René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Plot disappear when blit is on","articleBody":"Already posted on stackoverflow but here should be more appropriate.\r\n\r\n### Bug report\r\n\r\n**Bug summary**\r\n\r\nFirst, good morning.\r\nAs the title describes, my plot disappears when the blitting option is on. I explain a bit further : I am making animations to display the solution of some differential equations and the code will become more and more heavy. I need the blitting option to have smooth animations\r\n and not to \"render\" the widgets everytime but I also need a button to start/stop the animation. I am using FuncAnimation. The thing is when I stop the animation with the \"myAnimation.event_source.stop()\" command linked to a widget button, the plot disappears (in some cases the moment my mouse cursor gets out of the pause button, some cases as soon as I press the button). The ax stays empty as long as the animation is on pause and the plot comes back animated when I restart with \"myAnimation.event_source.start()\".\r\n![python_2020-06-19_10-04-11](https://user-images.githubusercontent.com/67142515/85111393-8e9d8780-b214-11ea-9586-f03f8a8d2c41.png)\r\n**Code for reproduction**\r\nA mock version of the code that is not the code I'm trying to write but simplifies the computations and makes it more readable.\r\n\r\n\r\n```python\r\nimport numpy as np\r\nimport matplotlib.pyplot as plt\r\nimport matplotlib.animation as animation\r\n\r\nclass plotanimation:\r\n    def __init__(self):\r\n        self.fig,self.ax=plt.subplots()\r\n        self.x=np.linspace(-10,10,1000)\r\n        self.N=200\r\n        self.interv=50\r\n        self.n0=1./(4*np.pi*2e-4*0.1)**0.5 * np.exp(-self.x**2/(4*2e-4*0.1))  \r\n        self.p,=self.ax.plot(self.x,self.n0)\r\n        self.anim_running = True\r\n        self.Myanimation=animation.FuncAnimation(self.fig, self.update,frames=self.N,interval=self.interv,blit=True)\r\n    def update(self,i):\r\n        self.n0+=i/100\r\n        self.p.set_ydata(self.n0)\r\n        return self.p,\r\n    def animate(self):\r\n        pause_ax = self.fig.add_axes((0.7, 0.025, 0.1, 0.04))\r\n        pause_button = Button(pause_ax, 'pause', hovercolor='0.975')\r\n        pause_button.on_clicked(self._pause)\r\n        plt.show()\r\n    def _pause(self, event):\r\n        if self.anim_running:\r\n            self.Myanimation.event_source.stop()\r\n            self.anim_running = False\r\n        else:\r\n            self.Myanimation.event_source.start()\r\n            self.anim_running = True\r\n    \r\n    \r\nanimated_plot = plotanimation()\r\nanimated_plot.animate()\r\n```\r\n\r\n\r\n```\r\n# If applicable, paste the console output here\r\n#\r\n#\r\n```\r\n\r\n**Expected outcome**\r\n\r\nThe paused plot on the fig. Not an empty ax.\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: W10\r\n  * Matplotlib version:  (3.1.2)\r\n  * Matplotlib backend : TkAgg\r\n  * Python version: v3.8.1:1b293b6\r\n  * Jupyter version (if applicable): None\r\n  * Other libraries: Numpy, scipy\r\n\r\n\u003c!--Please tell us how you installed matplotlib and python e.g., from source, pip, conda--\u003e\r\n\u003c!--If you installed from conda, please specify which channel you used if not the default--\u003e\r\n\r\nMatplotlib was installed with pip. Conda is not installed.\r\nThank you a lot.","author":{"url":"https://github.com/Luluser","@type":"Person","name":"Luluser"},"datePublished":"2020-06-19T08:09:10.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":4},"url":"https://github.com/17685/matplotlib/issues/17685"}