title: python matplotlib: Plotting to GUI in non-main thread
body: <p>I had some issues with matplotlib runing in a non-main thread..</p>
  <p>I'm doing a GUI with tkinter that runs some operations in a new thread, showing a progress bar, etc.. then plot graphics.</p>
  <p>The problem is: the plot part just doesnt work and I that warning comes:</p>
  <p><em>UserWarning: Starting a Matplotlib GUI outside of the main thread will likely fail.</em></p>
  <p>There's a solution?</p>
  <p>Maybe if I can't call main thread back, can I run the matplotlib part in the main thread calling it's function in this non-main thread part of the code?</p>