The contour label (clabel) manual mode fails place any labels. When I click the plot I get an error: 'QuadContourSet' object has no attribute 'ax' and no labels are added. I put the Contour Label Demo ...
I propose to remove the C++ quad contouring code that is in Matplotlib, which I originally wrote in 2014, and replace it with use of a new external dependency ContourPy. ContourPy is a new Python/C++ ...