matplotlib & pandas

Python/matplotlab/gallery/widgets/rectangle_selector.md

@@ -0,0 +1,61 @@
+# 矩形选择器
+
+在某处鼠标点击，将鼠标移动到某个目的地，然后释放按钮。 此类提供单击和释放事件，并从点击点到实际鼠标位置（在相同轴内）绘制一条线或一个框，直到释放按钮。 在方法'self.ignore()'中，检查来自eventpress和eventrelease的按钮是否相同。
+
+![矩形选择器示例](https://matplotlib.org/_images/sphx_glr_rectangle_selector_001.png)
+
+输出：
+
+```python
+click  -->  release
+```
+
+```python
+from matplotlib.widgets import RectangleSelector
+import numpy as np
+import matplotlib.pyplot as plt
+
+
+def line_select_callback(eclick, erelease):
+    'eclick and erelease are the press and release events'
+    x1, y1 = eclick.xdata, eclick.ydata
+    x2, y2 = erelease.xdata, erelease.ydata
+    print("(%3.2f, %3.2f) --> (%3.2f, %3.2f)" % (x1, y1, x2, y2))
+    print(" The button you used were: %s %s" % (eclick.button, erelease.button))
+
+
+def toggle_selector(event):
+    print(' Key pressed.')
+    if event.key in ['Q', 'q'] and toggle_selector.RS.active:
+        print(' RectangleSelector deactivated.')
+        toggle_selector.RS.set_active(False)
+    if event.key in ['A', 'a'] and not toggle_selector.RS.active:
+        print(' RectangleSelector activated.')
+        toggle_selector.RS.set_active(True)
+
+
+fig, current_ax = plt.subplots()                 # make a new plotting range
+N = 100000                                       # If N is large one can see
+x = np.linspace(0.0, 10.0, N)                    # improvement by use blitting!
+
+plt.plot(x, +np.sin(.2*np.pi*x), lw=3.5, c='b', alpha=.7)  # plot something
+plt.plot(x, +np.cos(.2*np.pi*x), lw=3.5, c='r', alpha=.5)
+plt.plot(x, -np.sin(.2*np.pi*x), lw=3.5, c='g', alpha=.3)
+
+print("\n      click  -->  release")
+
+# drawtype is 'box' or 'line' or 'none'
+toggle_selector.RS = RectangleSelector(current_ax, line_select_callback,
+                                       drawtype='box', useblit=True,
+                                       button=[1, 3],  # don't use middle button
+                                       minspanx=5, minspany=5,
+                                       spancoords='pixels',
+                                       interactive=True)
+plt.connect('key_press_event', toggle_selector)
+plt.show()
+```
+
+## 下载这个示例
+            
+- [下载python源码: rectangle_selector.py](https://matplotlib.org/_downloads/rectangle_selector.py)
+- [下载Jupyter notebook: rectangle_selector.ipynb](https://matplotlib.org/_downloads/rectangle_selector.ipynb)