非正交图中的等值线图不旋转

Question

在这里您可以看到一个示例，其中我尝试在现有图中添加等高线图。我想用 grid_helper 旋转 y 轴的“水平”线。在第一张图中，您可以看到 y 轴的水平线在没有 grid_helper 的情况下是正交的。

import numpy as np
import matplotlib.pyplot as plt
from mpl_toolkits.axisartist.grid_helper_curvelinear import GridHelperCurveLinear
from mpl_toolkits.axisartist import Subplot

# Define the range of x and y
x = np.linspace(0, 30, 100)
y = np.linspace(0, 30, 100)

# Generate a meshgrid
X, Y = np.meshgrid(x, y)

# Define z as a function of x and y
def z(x, y):
    return  x + y

# Use the grid_helper tool in order to turn the y axis from orthogonal to non-orthogonal
def tr(x, y):
    x, y = np.asarray(x), np.asarray(y)
    return x, -2.5 * x + y

def inv_tr(x, y):
    x, y = np.asarray(x), np.asarray(y)
    return 4 / 3 * x + -1 / 3 * y, x + 4 / 3 * y

grid_helper = GridHelperCurveLinear((tr, inv_tr))

# Adding a subplot and create a contour plot with X,Y and z(X,Y)
# This would be the contour plot in the figure with an orthogonal y-axis
fig = plt.figure(figsize=(25, 15))
ax1 = Subplot(fig, 1, 1, 1)

fig.add_subplot(ax1)
ax1.grid(visible=True, which="both", axis="y", linewidth=1)

ax1.contour(X, Y, z(X, Y))

plt.show()

创建的图应如下所示：

[正交系统中的等高线图]

现在我想要通过在我的子图中实现网格助手来在非正交系统中添加等高线图。

最后几行应如下所示：

fig = plt.figure(figsize=(25, 15))

#Here I implement the grid_helper in the subplot
ax1 = Subplot(fig, 1, 1, 1, grid_helper=grid_helper)

fig.add_subplot(ax1)
ax1.grid(visible=True, which="both", axis="y", linewidth=1)

ax1.contour(X, Y, z(X, Y))

plt.show()

第二个图如下所示：

[非-prthogonal system]

如您所见，grid_helper 对 y 轴的“水平”线有影响，但不会旋转等高线图的线。我的问题是，是否有任何方法可以像我对 y 轴线所做的那样旋转等高线图线。