Python在Axis('square')和set_xlim之间的相互作用

Question

对于相关图，我希望有一个光学正方形的图(以像素为单位的x和y的长度相同(，但在x和y上也有一定的轴限制。我可以分别获得这两个图中的每一个，但不能同时获得：

import matplotlib.pyplot as plt
f, (ax1, ax2) = plt.subplots(1, 2)
x = [1 , 4 , 6]
y1 = [4, 7, 9]
y2 = [20, 89, 99]
ax1.plot(x, y1, 'o')
ax2.plot(x, y2, 'o')
myXlim = [0, 8]
ax1.set_xlim(myXlim)
ax2.set_xlim(myXlim)
ax1.axis('square')
ax2.axis('square')
# limit is gone here
ax1.set_xlim(myXlim)
ax2.set_xlim(myXlim)
# square is gone here
plt.show()

如果我只使用ax1.set_xlim(myXlim)(而不是square(，那么我可以手动调整窗口大小以获得我想要的内容，但我如何自动做到这一点？

Answer 1

获取正方形子图形的一个选项是设置子图形参数，使生成的子图形自动调整为正方形。这有点涉及，因为所有的边距和间距都需要考虑在内。

import matplotlib.pyplot as plt
f, (ax1, ax2) = plt.subplots(1, 2)
x = [1 , 4 , 6]
y1 = [4, 7, 9]
y2 = [20, 89, 99]
def square_subplots(fig):
rows, cols = ax1.get_subplotspec().get_gridspec().get_geometry()
l = fig.subplotpars.left
r = fig.subplotpars.right
t = fig.subplotpars.top
b = fig.subplotpars.bottom
wspace = fig.subplotpars.wspace
hspace = fig.subplotpars.hspace
figw,figh = fig.get_size_inches()
axw = figw*(r-l)/(cols+(cols-1)*wspace)
axh = figh*(t-b)/(rows+(rows-1)*hspace)
axs = min(axw,axh)
w = (1-axs/figw*(cols+(cols-1)*wspace))/2.
h = (1-axs/figh*(rows+(rows-1)*hspace))/2.
fig.subplots_adjust(bottom=h, top=1-h, left=w, right=1-w)
ax1.plot(x, y1, 'o')
ax2.plot(x, y2, 'o')
#f.tight_layout() # optionally call tight_layout first
square_subplots(f)
plt.show()

这里的好处是可以自由缩放。缺点是，一旦图形大小发生变化，子图形大小就不再是正方形。为了克服这个缺点，还可以在图形的大小变化时注册回调

import matplotlib.pyplot as plt
f, (ax1, ax2) = plt.subplots(1, 2)
x = [1 , 4 , 6]
y1 = [4, 7, 9]
y2 = [20, 89, 99]
class SquareSubplots():
def __init__(self, fig):
self.fig = fig
self.ax = self.fig.axes[0]
self.figw,self.figh = 0,0
self.params = [self.fig.subplotpars.left,
self.fig.subplotpars.right,
self.fig.subplotpars.top,
self.fig.subplotpars.bottom,
self.fig.subplotpars.wspace,
self.fig.subplotpars.hspace]
self.rows, self.cols = self.ax.get_subplotspec().get_gridspec().get_geometry()
self.update(None)
self.cid = self.fig.canvas.mpl_connect('resize_event', self.update)

def update(self, evt):
figw,figh = self.fig.get_size_inches()
if self.figw != figw or self.figh != figh:
self.figw = figw; self.figh = figh
l,r,t,b,wspace,hspace = self.params
axw = figw*(r-l)/(self.cols+(self.cols-1)*wspace)
axh = figh*(t-b)/(self.rows+(self.rows-1)*hspace)
axs = min(axw,axh)
w = (1-axs/figw*(self.cols+(self.cols-1)*wspace))/2.
h = (1-axs/figh*(self.rows+(self.rows-1)*hspace))/2.
self.fig.subplots_adjust(bottom=h, top=1-h, left=w, right=1-w)
self.fig.canvas.draw_idle()
s = SquareSubplots(f)
ax1.plot(x, y1, 'o')
ax2.plot(x, y2, 'o')
plt.show()

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上述解决方案通过限制子图形在其网格内的空间来工作。相反的方法是，子地块的大小在某种程度上是固定的，在数据限制不同的情况下，创建具有多个轴的等宽(正方形(图的答案中会显示出来？。