无法使用rotate_around()围绕特定点旋转matplotlib补丁对象

Question

我正在尝试使用 rotate_around() 和 rotate_deg_around() 函数围绕特定点旋转 matplotlib 矩形补丁对象。但是，补丁始终围绕原点旋转。我不确定如何确保补丁对象围绕特定点旋转。

这里的代码如下：

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.patches as patches
import matplotlib as mpl
fig = plt.figure()
ax = fig.add_subplot(111)
ax.set_xlim(-0.05,1);ax.set_ylim(-0.05,1);
grid('on');

#Rotate rectangle patch object
ts = ax.transData
tr = mpl.transforms.Affine2D().rotate_deg_around(0.2,0.5,10)
t= ts + tr

rec0 = patches.Rectangle((0.2,0.5),0.25,0.2,alpha=0.5)
ax.add_patch(rec0)

#Rotated rectangle patch
rect1 = patches.Rectangle((0.2,0.5),0.25,0.2,color='blue',alpha=0.5,transform=t)
ax.add_patch(rect1);

#The (desired) point of rotation
ax.scatter([0.0,0.2],[0.0,0.5],c=['g','r'],zorder=10)
txt = ax.annotate('Desired point of rotation',xy=(0.2,0.5),fontsize=16,\
xytext=(0.25,0.35),arrowprops=dict(arrowstyle="->",connectionstyle="arc3,rad=-.2"))
txt2 = ax.annotate('Actual point of rotation',xy=(0.0,0.0),fontsize=16,\
xytext=(0.15,0.15),arrowprops=dict(arrowstyle="->",connectionstyle="arc3,rad=.2"))

plt.show()

下面是上面代码的输出：

我也尝试过做 translate、rotate_about_origin 和 translate_back。但是，翻译转换也不起作用。任何简单翻译的帮助/示例也将非常有用。

谢谢你。

Answer 1

您旋转的坐标不是数据坐标。你必须先转换它们，即

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.patches as patches
import matplotlib as mpl
fig = plt.figure()
ax = fig.add_subplot(111)
ax.set_xlim(-0.05,1);ax.set_ylim(-0.05,1);
plt.grid('on');

#Rotate rectangle patch object
ts = ax.transData
coords = ts.transform([0.2, 0.5])
tr = mpl.transforms.Affine2D().rotate_deg_around(coords[0], coords[1], 10)
t= ts + tr

rec0 = patches.Rectangle((0.2,0.5),0.25,0.2,alpha=0.5)
ax.add_patch(rec0)

#Rotated rectangle patch
rect1 = patches.Rectangle((0.2,0.5),0.25,0.2,color='blue',alpha=0.5,transform=t)
ax.add_patch(rect1);

#The (desired) point of rotation
ax.scatter([0.0,0.2],[0.0,0.5],c=['g','r'],zorder=10)
txt = ax.annotate('Desired point of rotation',xy=(0.2,0.5),fontsize=16,\
xytext=(0.25,0.35),arrowprops=dict(arrowstyle="->",connectionstyle="arc3,rad=-.2"))
txt2 = ax.annotate('Actual point of rotation',xy=(0.0,0.0),fontsize=16,\
xytext=(0.15,0.15),arrowprops=dict(arrowstyle="->",connectionstyle="arc3,rad=.2"))

plt.show()

编辑：

显然，该代码仅适用于交互式显示，但不适用于调整窗口大小或保存图形时。比较这两个图像：