from pathlib import Path

import matplotlib
matplotlib.use("Agg")

import matplotlib.pyplot as plt

output = Path("headless-plot.png")
fig, ax = plt.subplots(layout="constrained")
ax.plot([1, 2, 3, 4], [2, 4, 3, 5], marker="o")
ax.set_title("Headless Matplotlib")
ax.set_xlabel("Run")
ax.set_ylabel("Value")
fig.savefig(output, dpi=150)
plt.close(fig)

print(f"backend: {matplotlib.get_backend()}")
print(f"saved: {output.name}")
print(f"bytes: {output.stat().st_size}")