如何更改Python matplotlib面片多边形中边缘线的不透明度/透明度（alpha）？

Question

我想更改这些多边形的边线的alpha，而不受matplotlib面片多边形的影响。我希望边线的alpha大于多边形的面片。面片超出了边线，如何在边线上完美地拟合面片，这样它就不会超出多边形

代码如下：

import matplotlib.pyplot as plt
import numpy as np
from matplotlib.patches import Polygon
from scipy.spatial import ConvexHull
hull = ConvexHull(points)
# plt.plot(points[:,0], points[:,1], 'o')
cent = np.mean(points, 0)
pts = []
for pt in points[hull.simplices]:
        pts.append(pt[0].tolist())
        pts.append(pt[1].tolist())


pts.sort(key=lambda p: np.arctan2(p[1] - cent[1],
                        p[0] - cent[0]))
pts = pts[0::2]  # Deleting duplicates
pts.insert(len(pts), pts[0])
k = 0.4
poly = Polygon(k*(np.array(pts)- cent) + cent,fill=True,closed=True,
        facecolor=color, alpha=0.2,edgecolor=color,linewidth=7)
plt.gca().add_patch(poly)
plt.show()

输出如下：

Answer 1

我认为您可能需要分别绘制它们-基本上：

poly = Polygon(k*(np.array(pts)- cent) + cent,fill=True,closed=True,
        facecolor=color, alpha=0.2)
polyEdge = Polygon(k*(np.array(pts)- cent) + cent,fill=False,closed=True,
        alpha=0.8,edgecolor=color,linewidth=7)

给人这样的印象：

import matplotlib.pyplot as plt
import numpy as np
from matplotlib.patches import Polygon
from scipy.spatial import ConvexHull
points = np.array([(.30,.60), (.50,.40), (0,.30),(.15,.25),(.20,0),(.50,.10),(.55,.20),(.70,.30)])
hull = ConvexHull(points)
# plt.plot(points[:,0], points[:,1], 'o')
cent = np.mean(points, 0)
pts = []
for pt in points[hull.simplices]:
        pts.append(pt[0].tolist())
        pts.append(pt[1].tolist())

color='red'
pts.sort(key=lambda p: np.arctan2(p[1] - cent[1],
                        p[0] - cent[0]))
pts = pts[0::2]  # Deleting duplicates
pts.insert(len(pts), pts[0])
k = 0.4
poly = Polygon(k*(np.array(pts)- cent) + cent,fill=True,closed=True,
        facecolor=color, alpha=0.2)
polyEdge = Polygon(k*(np.array(pts)- cent) + cent,fill=False,closed=True,
        alpha=0.8,edgecolor=color,linewidth=7)

plt.gca().add_patch(poly)
plt.gca().add_patch(polyEdge)
plt.show()