René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Issue with minor tick spacing in colorbar with custom Normalize class","articleBody":"### Bug report\r\n\r\n**Bug summary**\r\n\r\nMinor ticks don't appear in the right place in colorbars when a custom Normalize class is used.\r\n\r\n**Code for reproduction**\r\n\r\nThe following example requires [astropy](http://www.astropy.org). If needed I can try and provide an example that doesn't use this.\r\n\r\n```python\r\nimport numpy as np\r\nimport matplotlib.pyplot as plt\r\nfrom astropy.visualization import LogStretch, ImageNormalize, PercentileInterval\r\n\r\ndata = np.arange(256).reshape((16, 16))\r\n\r\nnorm = ImageNormalize(data, interval=PercentileInterval(99), stretch=LogStretch())\r\n\r\nplt.rcParams['xtick.minor.visible'] = True\r\n\r\nfig = plt.figure()\r\nax = fig.add_subplot(1, 1, 1)\r\nim = ax.imshow(data, norm=norm)\r\ncb = fig.colorbar(im)\r\nfig.savefig('test.png')\r\n```\r\n\r\n**Actual outcome**\r\n\r\n![test](https://user-images.githubusercontent.com/314716/48497051-4bef1e80-e82b-11e8-919d-a6bdcff03004.png)\r\n\r\n**Expected outcome**\r\n\r\nThe minor ticks should respect the spacing of the current stretch.\r\n\r\nI noticed that using LogNorm, the ticks used to be spaced incorrectly in Matplotlib 2.2 but this was fixed in Matplotlib 3.0. However, the minor ticks are still broken for custom normalizations as shown above.\r\n\r\n**Matplotlib version**\r\n\r\n  * Operating system: MacOS X 10.13.6\r\n  * Matplotlib version: 3.0.1\r\n  * Matplotlib backend: Agg\r\n  * Python version: 3.7.1\r\n","author":{"url":"https://github.com/astrofrog","@type":"Person","name":"astrofrog"},"datePublished":"2018-11-14T16:37:19.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/12808/matplotlib/issues/12808"}