René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"[Bug]: Contour plot is not updating after customization made to the color bar in the generated plot.","articleBody":"### Bug summary\n\nA contour plot is plotted with the minimum and maximum values of the parameter as color bar limits. Then when I try to make changes (such as limits and colormap) to the color bar from the toolbar of the generated plot it is not updating accordingly.  \r\n![1 Generated_plot](https://user-images.githubusercontent.com/40228243/169468987-f714688e-70c4-44a4-9280-251e4ba92f98.PNG)\r\n1. A sample plot. \r\n![2 Customizing_Colorbar](https://user-images.githubusercontent.com/40228243/169468991-ec1adc97-0a82-4f78-990e-3c7c847feeb8.PNG)\r\n2. Customizing the color bar. \r\n![3 Colorbar_options](https://user-images.githubusercontent.com/40228243/169468993-cf83c5fa-8fc1-40f9-9b6f-77085ce3cad5.PNG)\r\n3. Options for changing the color bar. \r\n![4 Colorbar_Changes_Not_reflected](https://user-images.githubusercontent.com/40228243/169468998-8cf9ca16-a1f0-48eb-b399-9c2ef80252f1.PNG)\r\n4. The changes are reflected in the color bar, but not in the plot. \r\nKindly suggest how I can update the plot according to the changes made in the color bar options.\n\n### Code for reproduction\n\n```python\n# A sample code.\r\nimport numpy as np\r\nimport matplotlib.pyplot as plt\r\n\r\norigin = 'lower'\r\n\r\ndelta = 0.025\r\n\r\nx = y = np.arange(-3.0, 3.01, delta)\r\nX, Y = np.meshgrid(x, y)\r\nZ1 = np.exp(-X**2 - Y**2)\r\nZ2 = np.exp(-(X - 1)**2 - (Y - 1)**2)\r\nZ = (Z1 - Z2) * 2\r\n\r\nnr, nc = Z.shape\r\n\r\n# put NaNs in one corner:\r\nZ[-nr // 6:, -nc // 6:] = np.nan\r\n# contourf will convert these to masked\r\n\r\n\r\nZ = np.ma.array(Z)\r\n# mask another corner:\r\nZ[:nr // 6, :nc // 6] = np.ma.masked\r\n\r\n# mask a circle in the middle:\r\ninterior = np.sqrt(X**2 + Y**2) \u003c 0.5\r\nZ[interior] = np.ma.masked\r\n\r\nfig1, ax2 = plt.subplots(constrained_layout=True)\r\nCS = ax2.contourf(X, Y, Z, 10, cmap=plt.cm.bone, origin=origin)\r\n\r\n# Note that in the following, we explicitly pass in a subset of the contour\r\n# levels used for the filled contours.  Alternatively, we could pass in\r\n# additional levels to provide extra resolution, or leave out the *levels*\r\n# keyword argument to use all of the original levels.\r\n\r\nCS2 = ax2.contour(CS, levels=CS.levels[::2], colors='r', origin=origin)\r\n\r\nax2.set_title('Nonsense (3 masked regions)')\r\nax2.set_xlabel('word length anomaly')\r\nax2.set_ylabel('sentence length anomaly')\r\n\r\n# Make a colorbar for the ContourSet returned by the contourf call.\r\ncbar = fig1.colorbar(CS)\r\ncbar.ax.set_ylabel('verbosity coefficient')\r\n# Add the contour line levels to the colorbar\r\ncbar.add_lines(CS2)\r\nplt.show()\n```\n\n\n### Actual outcome\n\n![1 Generated_plot](https://user-images.githubusercontent.com/40228243/169469852-69156ff9-fa76-41e5-b270-680cc3d65d93.PNG)\r\n\n\n### Expected outcome\n\n![5  Required_Plot](https://user-images.githubusercontent.com/40228243/169470613-e9846173-2928-4cd1-8d18-8de77d3671fe.png)\r\n\r\nThe following changes have been made to the code in order to get the expected plot.\r\n`lev = np.linspace(-0.5, 0.5, 10)`\r\n`CS = ax2.contourf(X, Y, Z, 10, cmap=plt.cm.rainbow, origin=origin, levels=lev)`\n\n### Additional information\n\n_No response_\n\n### Operating system\n\nWindows\n\n### Matplotlib Version\n\n3.4.3\n\n### Matplotlib Backend\n\nQt5Agg\n\n### Python version\n\nPython 3.8.12\n\n### Jupyter version\n\n_No response_\n\n### Installation\n\npip","author":{"url":"https://github.com/JishnuJeevan","@type":"Person","name":"JishnuJeevan"},"datePublished":"2022-05-20T06:57:54.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/23080/matplotlib/issues/23080"}