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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Cartopy axes_grid_basic example broken by Matplotlib 3.6","articleBody":"Cartopy's [axes_grid_basic](https://scitools.org.uk/cartopy/docs/latest/gallery/miscellanea/axes_grid_basic.html) was broken by Matplotlib 3.6. The relevant call is:\r\n```python\r\n    axgr = AxesGrid(fig, 111, axes_class=axes_class,\r\n                    nrows_ncols=(3, 2),\r\n                    axes_pad=0.6,\r\n                    cbar_location='right',\r\n                    cbar_mode='single',\r\n                    cbar_pad=0.2,\r\n                    cbar_size='3%',\r\n                    label_mode='')  # note the empty label_mode\r\n```\r\n\r\nIn #23550, we began explicitly checking for the documented values of `label_mode`, (`'All', 'L', '1'`), which this runs afoul of. It appears the previous code let `''` (or any option not handled) essentially work as a noop for `set_label_mode()`.\r\n\r\nBased on the output when the example worked, `'1'` would be fine behavior-wise, but that currently produces in this example:\r\n```pytb\r\n/Users/rmay/repos/cartopy/examples/miscellanea/axes_grid_basic.py:48: MatplotlibDeprecationWarning: The resize_event function was deprecated in Matplotlib 3.6 and will be removed two minor releases later. Use callbacks.process('resize_event', ResizeEvent(...)) instead.\r\n  fig = plt.figure()\r\nTraceback (most recent call last):\r\n  File \"/Users/rmay/repos/cartopy/examples/miscellanea/axes_grid_basic.py\", line 78, in \u003cmodule\u003e\r\n    main()\r\n  File \"/Users/rmay/repos/cartopy/examples/miscellanea/axes_grid_basic.py\", line 49, in main\r\n    axgr = AxesGrid(fig, 111,\r\n  File \"/Users/rmay/miniconda3/envs/py310/lib/python3.10/site-packages/mpl_toolkits/axes_grid1/axes_grid.py\", line 391, in __init__\r\n    super().__init__(\r\n  File \"/Users/rmay/miniconda3/envs/py310/lib/python3.10/site-packages/mpl_toolkits/axes_grid1/axes_grid.py\", line 174, in __init__\r\n    self.set_label_mode(label_mode)\r\n  File \"/Users/rmay/miniconda3/envs/py310/lib/python3.10/site-packages/mpl_toolkits/axes_grid1/axes_grid.py\", line 295, in set_label_mode\r\n    _tick_only(ax, bottom_on=True, left_on=True)\r\n  File \"/Users/rmay/miniconda3/envs/py310/lib/python3.10/site-packages/mpl_toolkits/axes_grid1/axes_grid.py\", line 16, in _tick_only\r\n    ax.axis[\"bottom\"].toggle(ticklabels=bottom_off, label=bottom_off)\r\nTypeError: 'method' object is not subscriptable\r\n```\r\n\r\nThis is because, while `AxesGrid` supposedly supports arbitrary classes by passing `axes_class`, there's a huge caveat: the default is `mpl_toolkits.axes_grid1.mpl_axes.Axes` (TERRIBLY CONFUSING NAME--it's imported as just `Axes` in `axis_grid.py`). This is a custom subclass that adds:\r\n\r\n```python\r\n    @property\r\n    def axis(self):\r\n        return self._axislines\r\n\r\n    def clear(self):\r\n        # docstring inherited\r\n        super().clear()\r\n        # Init axis artists.\r\n        self._axislines = self.AxisDict(self)\r\n        self._axislines.update(\r\n            bottom=SimpleAxisArtist(self.xaxis, 1, self.spines[\"bottom\"]),\r\n            top=SimpleAxisArtist(self.xaxis, 2, self.spines[\"top\"]),\r\n            left=SimpleAxisArtist(self.yaxis, 1, self.spines[\"left\"]),\r\n            right=SimpleAxisArtist(self.yaxis, 2, self.spines[\"right\"]))\r\n```\r\n\r\nOptions I can think of:\r\n1. Restore a noop option for `set_label_mode`\r\n2. Fix `AxesGrid` to work more generally with `axes_class`--monkey-patch/subclass to add the necessary modifications\r\n3. Document that `axes_class` needs to have certain behavior\r\n4. Fix `AxesGrid` to not rely on a property that OVERRIDES `matplotlib.axes.Axes.axis` with a *different type* that also manually dispatches to the unbound `axis()` method :scream: \r\n```python\r\n    class AxisDict(dict):\r\n        def __init__(self, axes):\r\n            self.axes = axes\r\n            super().__init__()\r\n\r\n        def __getitem__(self, k):\r\n            if isinstance(k, tuple):\r\n                r = SimpleChainedObjects(\r\n                    # super() within a list comprehension needs explicit args.\r\n                    [super(Axes.AxisDict, self).__getitem__(k1) for k1 in k])\r\n                return r\r\n            elif isinstance(k, slice):\r\n                if k.start is None and k.stop is None and k.step is None:\r\n                    return SimpleChainedObjects(list(self.values()))\r\n                else:\r\n                    raise ValueError(\"Unsupported slice\")\r\n            else:\r\n                return dict.__getitem__(self, k)\r\n\r\n        def __call__(self, *v, **kwargs):\r\n            return maxes.Axes.axis(self.axes, *v, **kwargs)\r\n```\r\n\r\nAnyone have any opinions?","author":{"url":"https://github.com/dopplershift","@type":"Person","name":"dopplershift"},"datePublished":"2022-09-29T18:46:21.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":15},"url":"https://github.com/24053/matplotlib/issues/24053"}