PR summary

This speeds up Path.get_extents which calls these bezier operations by a factor of 4-5x.

There are two changes here:

• We can hardcode the coefficient matrices for degrees up to 4, which is all we use anyway
• Instead of np.roots which does expensive eigenvalue decomposition, we can take advantage of the fact that we are only looking for roots on the [0, 1] interval and just do bisection for degree >= 3. Or we can calculate exactly for degree == 2. These both end up being much faster.

PR checklist

• [n/a] "closes #0000" is in the body of the PR description to link the related issue
• new and changed code is tested
• [n/a] Plotting related features are demonstrated in an example
• [n/a] New Features and API Changes are noted with a directive and release note
• [n/a] Documentation complies with general and docstring guidelines