René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Large pixels may overlap when using imshow()","articleBody":"### Bug summary\n\nWhen using `imshow()` with a small array (large pixels), the pixel patches can end up slightly misaligned. This becomes especially obvious when thin grid lines are overlaid on the figure.\n\n### Code for reproduction\n\n```Python\nimport matplotlib.pyplot as plt\nimport numpy as np\n\nfig,ax = plt.subplots() \nN = 12 \nax.imshow(np.random.rand(N, N)) \nseps = np.arange(-0.5, N) \nax.vlines(seps, -0.5, N - 0.5, linewidth=1)\nax.hlines(seps, -0.5, N - 0.5, linewidth=1)\nplt.show()\n```\n\n### Actual outcome\n\n\u003cimg width=\"639\" height=\"560\" alt=\"Image\" src=\"https://github.com/user-attachments/assets/a387d152-53c6-4d9b-a75d-fd19f2f54bcd\" /\u003e\n\n### Expected outcome\n\nA figure where none of the pixel patches overlap their respective grid lines.\n\n### Additional information\n\nI originally thought this was the same issue as #14143, see [my original comment](https://github.com/matplotlib/matplotlib/issues/14143#issuecomment-584833923). Eventually that bug was fixed but this issue remained. [To quote @ayshih](https://github.com/matplotlib/matplotlib/issues/14143#issuecomment-3781269196):\n\n\u003e Based on my investigation so far, the problem in your example is indeed distinct from the original issue, and it is very important to fix. It's not a bug internal to the image-resampling code, but rather it has to do with how image placement affects what resampling is requested and how the resampled image is drawn.\n\n### Operating system\n\nDebian\n\n### Matplotlib Version\n\n3.11.0.dev1652+gddd4196c7 (but first found around 3.3.0)\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\nuv","author":{"url":"https://github.com/adeak","@type":"Person","name":"adeak"},"datePublished":"2026-01-21T21:55:53.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/31009/matplotlib/issues/31009"}