René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Colorbar update error with clim change in multi_image.py example","articleBody":"\u003c!--To help us understand and resolve your issue, please fill out the form to the best of your ability.--\u003e\r\n\u003c!--You can feel free to delete the sections that do not apply.--\u003e\r\n\r\n### Bug report\r\n\r\n**Bug summary**\r\n\r\nIn the multi_image example, the colorbar is responding correctly to `set_clim` only when called on the image to which the colorbar is directly attached.   \r\n\r\n**Code for reproduction**\r\nThis is just the example, https://matplotlib.org/gallery/images_contours_and_fields/multi_image.html, with manipulation of the clim at the bottom.\r\n```python\r\nfrom matplotlib import colors\r\nimport matplotlib.pyplot as plt\r\nimport numpy as np\r\n\r\nnp.random.seed(19680801)\r\nNr = 3\r\nNc = 2\r\ncmap = \"cool\"\r\n\r\nfig, axs = plt.subplots(Nr, Nc)\r\nfig.suptitle('Multiple images')\r\n\r\nimages = []\r\nfor i in range(Nr):\r\n    for j in range(Nc):\r\n        # Generate data with a range that varies from one plot to the next.\r\n        data = ((1 + i + j) / 10) * np.random.rand(10, 20) * 1e-6\r\n        images.append(axs[i, j].imshow(data, cmap=cmap))\r\n        axs[i, j].label_outer()\r\n\r\n# Find the min and max of all colors for use in setting the color scale.\r\nvmin = min(image.get_array().min() for image in images)\r\nvmax = max(image.get_array().max() for image in images)\r\nnorm = colors.Normalize(vmin=vmin, vmax=vmax)\r\nfor im in images:\r\n    im.set_norm(norm)\r\n\r\nfig.colorbar(images[0], ax=axs, orientation='horizontal', fraction=.1)\r\n\r\n\r\n# Make images respond to changes in the norm of other images (e.g. via the\r\n# \"edit axis, curves and images parameters\" GUI on Qt), but be careful not to\r\n# recurse infinitely!\r\ndef update(changed_image):\r\n    for im in images:\r\n        if (changed_image.get_cmap() != im.get_cmap()\r\n                or changed_image.get_clim() != im.get_clim()):\r\n            im.set_cmap(changed_image.get_cmap())\r\n            im.set_clim(changed_image.get_clim())\r\n\r\n\r\nfor im in images:\r\n    im.callbacksSM.connect('changed', update)\r\n\r\nimages[1].set_clim(1e-9, 2e-8)\r\nfig.savefig('ax1_bad.png')\r\nimages[0].set_clim(1e-9, 2e-8)\r\nfig.savefig('ax0_good.png')\r\n\r\n```\r\n\r\n**Actual outcome**\r\nax1_bad.png:\r\n\r\n![ax1_bad](https://user-images.githubusercontent.com/85125/78626771-716b3680-782b-11ea-844b-c12c7eeb396d.png)\r\n\r\n\r\n**Expected outcome**\r\nax0_good.png:\r\n\r\n![ax0_good](https://user-images.githubusercontent.com/85125/78626732-4f71b400-782b-11ea-8ed4-948dbeb49d20.png)\r\n\r\n\r\n**Matplotlib version**\r\n\u003c!--Please specify your platform and versions of the relevant libraries you are using:--\u003e\r\n  * Operating system: OSX\r\n  * Matplotlib version:  3.1.2\r\n  * Matplotlib backend (`print(matplotlib.get_backend())`): MacOSX, agg\r\n  * Python version: 3.7\r\n ","author":{"url":"https://github.com/efiring","@type":"Person","name":"efiring"},"datePublished":"2020-04-07T03:30:23.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/17052/matplotlib/issues/17052"}