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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: integer colours for pcolorfast / quadmesh","articleBody":"### Bug summary\r\n\r\nI get an error \r\n```\r\nValueError: RGBA values should be within 0-1 range\r\n```\r\nwhen passing a byte/integer array to pcolorfast to code the colors as RGBA.  It also fails when data type is `uint8` \r\n\r\n### Code for reproduction\r\n\r\n```python\r\nimport numpy as np\r\nimport matplotlib.pyplot as plt\r\nfrom matplotlib.cm import get_cmap\r\ncmap = get_cmap('bwr_r'')\r\nfig, ax = plt.subplots()\r\nx, y = np.mgrid[0:10:100j, 0:10:100j]\r\nv = np.abs(np.sin(x) * np.cos(y))\r\nc = (cmap(v[:-1, :-1]) * 255).astype(np.int64)\r\nax.pcolorfast(x, y, c)\r\n```\r\n\r\n\r\n### Actual outcome\r\n\r\n```\r\nValueError: RGBA values should be within 0-1 range\r\n```\r\n\r\n### Expected outcome\r\n\r\na plot in in some bluish colour\r\n\r\n### Additional information\r\n\r\nfixes:\r\n\r\n1) in `colors.py`, line 321:\r\n```\r\nif (isinstance(c, np.ndarray) and c.dtype.kind in \"if\"\r\n```\r\nshould be replaced by\r\n```\r\nif (isinstance(c, np.ndarray) and c.dtype.kind in \"ifu\"\r\n```\r\nto allow for unsigned int values as well\r\n\r\n2) in line 343:\r\n```\r\n        if np.any((result \u003c 0) | (result \u003e 1)):\r\n            raise ValueError(\"RGBA values should be within 0-1 range\")\r\n```\r\nshould be replaced by a test including dtype.kind - for 'i' and 'u'. \r\nIt may be sufficient to comment it out as a quick fix as it is definitively more broken having it in.\r\n\r\n ```\r\n        if c.dtype.kind in \"f\" and np.any((result \u003c 0) | (result \u003e 1)):\r\n            raise ValueError(\"RGBA float values should be within 0-1 range\")\r\n        if c.dtype.kind in \"ui\" and np.any((result \u003c 0) | (result \u003e 255)):\r\n            raise ValueError(\"RGBA fixed values should be within 0-255 range\")\r\n```\r\neven with this it does not quite work\r\n\r\n### Operating system\r\n\r\n 5.15.13-200.fc35.x86_64\r\n\r\n### Matplotlib Version\r\n\r\n3.5.1\r\n\r\n### Matplotlib Backend\r\n\r\ngtk3\r\n\r\n### Python version\r\n\r\n3.10.1\r\n\r\n### Jupyter version\r\n\r\n8.0.0\r\n\r\n### Installation\r\n\r\npip","author":{"url":"https://github.com/2sn","@type":"Person","name":"2sn"},"datePublished":"2022-01-15T06:20:29.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":10},"url":"https://github.com/22236/matplotlib/issues/22236"}