考虑这个例子。其中我在 cm 中精确指定我的轴的尺寸。matplotlib 以英寸为单位工作,所以我转换为英寸。然后我也用特定的 dpi (128) 保存它,以便它与我的显示器中的设计尺寸相匹配。这当然因每个显示器而异。我发现通过反复试验,即使可能有其他方法。好吧这里的代码:

left_margin = 1.   # cm
right_margin = 1.  # cm
figure_width = 10. # cm
figure_height = 7. # cm
top_margin = 1.    # cm
bottom_margin = 1. # cm
box_width = left_margin + figure_width + right_margin   # cm
box_height = top_margin + figure_height + bottom_margin # cm
cm2inch = 1/2.54 # inch per cm
# specifying the width and the height of the box in inches
fig = figure(figsize=(box_width*cm2inch,box_height*cm2inch))
ax = fig.add_subplot(111)
ax.plot([1,2,3])
fig.subplots_adjust(left   = left_margin / box_width,
                    bottom = bottom_margin / box_height,
                    right  = 1. - right_margin / box_width,
                    top    = 1. - top_margin   / box_height,
                    )
fig.savefig('ten_x_seven_cm.png', dpi=128)
# dpi = 128 is what works in my display for matching the designed dimensions.

将此添加到 @ pablo reyes 的答案中，检查打印机是否处于 100 ％，并且非常接近；

ax.set_ylim(0,7)
ax.set_xlim(0,10)
ax.plot([0.5, 1.5],[0.25, 0.25],label='One cm?')
ax.plot([6,6],[1,2], label='One cm?')
ax.legend()

我们强迫轴是我们知道的大小，我们使它的数据转换与现实世界相匹配，我们可以“打印一把尺子”。

使用fig.add_axes的另一种方法非常准确。我也包括 1 厘米的网格。

import matplotlib.pyplot as plt
import matplotlib as mpl
# This example fits a4 paper with 5mm margin printers
# figure settings
figure_width = 28.7 # cm
figure_height = 20 # cm
left_right_margin = 1 # cm
top_bottom_margin = 1 # cm
# Don't change
left   = left_right_margin / figure_width # Percentage from height
bottom = top_bottom_margin / figure_height # Percentage from height
width  = 1 - left*2
height = 1 - bottom*2
cm2inch = 1/2.54 # inch per cm
# specifying the width and the height of the box in inches
fig = plt.figure(figsize=(figure_width*cm2inch,figure_height*cm2inch))
ax = fig.add_axes((left, bottom, width, height))
# limits settings (important)
plt.xlim(0, figure_width * width)
plt.ylim(0, figure_height * height)
# Ticks settings
ax.xaxis.set_major_locator(mpl.ticker.MultipleLocator(5))
ax.xaxis.set_minor_locator(mpl.ticker.MultipleLocator(1))
ax.yaxis.set_major_locator(mpl.ticker.MultipleLocator(5))
ax.yaxis.set_minor_locator(mpl.ticker.MultipleLocator(1))
# Grid settings
ax.grid(color="gray", which="both", linestyle=':', linewidth=0.5)
# your Plot (consider above limits)
ax.plot([1,2,3,5,6,7,8,9,10,12,13,14,15,17])
# save figure ( printing png file had better resolution, pdf was lighter and better on screen)
plt.show()
fig.savefig('A4_grid_cm.png', dpi=1000)
fig.savefig('tA4_grid_cm.pdf')

Results: