René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: regression with LineCollection + TwoSlopeNorm colorbar in matplotlib 3.5.0b1","articleBody":"### Bug summary\n\nSome image comparison tests in a project of mine are failing when running matplotlib 3.50b1\r\n\n\n### Code for reproduction\n\n```python\nimport matplotlib.pyplot as plt\r\nfrom matplotlib.collections import LineCollection\r\nfrom matplotlib.colors import TwoSlopeNorm\r\nimport numpy as np\r\n\r\nx = np.linspace(0, 10, 100)\r\ny = np.sin(x)\r\n# generate some data within some interval that doesn't have 0 its central value\r\nz = y + 0.5\r\n\r\npoints = np.array([x, y]).T.reshape(-1, 1, 2)\r\nsegments = np.concatenate([points[:-1], points[1:]], axis=1)\r\n\r\n# adapted from\r\n# https://matplotlib.org/stable/gallery/lines_bars_and_markers/multicolored_line.html\r\nlc = LineCollection(segments, norm=TwoSlopeNorm(0), cmap=\"RdYlBu\")\r\nlc.set_array(z)\r\n\r\nfig, ax = plt.subplots()\r\n\r\n# this line is just to compensate for the fact that the limits are not\r\n# automatically handled when the plot just contains a single LineCollection artist\r\nax.set(xlim=(0, 10), ylim=(-1, 1))\r\n\r\nline = ax.add_collection(lc)\r\nfig.colorbar(line)\n```\n\n\n### Actual outcome\n\n![linecollection_mpl_v3 5 0b1](https://user-images.githubusercontent.com/14075922/132093627-e0e2ae13-77eb-4668-8894-42b9a15991ab.png)\r\n\n\n### Expected outcome\n\nThis is the results with matplotlib 3.4.3\r\n![linecollection_mpl_v3 4 3](https://user-images.githubusercontent.com/14075922/132093617-9b889a1a-6e9c-4ea9-a50c-a1957a1ea004.png)\r\n\n\n### Operating system\n\nOS/X\n\n### Matplotlib Version\n\n3.5.0b1\n\n### Matplotlib Backend\n\nMacOSX\n\n### Python version\n\n3.9.6\n\n### Jupyter version\n\nN/A\n\n### Other libraries\n\n_No response_\n\n### Installation\n\npip\n\n### Conda channel\n\n_No response_","author":{"url":"https://github.com/neutrinoceros","@type":"Person","name":"neutrinoceros"},"datePublished":"2021-09-04T11:58:55.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":18},"url":"https://github.com/20993/matplotlib/issues/20993"}