René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: figures with SpanSelector(..., useblit=True) can't be saved to SVG or PDF","articleBody":"### Bug summary\n\na SpanSelector created with `useblit=True` causes an error when trying to save the figure as SVG. Reproducer is below, though I haven't tested all backends (only Agg and qtagg; both fail) or all output formats (only SVG, PDF, and PNG; PNG works and the other two don't). `useblit=False` allows SVG and PDF saving to work.\n\nfirst reported at https://github.com/mne-tools/mne-python/issues/13242 by @AasmaGupta, who did much of the initial isolation work. Tested on MPL 3.10.1 on Linux.\n\n### Code for reproduction\n\n```Python\nimport numpy as np\nimport matplotlib\n\nmatplotlib.use(\"Agg\")\nimport matplotlib.pyplot as plt\nfrom matplotlib.widgets import SpanSelector\n\n\ndef onselect(xmin, xmax, **kwargs):\n    pass\n\n\nfig, ax = plt.subplots()\nax.plot(np.random.randn(100, 3))\nspan_selector = SpanSelector(\n    ax,\n    onselect,\n    \"horizontal\",\n    useblit=True,\n)\n\nfig.savefig(\"test.svg\")  # 'FigureCanvasSVG' object has no attribute 'copy_from_bbox'\n```\n\n### Actual outcome\n\n```\n---------------------------------------------------------------------------\nAttributeError                            Traceback (most recent call last)\nFile ~/Desktop/svgmwe.py:22\n     14 ax.plot(np.random.randn(100, 3))\n     15 span_selector = SpanSelector(\n     16     ax,\n     17     onselect,\n     18     \"horizontal\",\n     19     useblit=True,\n     20 )\n---\u003e 22 fig.savefig(\"test.svg\")  # 'FigureCanvasSVG' object has no attribute 'copy_from_bbox'\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/figure.py:3490, in Figure.savefig(self, fname, transparent, **kwargs)\n   3488     for ax in self.axes:\n   3489         _recursively_make_axes_transparent(stack, ax)\n-\u003e 3490 self.canvas.print_figure(fname, **kwargs)\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/backend_bases.py:2184, in FigureCanvasBase.print_figure(self, filename, dpi, facecolor, edgecolor, orientation, format, bbox_inches, pad_inches, bbox_extra_artists, backend, **kwargs)\n   2180 try:\n   2181     # _get_renderer may change the figure dpi (as vector formats\n   2182     # force the figure dpi to 72), so we need to set it again here.\n   2183     with cbook._setattr_cm(self.figure, dpi=dpi):\n-\u003e 2184         result = print_method(\n   2185             filename,\n   2186             facecolor=facecolor,\n   2187             edgecolor=edgecolor,\n   2188             orientation=orientation,\n   2189             bbox_inches_restore=_bbox_inches_restore,\n   2190             **kwargs)\n   2191 finally:\n   2192     if bbox_inches and restore_bbox:\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/backend_bases.py:2040, in FigureCanvasBase._switch_canvas_and_return_print_method.\u003clocals\u003e.\u003clambda\u003e(*args, **kwargs)\n   2036     optional_kws = {  # Passed by print_figure for other renderers.\n   2037         \"dpi\", \"facecolor\", \"edgecolor\", \"orientation\",\n   2038         \"bbox_inches_restore\"}\n   2039     skip = optional_kws - {*inspect.signature(meth).parameters}\n-\u003e 2040     print_method = functools.wraps(meth)(lambda *args, **kwargs: meth(\n   2041         *args, **{k: v for k, v in kwargs.items() if k not in skip}))\n   2042 else:  # Let third-parties do as they see fit.\n   2043     print_method = meth\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/backends/backend_svg.py:1351, in FigureCanvasSVG.print_svg(self, filename, bbox_inches_restore, metadata)\n   1346 w, h = width * 72, height * 72\n   1347 renderer = MixedModeRenderer(\n   1348     self.figure, width, height, dpi,\n   1349     RendererSVG(w, h, fh, image_dpi=dpi, metadata=metadata),\n   1350     bbox_inches_restore=bbox_inches_restore)\n-\u003e 1351 self.figure.draw(renderer)\n   1352 renderer.finalize()\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/artist.py:94, in _finalize_rasterization.\u003clocals\u003e.draw_wrapper(artist, renderer, *args, **kwargs)\n     92 @wraps(draw)\n     93 def draw_wrapper(artist, renderer, *args, **kwargs):\n---\u003e 94     result = draw(artist, renderer, *args, **kwargs)\n     95     if renderer._rasterizing:\n     96         renderer.stop_rasterizing()\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/artist.py:71, in allow_rasterization.\u003clocals\u003e.draw_wrapper(artist, renderer)\n     68     if artist.get_agg_filter() is not None:\n     69         renderer.start_filter()\n---\u003e 71     return draw(artist, renderer)\n     72 finally:\n     73     if artist.get_agg_filter() is not None:\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/figure.py:3264, in Figure.draw(self, renderer)\n   3261 finally:\n   3262     self.stale = False\n-\u003e 3264 DrawEvent(\"draw_event\", self.canvas, renderer)._process()\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/backend_bases.py:1189, in Event._process(self)\n   1187 def _process(self):\n   1188     \"\"\"Process this event on ``self.canvas``, then unset ``guiEvent``.\"\"\"\n-\u003e 1189     self.canvas.callbacks.process(self.name, self)\n   1190     self.guiEvent = None\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/cbook.py:366, in CallbackRegistry.process(self, s, *args, **kwargs)\n    364 except Exception as exc:\n    365     if self.exception_handler is not None:\n--\u003e 366         self.exception_handler(exc)\n    367     else:\n    368         raise\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/cbook.py:110, in _exception_printer(exc)\n    108 def _exception_printer(exc):\n    109     if _get_running_interactive_framework() in [\"headless\", None]:\n--\u003e 110         raise exc\n    111     else:\n    112         traceback.print_exc()\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/cbook.py:361, in CallbackRegistry.process(self, s, *args, **kwargs)\n    359 if func is not None:\n    360     try:\n--\u003e 361         func(*args, **kwargs)\n    362     # this does not capture KeyboardInterrupt, SystemExit,\n    363     # and GeneratorExit\n    364     except Exception as exc:\n\nFile /opt/mambaforge/envs/mnedev/lib/python3.13/site-packages/matplotlib/widgets.py:2167, in _SelectorWidget.update_background(self, event)\n   2165             stack.enter_context(artist._cm_set(visible=False))\n   2166         self.canvas.draw()\n-\u003e 2167     self.background = self.canvas.copy_from_bbox(self.ax.bbox)\n   2168 if needs_redraw:\n   2169     for artist in artists:\n\nAttributeError: 'FigureCanvasSVG' object has no attribute 'copy_from_bbox'\n```\n\n### Expected outcome\n\nFigure is saved normally.\n\n### Additional information\n\n_No response_\n\n### Operating system\n\nLinux\n\n### Matplotlib Version\n\n3.10.1\n\n### Matplotlib Backend\n\nAgg and QtAgg\n\n### Python version\n\n3.13.2\n\n### Jupyter version\n\nn/a\n\n### Installation\n\nconda","author":{"url":"https://github.com/drammock","@type":"Person","name":"drammock"},"datePublished":"2025-08-29T15:09:31.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/30485/matplotlib/issues/30485"}