René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Modifying Axes' position also alters the original Bbox object used for initialization","articleBody":"### Bug summary\n\nWhen an Axes is initialized using a Bbox object, changing the Axes' position (for example, via `ax.set_position`) will also alter the original Bbox object. This is because the Axes retains a reference to the Bbox object rather than creating a separate copy during initialization.\n\n### Code for reproduction\n\n```Python\nimport matplotlib.pyplot as plt\r\nfrom matplotlib.transforms import Bbox\r\n\r\nbbox = Bbox([[0.1, 0.1], [0.9, 0.9]])\r\nfig = plt.figure()\r\nax = fig.add_axes(bbox)\r\nax.set_position([0.25, 0.25, 0.5, 0.5])\r\nprint(bbox)\r\nprint(id(bbox), id(ax._position))\n```\n\n\n### Actual outcome\n\nBbox(x0=0.25, y0=0.25, x1=0.75, y1=0.75)\r\n140507022809120 140507022809120\n\n### Expected outcome\n\nBbox(x0=0.1, y0=0.1, x1=0.9, y1=0.9)\r\n... ...  # Two different IDs\n\n### Additional information\n\nThis issue originates from `_AxesBase.__init__`,\r\n\r\nhttps://github.com/matplotlib/matplotlib/blob/8d64f03a1f501ba0019279bf2f8db3930d1fe33f/lib/matplotlib/axes/_base.py#L650-L651\r\n\r\nwhere `args[0]` is directly assigned to `self._position` without making a copy.\r\n\r\nI don't know if this is a bug or a feature, but it does break encapsulation.\r\n\r\nAdditionally, some other initialization methods (for example, `Bbox.__init__`) that use `np.asarray` instead of `np.array` can cause similar issues.\n\n### Operating system\n\n_No response_\n\n### Matplotlib Version\n\n3.10.0\n\n### Matplotlib Backend\n\n_No response_\n\n### Python version\n\n_No response_\n\n### Jupyter version\n\n_No response_\n\n### Installation\n\nNone","author":{"url":"https://github.com/hu-xiaonan","@type":"Person","name":"hu-xiaonan"},"datePublished":"2025-01-06T08:07:47.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/29410/matplotlib/issues/29410"}