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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"BUG: TypeError in plt.savefig using cairo backend","articleBody":"Saving a figure with `plt.savefig` in `svg` file format using the `cairo` backend results in a `TypeError`. The Traceback is:\r\n\r\n```\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/util/plot.py\", line 814, in save_and_close_fig\r\n    plt.savefig('plot.svg', transparent=True, dpi=800)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/pyplot.py\", line 689, in savefig\r\n    res = fig.savefig(*args, **kwargs)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/figure.py\", line 2094, in savefig\r\n    self.canvas.print_figure(fname, **kwargs)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/backend_bases.py\", line 2075, in print_figure\r\n    **kwargs)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/backends/backend_cairo.py\", line 569, in print_svg\r\n    return self._save(fobj, 'svg', *args, **kwargs)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/backends/backend_cairo.py\", line 622, in _save\r\n    self.figure.draw(renderer)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/artist.py\", line 50, in draw_wrapper\r\n    return draw(artist, renderer, *args, **kwargs)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/figure.py\", line 1649, in draw\r\n    renderer, self, artists, self.suppressComposite)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/image.py\", line 138, in _draw_list_compositing_images\r\n    a.draw(renderer)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/artist.py\", line 50, in draw_wrapper\r\n    return draw(artist, renderer, *args, **kwargs)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/axes/_base.py\", line 2628, in draw\r\n    mimage._draw_list_compositing_images(renderer, self, artists)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/image.py\", line 138, in _draw_list_compositing_images\r\n    a.draw(renderer)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/artist.py\", line 50, in draw_wrapper\r\n    return draw(artist, renderer, *args, **kwargs)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/axis.py\", line 1185, in draw\r\n    ticks_to_draw = self._update_ticks(renderer)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/axis.py\", line 1023, in _update_ticks\r\n    tick_tups = list(self.iter_ticks())  # iter_ticks calls the locator\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/axis.py\", line 967, in iter_ticks\r\n    majorLocs = self.major.locator()\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/ticker.py\", line 2128, in __call__\r\n    return self.tick_values(vmin, vmax)\r\n  File \"/sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/ticker.py\", line 2189, in tick_values\r\n    have_subs = len(subs) \u003e 1 or (len(subs == 1) and subs[0] != 1.0)\r\nTypeError: len() of unsized object\r\nUncaught exception. Entering post mortem debugging\r\nRunning 'cont' or 'step' will restart the program\r\n\u003e /sfs/fs5/home-sh/sunip229/opt/miniconda3/envs/py37_forge_jore/lib/python3.7/site-packages/matplotlib/ticker.py(2189)tick_values()\r\n-\u003e have_subs = len(subs) \u003e 1 or (len(subs == 1) and subs[0] != 1.0)\r\n(Pdb) subs\r\narray(100.)\r\n(Pdb) subs.ndim\r\n0\r\n\r\n```\r\n\r\nMaybe `subs` should be converted to a one dimensional array first.\r\n\r\nThe versions of the related programs are:\r\n```\r\nmatplotlib                3.0.2            py37h8a2030e_1    conda-forge\r\nmatplotlib-base           3.0.2            py37h20b835b_1    conda-forge\r\ncairo                     1.14.12              h276e583_5    conda-forge\r\npycairo                   1.18.0           py37h4d1f301_0    conda-forge\r\npython                    3.7.1                h5001a0f_0    conda-forge\r\n```\r\n\r\nThe bug occurred at several plots. However, the creation of the plots is rather complex. Thus I have no minimal example that reproduces the bug for now. If this is necessary, however, I can try to construct one.\r\n","author":{"url":"https://github.com/jor-","@type":"Person","name":"jor-"},"datePublished":"2018-11-14T10:15:15.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":5},"url":"https://github.com/12806/matplotlib/issues/12806"}