Matplotlib Fig-level Text and Annotation Functions

Matplotlib 参考文档 Matplotlib Reference Documentation

In addition to text() and annotate(), Matplotlib also provides Figure-level text functions, table addition, and arrow drawing.

Function Overview

Function	Description
figtext()	Add text at Figure level (not Axes)
figlegend()	Add legend at Figure level (across Axes)
table()	Add a table to Axes
arrow()	Add a simple arrow

figtext() - Figure-level Text

matplotlib.pyplot.figtext(x, y, s, fontdict=None, **kwargs)

Similar to text(), but the coordinate system is Figure coordinates (0-1), not data coordinates.

Example

import matplotlib.pyplot as plt
import numpy as np

fig, ax = plt.subplots(figsize=(8, 5))
ax.plot([0, 1], [0, 1], 'steelblue')
ax.set_title('Axes-level (text vs figtext)')

# Axes-level text (data coordinates)
ax.text(0.3, 0.7, 'Axes text (data coords)',
fontsize=12, color='blue')

# Figure-level text (Figure relative coordinates 0-1)
plt.figtext(0.5, 0.02,
'Figure text at bottom center (Figure coords)',
ha='center', fontsize=10, color='gray')
plt.figtext(0.02, 0.95,
'Top left',
ha='left', va='top',
fontsize=12, fontweight='bold', color='red')

plt.show()

figlegend() - Figure-level Legend

matplotlib.pyplot.figlegend(*args, **kwargs)

When multiple Axes need to share a legend, figlegend() can place the legend at the Figure level.

Example

import matplotlib.pyplot as plt
import numpy as np

x = np.linspace(0, 10, 100)

fig, (ax1, ax2) = plt.subplots(1, 2, figsize=(10, 4),
layout='constrained')

# Draw the same two curves on each Axes, but do not add separate legends
ax1.plot(x, np.sin(x), 'b-', label='sin(x)')
ax1.plot(x, np.cos(x), 'r--', label='cos(x)')
ax1.set_title('Plot 1')

ax2.plot(x, np.sin(x), 'b-', label='sin(x)')
ax2.plot(x, np.cos(x), 'r--', label='cos(x)')
ax2.set_title('Plot 2')

# Figure-level legend (placed at the top outside the Figure)
fig.legend(loc='outside upper center', ncol=2,
fontsize=11, frameon=True)

plt.show()

table() - Add a Table to Axes

matplotlib.pyplot.table(cellText=None, cellColours=None,
    cellLoc='right', colWidths=None, rowLabels=None,
    rowColours=None, rowLoc='left', colLabels=None,
    colColours=None, colLoc='center', loc='bottom',
    bbox=None, edges='closed', **kwargs)

Example

import matplotlib.pyplot as plt
import numpy as np

# Data to display
data = [[85, 90, 78, 92],
[76, 88, 82, 85],
[90, 93, 88, 95]]
row_labels = ['Student A', 'Student B', 'Student C']
col_labels = ['Math', 'English', 'Science', 'History']

fig, ax = plt.subplots(figsize=(8, 4), layout='constrained')

# Draw comparison chart
x = np.arange(len(col_labels))
for i, (row, label) in enumerate(zip(data, row_labels)):
ax.plot(x, row, 'o-', label=label, markersize=8)

ax.set_xticks(x)
ax.set_xticklabels(col_labels)
ax.set_title('Student Scores')
ax.legend()
ax.grid(True, alpha=0.3)

# Add table below the chart
table = ax.table(cellText=data,
rowLabels=row_labels,
colLabels=col_labels,
cellLoc='center',
loc='bottom',
bbox=[0, -0.35, 1, 0.25]) # [left, bottom, width, height]

plt.show()

arrow() - Add Arrow

matplotlib.pyplot.arrow(x, y, dx, dy, **kwargs)

arrow() is a shortcut for adding simple arrows. For complex arrow annotations, annotate() is recommended.

Example

import matplotlib.pyplot as plt
import numpy as np

fig, ax = plt.subplots(figsize=(7, 5), layout='constrained')

# Draw coordinate system
ax.spines[['left', 'bottom']].set_position(('data', 0))
ax.spines[['top', 'right']].set_visible(False)
ax.set_xlim(-1, 5)
ax.set_ylim(-1, 5)

# Various arrows
ax.arrow(0, 0, 3, 0, head_width=0.2, head_length=0.2,
fc='red', ec='red', label='Right 3 units')
ax.arrow(0, 0, 0, 3, head_width=0.2, head_length=0.2,
fc='blue', ec='blue', label='Up 3 units')
ax.arrow(0, 0, 2, 2, head_width=0.2, head_length=0.2,
fc='green', ec='green', label='Diagonal')

ax.set_title('arrow() - Simple Arrows')
ax.legend()
ax.grid(True, alpha=0.3)
plt.show()

Matplotlib 参考文档 Matplotlib Reference Documentation

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