path_patch.py

# -*- coding: utf-8 -*-
# https://matplotlib.org/3.2.1/gallery/shapes_and_collections/path_patch.html

import sys

import matplotlib.patches as mpatches
import matplotlib.path as mpath
from matplotlib.backends.backend_qt5agg import FigureCanvas
from matplotlib.figure import Figure
from PyQt5.QtWidgets import QApplication

app = QApplication(sys.argv)

fig = Figure(figsize=(8, 6))
canvas = FigureCanvas(fig)
canvas.resize(640, 480)
canvas.show()

ax = fig.subplots()

Path = mpath.Path
path_data = [
    (Path.MOVETO, (1.58, -2.57)),
    (Path.CURVE4, (0.35, -1.1)),
    (Path.CURVE4, (-1.75, 2.0)),
    (Path.CURVE4, (0.375, 2.0)),
    (Path.LINETO, (0.85, 1.15)),
    (Path.CURVE4, (2.2, 3.2)),
    (Path.CURVE4, (3, 0.05)),
    (Path.CURVE4, (2.0, -0.5)),
    (Path.CLOSEPOLY, (1.58, -2.57)),
]
codes, verts = zip(*path_data)
path = mpath.Path(verts, codes)
patch = mpatches.PathPatch(path, facecolor="r", alpha=0.5)
ax.add_patch(patch)

# plot control points and connecting lines
x, y = zip(*path.vertices)
(line,) = ax.plot(x, y, "go-")

ax.grid()
ax.axis("equal")

sys.exit(app.exec_())