport*figtext(.5,.5,r"$\widebar{abc} \qquad \mathrm{\widebar{abc}}$")

Actual outcome

Expected outcome

The bar should be correctly centered. (The italic version is still ok-ish, but the roman one is far too offset.)
Likewise for\widehat and\widetilde.

Matplotlib version

• Operating system: linux
• Matplotlib version (import matplotlib; print(matplotlib.__version__)): HEAD (3.3+)
• Matplotlib backend (print(matplotlib.get_backend())): qt5agg
• Python version: 3.9
• Jupyter version (if applicable):
• Other libraries:

From a quick look, this is due to thesym.width/4 horizontal correction added to an HCentered box inaccent(). Indeed replacingcentered by justaccent_box appears to fix the issue... but now the italic correction is lost when using italics.

I think the correct solution likely implies doing an exegesis of node 12 of the TeXbook's appendix G (p442), or any of the articles linked at#18916 (comment).