Python matplotlib图中的复杂箭头形状

发布于03月26日

我试图在matplotlib中添加一个复杂的箭头形状来表示"跳转"."(见草图)

生成"井"的代码足够简单，这里供参考.

import matplotlib.pyplot as plt
import numpy as np

fig,ax = plt.subplots(dpi=100)
fig.patch.set_alpha(0.9)
L=2
def well(x,depth=10,centre=0,flatten=0.2):
    return -depth * np.exp(-0.5 * ((x-centre)/flatten)**2)

wells=[-2*L,-1*L,0,L,2*L]
wells_xs=[]
for centre in wells:
    wells_xs.append(np.linspace(centre-0.5*L,centre+0.5*L,100))

for center,space in zip(wells,wells_xs):
    d=8 if center==0 else 1
    flatten=0.3 if center==0 else 0.4
    ax.plot(space,well(space,d,center,flatten),'deepskyblue')
plt.show()

我试图表明一个 idea ，即某个东西从右边的"坑"跳到深井，越过"小山"."所以直接从A指向B的箭头看起来不对. [3][2][3][2][3][2][3][2][3] X轴)

TL;DR

您可以使用matplotlib.patches.FancyArrowPatch在图形上绘制箭头.

Answer

matplotlib.patches中的FancyArrowPatch类允许您使用ax.add_patch(arrow)创建一个自定义箭头以添加到图形中. Select 正确的选项来获得您想要的确切箭头形状可能有点麻烦，但这段代码应该提供一个很好的起点.您可以调整起点/终点、曲率，甚至连接样式本身，以更改箭头的路径.

import matplotlib.pyplot as plt
import numpy as np
from matplotlib.patches import FancyArrowPatch


def well(x, depth=10, centre=0, flatten=0.2):
    return -depth * np.exp(-0.5 * ((x-centre)/flatten)**2)


def get_arrow(start_point, end_point, line_width=2.0, color="red", curvature=1.0, mutation_scale=20):
    arrow_style = f'->'
    connection_style = f'arc3, rad={curvature}'
    arrow = FancyArrowPatch(start_point, end_point, connectionstyle=connection_style, arrowstyle=arrow_style, color=color, linewidth=line_width, mutation_scale=mutation_scale)
    return arrow


fig, ax = plt.subplots(dpi=100)
fig.patch.set_alpha(0.9)
L = 2

wells = [-2*L, -1*L, 0, L, 2*L]
wells_xs = []
for centre in wells:
    wells_xs.append(np.linspace(centre-0.5*L, centre+0.5*L, 100))

for center, space in zip(wells, wells_xs):
    d = 8 if center == 0 else 1
    flatten = 0.3 if center == 0 else 0.4
    ax.plot(space, well(space, d, center, flatten), 'deepskyblue')

start_point = (wells[3], 0)
end_point = (wells[2], -2)
arrow = get_arrow(start_point, end_point)

ax.add_patch(arrow)
plt.show()