Labels does not work with categorical axis on matplotlib #4992
Description
ALL software version info
holoviews 1.14.4
jupyterlab 2.3.1
matplotlib 3.4.2
bokeh 2.3.2
Description of expected behavior and the observed behavior
Labels element raises an exception on matplotlib backend when the X axis is categorical
Complete, minimal, self-contained example code that reproduces the issue
import holoviews as hv
hv.extension('matplotlib')
hv.Labels([("hello", 12, "text")])
# This is particularly problematic for this use case
hv.Bars([('hello', 10), ('world', 20)]) * hv.Labels([("hello", 12, "text")])
Stack traceback and/or browser JavaScript console output
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
~/venv-3.9/lib/python3.9/site-packages/matplotlib/axis.py in convert_units(self, x)
1499 try:
-> 1500 ret = self.converter.convert(x, self.units, self)
1501 except Exception as e:
~/venv-3.9/lib/python3.9/site-packages/matplotlib/category.py in convert(value, unit, axis)
48 if unit is None:
---> 49 raise ValueError(
50 'Missing category information for StrCategoryConverter; '
ValueError: Missing category information for StrCategoryConverter; this might be caused by unintendedly mixing categorical and numeric data
The above exception was the direct cause of the following exception:
ConversionError Traceback (most recent call last)
~/venv-3.9/lib/python3.9/site-packages/IPython/core/formatters.py in __call__(self, obj, include, exclude)
968
969 if method is not None:
--> 970 return method(include=include, exclude=exclude)
971 return None
972 else:
~/venv-3.9/lib/python3.9/site-packages/holoviews/core/dimension.py in _repr_mimebundle_(self, include, exclude)
1315 combined and returned.
1316 """
-> 1317 return Store.render(self)
1318
1319
~/venv-3.9/lib/python3.9/site-packages/holoviews/core/options.py in render(cls, obj)
1403 data, metadata = {}, {}
1404 for hook in hooks:
-> 1405 ret = hook(obj)
1406 if ret is None:
1407 continue
~/venv-3.9/lib/python3.9/site-packages/holoviews/ipython/display_hooks.py in pprint_display(obj)
280 if not ip.display_formatter.formatters['text/plain'].pprint:
281 return None
--> 282 return display(obj, raw_output=True)
283
284
~/venv-3.9/lib/python3.9/site-packages/holoviews/ipython/display_hooks.py in display(obj, raw_output, **kwargs)
250 elif isinstance(obj, (CompositeOverlay, ViewableElement)):
251 with option_state(obj):
--> 252 output = element_display(obj)
253 elif isinstance(obj, (Layout, NdLayout, AdjointLayout)):
254 with option_state(obj):
~/venv-3.9/lib/python3.9/site-packages/holoviews/ipython/display_hooks.py in wrapped(element)
144 try:
145 max_frames = OutputSettings.options['max_frames']
--> 146 mimebundle = fn(element, max_frames=max_frames)
147 if mimebundle is None:
148 return {}, {}
~/venv-3.9/lib/python3.9/site-packages/holoviews/ipython/display_hooks.py in element_display(element, max_frames)
190 return None
191
--> 192 return render(element)
193
194
~/venv-3.9/lib/python3.9/site-packages/holoviews/ipython/display_hooks.py in render(obj, **kwargs)
66 renderer = renderer.instance(fig='png')
67
---> 68 return renderer.components(obj, **kwargs)
69
70
~/venv-3.9/lib/python3.9/site-packages/holoviews/plotting/renderer.py in components(self, obj, fmt, comm, **kwargs)
448 return data, {}
449 else:
--> 450 html = self._figure_data(plot, fmt, as_script=True, **kwargs)
451 data['text/html'] = html
452
~/venv-3.9/lib/python3.9/site-packages/holoviews/plotting/mpl/renderer.py in _figure_data(self, plot, fmt, bbox_inches, as_script, **kwargs)
173 pass
174 bytes_io = BytesIO()
--> 175 fig.canvas.print_figure(bytes_io, **kw)
176 data = bytes_io.getvalue()
177
~/venv-3.9/lib/python3.9/site-packages/matplotlib/backend_bases.py in print_figure(self, filename, dpi, facecolor, edgecolor, orientation, format, bbox_inches, pad_inches, bbox_extra_artists, backend, **kwargs)
2228 else suppress())
2229 with ctx:
-> 2230 self.figure.draw(renderer)
2231
2232 if bbox_inches:
~/venv-3.9/lib/python3.9/site-packages/matplotlib/artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
72 @wraps(draw)
73 def draw_wrapper(artist, renderer, *args, **kwargs):
---> 74 result = draw(artist, renderer, *args, **kwargs)
75 if renderer._rasterizing:
76 renderer.stop_rasterizing()
~/venv-3.9/lib/python3.9/site-packages/matplotlib/artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
49 renderer.start_filter()
50
---> 51 return draw(artist, renderer, *args, **kwargs)
52 finally:
53 if artist.get_agg_filter() is not None:
~/venv-3.9/lib/python3.9/site-packages/matplotlib/figure.py in draw(self, renderer)
2778
2779 self.patch.draw(renderer)
-> 2780 mimage._draw_list_compositing_images(
2781 renderer, self, artists, self.suppressComposite)
2782
~/venv-3.9/lib/python3.9/site-packages/matplotlib/image.py in _draw_list_compositing_images(renderer, parent, artists, suppress_composite)
130 if not_composite or not has_images:
131 for a in artists:
--> 132 a.draw(renderer)
133 else:
134 # Composite any adjacent images together
~/venv-3.9/lib/python3.9/site-packages/matplotlib/artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
49 renderer.start_filter()
50
---> 51 return draw(artist, renderer, *args, **kwargs)
52 finally:
53 if artist.get_agg_filter() is not None:
~/venv-3.9/lib/python3.9/site-packages/matplotlib/_api/deprecation.py in wrapper(*inner_args, **inner_kwargs)
429 else deprecation_addendum,
430 **kwargs)
--> 431 return func(*inner_args, **inner_kwargs)
432
433 return wrapper
~/venv-3.9/lib/python3.9/site-packages/matplotlib/axes/_base.py in draw(self, renderer, inframe)
2919 renderer.stop_rasterizing()
2920
-> 2921 mimage._draw_list_compositing_images(renderer, self, artists)
2922
2923 renderer.close_group('axes')
~/venv-3.9/lib/python3.9/site-packages/matplotlib/image.py in _draw_list_compositing_images(renderer, parent, artists, suppress_composite)
130 if not_composite or not has_images:
131 for a in artists:
--> 132 a.draw(renderer)
133 else:
134 # Composite any adjacent images together
~/venv-3.9/lib/python3.9/site-packages/matplotlib/artist.py in draw_wrapper(artist, renderer, *args, **kwargs)
49 renderer.start_filter()
50
---> 51 return draw(artist, renderer, *args, **kwargs)
52 finally:
53 if artist.get_agg_filter() is not None:
~/venv-3.9/lib/python3.9/site-packages/matplotlib/text.py in draw(self, renderer)
677
678 with _wrap_text(self) as textobj:
--> 679 bbox, info, descent = textobj._get_layout(renderer)
680 trans = textobj.get_transform()
681
~/venv-3.9/lib/python3.9/site-packages/matplotlib/text.py in _get_layout(self, renderer)
291 of a rotated text when necessary.
292 """
--> 293 key = self.get_prop_tup(renderer=renderer)
294 if key in self._cached:
295 return self._cached[key]
~/venv-3.9/lib/python3.9/site-packages/matplotlib/text.py in get_prop_tup(self, renderer)
840 need to know if the text has changed.
841 """
--> 842 x, y = self.get_unitless_position()
843 renderer = renderer or self._renderer
844 return (x, y, self.get_text(), self._color,
~/venv-3.9/lib/python3.9/site-packages/matplotlib/text.py in get_unitless_position(self)
822 # This will get the position with all unit information stripped away.
823 # This is here for convenience since it is done in several locations.
--> 824 x = float(self.convert_xunits(self._x))
825 y = float(self.convert_yunits(self._y))
826 return x, y
~/venv-3.9/lib/python3.9/site-packages/matplotlib/artist.py in convert_xunits(self, x)
201 if ax is None or ax.xaxis is None:
202 return x
--> 203 return ax.xaxis.convert_units(x)
204
205 def convert_yunits(self, y):
~/venv-3.9/lib/python3.9/site-packages/matplotlib/axis.py in convert_units(self, x)
1500 ret = self.converter.convert(x, self.units, self)
1501 except Exception as e:
-> 1502 raise munits.ConversionError('Failed to convert value(s) to axis '
1503 f'units: {x!r}') from e
1504 return ret
ConversionError: Failed to convert value(s) to axis units: 'hello'
Screenshots or screencasts of the bug in action
Works on bokeh as following, raises an exception on matplotlib:
import holoviews as hv
hv.extension('bokeh')
hv.Bars([('hello', 10), ('world', 20)]) * hv.Labels([("hello", 12, "text")])
