matplotlib & pandas

Python/matplotlab/gallery/pyplots/annotate_transform.md

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+# 注释变换
+
+此示例显示如何使用不同的坐标系进行注释。 有关注释功能的完整概述，另请参阅[注释教程](https://matplotlib.org/tutorials/text/annotations.html)。
+
+```python
+import numpy as np
+import matplotlib.pyplot as plt
+
+x = np.arange(0, 10, 0.005)
+y = np.exp(-x/2.) * np.sin(2*np.pi*x)
+
+fig, ax = plt.subplots()
+ax.plot(x, y)
+ax.set_xlim(0, 10)
+ax.set_ylim(-1, 1)
+
+xdata, ydata = 5, 0
+xdisplay, ydisplay = ax.transData.transform_point((xdata, ydata))
+
+bbox = dict(boxstyle="round", fc="0.8")
+arrowprops = dict(
+    arrowstyle = "->",
+    connectionstyle = "angle,angleA=0,angleB=90,rad=10")
+
+offset = 72
+ax.annotate('data = (%.1f, %.1f)'%(xdata, ydata),
+            (xdata, ydata), xytext=(-2*offset, offset), textcoords='offset points',
+            bbox=bbox, arrowprops=arrowprops)
+
+
+disp = ax.annotate('display = (%.1f, %.1f)'%(xdisplay, ydisplay),
+            (xdisplay, ydisplay), xytext=(0.5*offset, -offset),
+            xycoords='figure pixels',
+            textcoords='offset points',
+            bbox=bbox, arrowprops=arrowprops)
+
+
+plt.show()
+```
+
+![注释变换示例](https://matplotlib.org/_images/sphx_glr_annotate_transform_001.png)
+
+## 参考
+
+此示例中显示了以下函数，方法，类和模块的使用：
+
+```python
+import matplotlib
+matplotlib.transforms.Transform.transform_point
+matplotlib.axes.Axes.annotate
+matplotlib.pyplot.annotate
+```
+
+## 下载这个示例
+            
+- [下载python源码: annotate_transform.py](https://matplotlib.org/_downloads/annotate_transform.py)
+- [下载Jupyter notebook: annotate_transform.ipynb](https://matplotlib.org/_downloads/annotate_transform.ipynb)