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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Image color limits not correctly updated with set_clim() IFF color bar present AND new norm.vmin \u003e old norm.vmax","articleBody":"### Bug summary\n\nI experienced some specific odd cases where I noticed that the colors of an image were not correctly set after updating the image data and setting new color limits with set_clim(). After debugging I was able to reproduce with a minimal example,..\n\n\n### Code for reproduction\n\n```Python\nimport numpy as np\nfrom matplotlib import pyplot as plt\n\n\n# Create test data\nnp.random.seed(19771105)\ndata_0 = np.round(np.random.rand(10, 20), 1)\ndata_1 = data_0 + 10\n\n# Compute data range\nrange_0 = data_0.min(), data_0.max()\nrange_1 = data_1.min(), data_1.max()\n\n# Plot data as image; Auto adjusts colorbar scale to value range\nimage = plt.imshow(data_0)\ncbar = plt.colorbar(image)  # NOTE: Problem does not occur if colorbar not created!\n\nprint(f'expected norm = {range_0}')\nprint(f'actual   norm = {image.norm.vmin, image.norm.vmax}')\n\n# Change image data and update image color limits\nimage.set_data(data_1)\nimage.set_clim(range_1)\n\nprint(f'expected norm = {range_1}')\nprint(f'actual   norm = {image.norm.vmin, image.norm.vmax}')  # Incorrect!\n\nplt.show()\n```\n\n### Actual outcome\n\n```\nexpected initial norm = (0.0, 1.0)\ncomputed initial norm = (0.0, 1.0)\nexpected updated norm = (10.0, 11.0)\ncomputed updated norm = (0.9, 11.0)\n```\n\n![Image](https://github.com/user-attachments/assets/48488083-ce5c-4068-a747-fadc4c6e1422)\n\n### Expected outcome\n\n```\nexpected initial norm = (0.0, 1.0)\ncomputed initial norm = (0.0, 1.0)\nexpected updated norm = (10.0, 11.0)\ncomputed updated norm = (10.0, 11.0)\n```\n\n![Image](https://github.com/user-attachments/assets/727b9406-c0f1-4fb5-9aec-2f18677a4c05)\n\n### Additional information\n\nOnly happens if color bar is present; Removing the line that creates it from code lets you see the correct image (minus color bar).\nData dependent; Only occurs if the lowest value of the new image data is higher than the highest value of the old image data (Hence +10 in the code example).\n\n\n### Operating system\n\nWindows 10\n\n### Matplotlib Version\n\n\u003e3.6.0\n\n### Matplotlib Backend\n\nQtAgg\n\n### Python version\n\n3.11.9\n\n### Jupyter version\n\n-\n\n### Installation\n\npip","author":{"url":"https://github.com/erikdendekker","@type":"Person","name":"erikdendekker"},"datePublished":"2025-01-25T21:46:43.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":15},"url":"https://github.com/29522/matplotlib/issues/29522"}