python - 创建自定义标记作为复杂顶点的并集

Question

我一直在寻找一个优雅/简单(工作!)的解决方案来为 matplotlib 创建新的复杂标记。

例如，我想设计一个新的标记，它是一组顶点的并集，例如(只是一个例子)，两个对称的花瓣(参见 verts1 和 verts2)以及上面和下面的两条线(请参阅 verts3 和 verts4)。我还想让花瓣可能被填充(或不填充)，并且每个顶点的边缘颜色可能有不同的颜色(一个花瓣是蓝色，另一个是橙色)。我应该如何进行？

一种简单的方法是做类似的事情(对于双花瓣，左边的花瓣没有被填充，右边的花瓣被填充，请参阅下面的 verts1、verts2、verts3、verts4 的定义):

代码

x = rand(10)
y = rand(10)
verts = [verts1, verts2, verts3, verts4]
fc = ['k', 'None', 'None', 'None']
ec = ['b', 'orange', 'k', 'k']

for lverts, lfc, lec in list(zip(verts, fc, ec)) :
    scatter(x, y, marker= (lverts, 0), facecolor=lfc, edgecolor=lec, s=1000, label='My symbol')

==> 但是，由于这些是在 for 循环中完成的，因此当我执行以下操作时，它不会被视为单个标记:

legend(loc=0)

问题:我应该如何处理这个问题？ (在网上找不到答案)

欢迎提出建议!

谢谢!

顶点的定义

if 1:
    # verts1:
    size, angrad = 10., 0.
    rx = 4. * size
    theta = np.linspace(-pi / 4., pi / 4., 151)
    x = rx*np.sqrt(cos(2.*theta))*cos(theta)
    y = rx*np.sqrt(cos(2.*theta))*sin(theta)
    rotx = x * cos(angrad) + y * sin(angrad)
    roty = -x * sin(angrad) + y * cos(angrad)
    verts1 = list(zip(rotx,roty))

    # verts2:
    size, angrad = 10.,  np.pi
    rx = 4. * size
    theta = np.linspace(-pi / 4., pi / 4., 151)
    x = rx*np.sqrt(cos(2.*theta))*cos(theta)
    y = rx*np.sqrt(cos(2.*theta))*sin(theta)
    rotx = x * cos(angrad) + y * sin(angrad)
    roty = -x * sin(angrad) + y * cos(angrad)
    verts2 = list(zip(rotx,roty))

    # verts3
    verts3 = list(zip([0.,0.],[0,0.1]))

    # verts4
    verts4 = list(zip([0.,0.],[-0.1,-0.03])) 

Answer 1

关于如何创建单独的自定义图例标记存在一些问题:

• How to show shapefile label in python basemap legend?

• Create a matplotlib mpatches with a rectangle bi-colored for figure legend

• Single legend item with two lines

这个想法是在所有其他方法无法创建自定义处理程序类并使用它在图例内创建符号的情况下。

import matplotlib.pyplot as plt
import numpy as np


class Symbol(object):
    def __init__(self,fc, ec, markersize):
        size, angrad = 10., 0.
        rx = 4. * size
        theta = np.linspace(-np.pi / 4., np.pi / 4., 151)
        x = rx*np.sqrt(np.cos(2.*theta))*np.cos(theta)
        y = rx*np.sqrt(np.cos(2.*theta))*np.sin(theta)
        rotx = x * np.cos(angrad) + y * np.sin(angrad)
        roty = -x * np.sin(angrad) + y * np.cos(angrad)
        verts1 = list(zip(rotx,roty))
        # verts2:
        size, angrad = 10.,  np.pi
        rx = 4. * size
        theta = np.linspace(-np.pi / 4., np.pi / 4., 151)
        x = rx*np.sqrt(np.cos(2.*theta))*np.cos(theta)
        y = rx*np.sqrt(np.cos(2.*theta))*np.sin(theta)
        rotx = x * np.cos(angrad) + y * np.sin(angrad)
        roty = -x * np.sin(angrad) + y * np.cos(angrad)
        verts2 = list(zip(rotx,roty))
        # verts3
        verts3 = list(zip([0.,0.],[0,0.1]))
        # verts4
        verts4 = list(zip([0.,0.],[-0.1,-0.03])) 

        self.verts=[verts1,verts2,verts3,verts4]
        self.fc = fc
        self.ec = ec
        self.size=markersize
        self.group = list(zip(self.verts, self.fc, self.ec))

class SymbolHandler(object):
    def legend_artist(self, legend, orig_handle, fontsize, handlebox):

        x0, y0 = handlebox.xdescent, handlebox.ydescent
        width,height = handlebox.width, handlebox.height
        sc = []
        for lverts, lfc, lec in orig_handle.group:
            c = plt.scatter([width/2.-x0], [height/2.-y0], marker=(lverts, 0), 
                             facecolor=lfc, edgecolor=lec,s=orig_handle.size, 
                             transform=handlebox.get_transform())
            handlebox.add_artist(c)
            c.remove()
            sc.append(sc)
        return []


x = np.random.rand(4)
y = np.random.rand(4)
x2 = np.random.rand(4)
y2 = np.random.rand(4) 

fc = ['k', 'None', 'None', 'None']
ec = ['b', 'orange', 'k', 'k']
size =1000.
s = Symbol(fc,ec, size)
for lverts, lfc, lec in s.group:
    plt.scatter(x, y, marker= (lverts, 0), facecolor=lfc, edgecolor=lec, 
                s=size)


fc2 = ['crimson', 'limegreen', 'None', 'None']
ec2 = ['gold', 'gold', 'purple', 'k']
size2 =800.
s2 = Symbol(fc2,ec2, size2)
for lverts, lfc, lec in s2.group:
    plt.scatter(x2, y2, marker= (lverts, 0), facecolor=lfc, edgecolor=lec, 
                s=size2)


plt.legend([s,s2], ['label 1', "label 2"], handleheight=5, handlelength=3,
           handler_map={Symbol: SymbolHandler()})

plt.xlim(-0.3,1.3)
plt.ylim(-0.3,1.3)
plt.show()