get_path（）從matplotlib.patches返回一個Circle

Question

有沒有人知道從matplotlib.patches返回的Circle的get_path()是什麼？圓圈的get_path()正在返回與原始圓圈不同的東西，這可以從下面的代碼結果中看出。從附圖中可以看出，原始橙色圈與原始圈的get_path()的藍色圈完全不同。

import numpy as np 
import matplotlib 
from matplotlib.patches import Circle, Wedge, Polygon, Ellipse 
from matplotlib.collections import PatchCollection 
import matplotlib.pyplot as plt 
import matplotlib.patches as matpatches 


fig, ax = plt.subplots(figsize=(8, 8)) 
patches = [] 


circle = Circle((2, 2), 2) 
patches.append(circle) 

print patches[0].get_path() 
print patches[0].get_verts() 

polygon = matpatches.PathPatch(patches[0].get_path()) 
patches.append(polygon) 


colors = 2*np.random.rand(len(patches)) 
p = PatchCollection(patches, cmap=matplotlib.cm.jet, alpha=0.4) 
p.set_array(np.array(colors)) 
ax.add_collection(p) 

plt.axis([-10, 10, -10, 10]) 

plt.show() 

fig.savefig('test.png') 

contain2 = patches[0].get_path().contains_points([[0.5, 0.5], [1.0, 1.0]]) 
print contain2 
contain3 = patches[0].contains_point([0.5, 0.5]) 
print contain3 
contain4 = patches[0].contains_point([1.0, 1.0]) 
print contain4 

Answer 1

圓的路徑是單位圓，而且matplotlib顯示它作爲與指定經由2D仿射變換的中心和半徑的圓的方式。如果您想要轉換路徑，則需要獲取路徑和轉換，並將轉換應用於路徑。

# Create the initial circle 
circle = Circle([2,2], 2); 

# Get the path and the affine transformation 
path = circle.get_path() 
transform = circle.get_transform() 

# Now apply the transform to the path 
newpath = transform.transform_path(path) 

# Now you can use this 
polygon = matpatches.PathPatch(newpath) 
patches.append(polygon)