我正在使用 matplotlib 绘制一些我希望用箭头(距离标记)注释的数据。这些箭头应偏移几个点,以免与绘制的数据重叠:
import matplotlib.pyplot as plt
import matplotlib.transforms as transforms
fig, ax = plt.subplots()
x = [0, 1]
y = [0, 0]
# Plot horizontal line
ax.plot(x, y)
dy = 5/72
offset = transforms.ScaledTranslation(0, dy, ax.get_figure().dpi_scale_trans)
verttrans = ax.transData+offset
# Plot horizontal line 5 points above (works!)
ax.plot(x, y, transform = verttrans)
# Draw arrow 5 points above line (doesn't work--not vertically translated)
ax.annotate("", (0,0), (1,0),
size = 10,
transform=verttrans,
arrowprops = dict(arrowstyle = '<|-|>'))
plt.show()
有没有办法让 ax.annotate()
绘制的线偏移 X 点?我希望使用绝对坐标(例如,点或英寸)而不是数据坐标,因为轴限制很容易发生变化。
谢谢!
最佳答案
下面的代码完成了我想要的。它使用 ax.transData 和 figure.get_dpi():
import matplotlib.pyplot as plt
import matplotlib.transforms as transforms
fig, ax = plt.subplots()
x = [0, 1]
y = [0, 0]
ax.plot(x, y)
dy = 5/72
i = 1 # 0 for dx
tmp = ax.transData.transform([(0,0), (1,1)])
tmp = tmp[1,i] - tmp[0,i] # 1 unit in display coords
tmp = 1/tmp # 1 pixel in display coords
tmp = tmp*dy*ax.get_figure().get_dpi() # shift pixels in display coords
ax.plot(x, y)
ax.annotate("", [0,tmp], [1,tmp],
size = 10,
arrowprops = dict(arrowstyle = '<|-|>'))
plt.show()
关于python - 如何通过 X 点偏移 matplotlib 中的线,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23839468/