PR summary

I've been having a lot of fun profiling the past two days. This PR is the result of optimizing slow bits of the text rendering code paths that are called downstream of axis3d._draw_ticks(). None of these changes are 3D specific, so they should speed up 2D draw times as well. The non-agg-rendering code in this part of the stack is sped up by a cumulative 2.2x, which is an 8% reduction in the total draw time for my test script of an empty 3D plot.

The commits are all self-contained, so I can break them apart if that's easier to review.

Summary of the changes:

text.py:

• Rework the font property cache to use a plain dict instead of lru_cache, and use a tuple-based cache key. This avoids expensive copying of the whole FontProperties object on every cache lookup.
• Add @lru_cache for rotation transforms via a _rotate(theta) helper function (common case is only a few angles)
• Add fast path to skip rotation transform operations when rotation=0 (the most common case)
• Use direct indexing instead of numpy array operations for several small lists

font_manager.py:

• Implement __copy__ method on FontProperties that bypasses __init__ validation

lines.py

• Add fast path for same-shape x/y arrays using direct assignment instead of broadcast_arrays
• Replace .T unpacking with column slicing for views

path.py

• Inline shape validation instead of calling _api.check_shape

transforms.py

• Prefer direct array construction in Bbox.from_extents over np.reshape

Before:

After (less time on things that aren't draw_text):

Test script:

import time
import matplotlib.pyplot as plt

print("Starting...")

fig = plt.figure()
ax = fig.add_subplot(111, projection='3d')

print("Timing...")

start_time = time.perf_counter()
for i in range(250):
    ax.view_init(elev=i, azim=i)
    fig.canvas.draw()
end_time = time.perf_counter()

plt.close()

print(f"Time taken: {end_time - start_time:.4f} seconds")

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