Using ultraplot to plot and display errors

[lixuan-code]

System details: Windows 11

Positron and OS details:

Positron Version: 2025.12.1 (user setup) build 4
Code - OSS Version: 1.106.0
Commit: f70a9bc
Date: 2025-12-05T21:10:23.935Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Windows_NT x64 10.0.26200

Python 3.11.9

Describe the issue:

As you can see, when I was using Ultraplot to plot, the following error occurred in the plot area. When I tried other image options, it still had the same error.

Error rendering plot to 'Matplotlib (4in×3.5in)' size: Internal error: Method locally_modified_subplot_params() is disabled on ultraplot gridspecs. (-32603)

[timtmok]

Thank you for opening this issue! I'll add some more details to help reproduce this.

Simple reprex:

import ultraplot as uplt

fig = uplt.figure(space=0, refwidth="10em")
axs = fig.subplots(nrows=3, ncols=3)

When creating the subplots, it goes into an infinite plot render loop. This is one of the tracebacks:

Error in callback <function _draw_all_if_interactive at 0x1165d67a0> (for post_execute), with arguments args (),kwargs {}:
RuntimeError: Method locally_modified_subplot_params() is disabled on ultraplot gridspecs.
File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/matplotlib/pyplot.py:279, in _draw_all_if_interactive()
    277 def _draw_all_if_interactive() -> None:
    278     if matplotlib.is_interactive():
--> 279         draw_all()
Hide Traceback
Fix
Explain
File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/matplotlib/_pylab_helpers.py:131, in Gcf.draw_all(cls, force)
    129 for manager in cls.get_all_fig_managers():
    130     if force or manager.canvas.figure.stale:
--> 131         manager.canvas.draw_idle()

File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/matplotlib/backend_bases.py:1893, in FigureCanvasBase.draw_idle(self, *args, **kwargs)
   1891 if not self._is_idle_drawing:
   1892     with self._idle_draw_cntx():
-> 1893         self.draw(*args, **kwargs)

File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/ultraplot/figure.py:479, in _add_canvas_preprocessor.<locals>._canvas_preprocess(self, *args, **kwargs)
    477 with ctx1, ctx2, ctx3:
    478     fig.auto_layout()
--> 479     return func(self, *args, **kwargs)

File /Applications/Positron.app/Contents/Resources/app/extensions/positron-python/python_files/posit/positron/matplotlib_backend.py:133, in FigureCanvasPositron.draw(self, is_rendering)
    131 logger.debug("Drawing to canvas")
    132 try:
--> 133     super().draw()
    134 finally:
    135     # Do nothing if the canvas has not been rendered yet, to avoid an unnecessary update
    136     # since opening the comm will trigger a render from the frontend.
    137     if not self._first_render_completed:

File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/matplotlib/backends/backend_agg.py:382, in FigureCanvasAgg.draw(self)
    379 # Acquire a lock on the shared font cache.
    380 with (self.toolbar._wait_cursor_for_draw_cm() if self.toolbar
    381       else nullcontext()):
--> 382     self.figure.draw(self.renderer)
    383     # A GUI class may be need to update a window using this draw, so
    384     # don't forget to call the superclass.
    385     super().draw()

File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/matplotlib/artist.py:38, in _prevent_rasterization.<locals>.draw_wrapper(artist, renderer, *args, **kwargs)
     35     renderer.stop_rasterizing()
     36     renderer._rasterizing = False
---> 38 return draw(artist, renderer, *args, **kwargs)

File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/ultraplot/figure.py:835, in Figure.draw(self, renderer)
    833 self._share_ticklabels(axis="x")
    834 self._share_ticklabels(axis="y")
--> 835 super().draw(renderer)

File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/matplotlib/artist.py:94, in _finalize_rasterization.<locals>.draw_wrapper(artist, renderer, *args, **kwargs)
     92 @wraps(draw)
     93 def draw_wrapper(artist, renderer, *args, **kwargs):
---> 94     result = draw(artist, renderer, *args, **kwargs)
     95     if renderer._rasterizing:
     96         renderer.stop_rasterizing()

File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/matplotlib/artist.py:71, in allow_rasterization.<locals>.draw_wrapper(artist, renderer)
     68     if artist.get_agg_filter() is not None:
     69         renderer.start_filter()
---> 71     return draw(artist, renderer)
     72 finally:
     73     if artist.get_agg_filter() is not None:

File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/matplotlib/figure.py:3251, in Figure.draw(self, renderer)
   3249 if self.axes and self.get_layout_engine() is not None:
   3250     try:
-> 3251         self.get_layout_engine().execute(self)
   3252     except ValueError:
   3253         pass

File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/matplotlib/layout_engine.py:189, in TightLayoutEngine.execute(self, fig)
    186 renderer = fig._get_renderer()
    187 with getattr(renderer, "_draw_disabled", nullcontext)():
    188     kwargs = get_tight_layout_figure(
--> 189         fig, fig.axes, get_subplotspec_list(fig.axes), renderer,
    190         pad=info['pad'], h_pad=info['h_pad'], w_pad=info['w_pad'],
    191         rect=info['rect'])
    192 if kwargs:
    193     fig.subplots_adjust(**kwargs)

File ~/.pyenv/versions/3.12.9/lib/python3.12/site-packages/matplotlib/_tight_layout.py:184, in get_subplotspec_list(axes_list, grid_spec)
    182             if gs != grid_spec:
    183                 subplotspec = None
--> 184         elif gs.locally_modified_subplot_params():
    185             subplotspec = None
    186 else: