在某种程度上,是的,事情就是这样。
重点是边缘实际上是在圆的边缘上绘制的。
这意味着边缘宽度的一半绘制在圆表面的顶部,另一半绘制在外部。如果现在你设置alpha<1.0
正如您正确得出的结论,您会看到面部颜色和边缘颜色的重叠。
然而,你可以摆脱那个“额外的边界”。以下是两种方法,哪一种最适合您取决于您到底想做什么。
第一个建议:
恕我直言,最简单的是只为facecolor
。这可以通过设置 alpha 通道来完成facecolor
直接并省略alpha
呼吁中的论点Circle
。您可以使用以下命令设置 alpha 通道colorConverter
:
from matplotlib.colors import colorConverter
import matplotlib.pyplot as plt
fig, ax = plt.subplots(figsize=(8, 8))
ax.axis('equal')
ax.set_xlim(0,1)
ax.set_ylim(0,1)
# Here you set alpha for the faceolor
fc = colorConverter.to_rgba('green', alpha=0.5)
point = (1.0, 1.0)
r = 1.0
lw = 15.0
ec = 'orange'
# NOTE: do not set alpha when calling Circle!
c = plt.Circle(point, r,fc=fc, ec=ec, lw=lw)
ax.add_artist(c)
plt.show()
第二个建议
更详细的选项是在仅绘制面后用白色边缘“擦拭”圆的边缘,然后仅绘制边缘。
通过这种方法,两种颜色都随 Alpha 通道一起出现。但请注意,在这种情况下,位于边缘“下方”的任何对象都将被边缘完全遮盖:
import matplotlib.pyplot as plt
from matplotlib.collections import PatchCollection
point = (1.0, 1.0)
r = 1.0
alpha = 0.5
lw = 15.0
fc = 'green'
ec = 'orange'
# First only draw the facecolor
c_face = plt.Circle(point, r, alpha=alpha, fc=fc, lw=0.0)
# Draw a non-transparent white edge to wipe the facecolor where they overlap
c_wipe = plt.Circle(point, r, alpha=1.0, ec='white', fc='none', lw=lw)
# Now draw only the edge
c_edge = plt.Circle(point, r, alpha=alpha, fc='none', ec=ec, lw=lw)
circle_patch = PatchCollection([c_face, c_wipe, c_edge], match_original=True)
fig, ax = plt.subplots(figsize=(8, 8))
ax.axis('equal')
ax.set_xlim(0,1)
ax.set_ylim(0,1)
ax.add_artist(circle_patch)
plt.show()
这是一个要点 https://gist.github.com/j-i-l/a88720d934b921a9338030a55dced2d1根据第二个建议处理这个问题。只需下载mod_patch.py https://gist.github.com/j-i-l/a88720d934b921a9338030a55dced2d1#file-mod_patch-py文件然后就可以走了。
以下是它的使用方法:
import matplotlib.pyplot as plt
from mod_patch import get_Patch
fig, ax = plt.subplots(figsize=(8,8))
c = get_Patch(plt.Circle, (0,0.5), 0.5, facecolor='green', edgecolor='orange', alpha=0.5, lw=15)
ax.add_artist(c)
r = get_Patch(plt.Rectangle, (0.5,0), 0.5, 0.5, facecolor='green', edgecolor='orange', alpha=0.5, lw=15)
ax.add_artist(r)
plt.show()
为了完整起见,这里定义get_Patch
:
from matplotlib.collections import PatchCollection
def get_Patch(a_Patch, *args, **kwargs):
background_color = kwargs.pop(
'bgc',
kwargs.pop('background_color', 'white')
)
alpha = kwargs.get('alpha', 1.0)
patches = []
lw = kwargs.get('lw', kwargs.get('linewidth', 0.0))
if alpha < 1.0 and lw:
color = kwargs.get('c', kwargs.get('color', None))
fc = kwargs.get('facecolor', kwargs.get('fc', None))
ec = kwargs.get('edgecolor', kwargs.get('ec', None))
face_kwargs = dict(kwargs)
face_kwargs['fc'] = fc if fc is not None else color
face_kwargs['lw'] = 0.0
p_face = a_Patch(*args, **face_kwargs)
patches.append(p_face)
wipe_kwargs = dict(kwargs)
wipe_kwargs['fc'] = 'none'
wipe_kwargs['ec'] = background_color
wipe_kwargs['alpha'] = 1.0
p_wipe = a_Patch(*args, **wipe_kwargs)
patches.append(p_wipe)
edge_kwargs = dict(kwargs)
edge_kwargs['fc'] = 'none'
edge_kwargs['ec'] = ec if ec is not None else color
p_edge = a_Patch(*args, **edge_kwargs)
patches.append(p_edge)
else:
p_simple = a_Patch(*args, **kwargs)
patches.append(p_simple)
return PatchCollection(patches, match_original=True)