创建带有实心正方形和加号的自定义标记

Question

我想创建具有自定义标记样式的线图。我特别想要一个带有加号或乘积符号的正方形（填充/未填充）。这个怎么做。下面的代码不起作用

import matplotlib.pyplot as plt
import matplotlib.patches as mpatches
import numpy as np

# Sample data
x = np.linspace(0, 10, 100)
y = np.sin(x)

# Create a figure and axis
fig, ax = plt.subplots()

# Define the custom marker as a combination of a filled square and a plus symbol
def custom_marker():
    square = mpatches.Rectangle((-0.5, -0.5), 1, 1, linewidth=0, edgecolor='none', facecolor='red', zorder=2)
    plus = plt.Line2D([0, 0], [-0.4, 0.4], color='white', linewidth=2, zorder=3)
    plus2 = plt.Line2D([-0.4, 0.4], [0, 0], color='white', linewidth=2, zorder=3)
    return [square, plus, plus2]

# Create a scatter plot with the custom marker style
ax.scatter(x, y, label="Data", marker=custom_marker()[0], c='blue', s=30)

# Customize the legend with the same custom marker
legend_marker = custom_marker()
ax.legend(handles=legend_marker, labels=["Custom Marker"])

# Display the plot
plt.show()

Answer 1

绘制两次怎么样？它似乎有效，并且您可以通过这种方式有更多选择：

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 6.28, 20)
y = np.sin(x)

plt.plot(
    x,
    y,
    linestyle='-',
    color='c',
    marker='s',
    markersize=8,
    markeredgewidth=1,
    markeredgecolor='b',
    markerfacecolor='orange',
)
plt.plot(
    x,
    y,
    linestyle=' ',
    color='c',
    marker='+',
    markersize=8,
    markeredgewidth=1,
    markeredgecolor='b',
    markerfacecolor='orange',
)
plt.show()

或者你可以使用这个来获得没有任何面部颜色的正方形：

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 6.28, 20)
y = np.sin(x)

plt.plot(
    x,
    y,
    linestyle='-',
    color='#00a2ff',
    marker='+',
    markersize=8,
    markeredgewidth=2,
    markeredgecolor='#bc00ca',
)
plt.plot(
    x,
    y,
    linestyle=' ',
    marker='s',
    markersize=12,
    markeredgewidth=1,
    markeredgecolor='b',
    markerfacecolor='none',
    #alpha=0.5,
)
plt.show()

或者给markerfacecolor一个值，然后打开alpha来改变它的不透明度。

更新（在您提到图例问题之后）

既然你说填充或未填充，那么这里是未填充的：

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 6.28, 20)
y = np.sin(x)

plt.plot(
    x,
    y,
    linestyle="--",
    color="r",
    marker="$\\boxplus$",
    markerfacecolor="r",
    markersize="8",
    markeredgewidth="0.1",
)
plt.plot(
    x,
    y * 2,
    linestyle=":",
    color="b",
    marker="$\\boxtimes$",
    markerfacecolor="b",
    markersize="8",
    markeredgewidth="0.1",
)
plt.legend(["R", "B"])
plt.show()