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

输出：

  1. click  -->  release
  1. from matplotlib.widgets import RectangleSelector
  2. import numpy as np
  3. import matplotlib.pyplot as plt
  6. def line_select_callback(eclick, erelease):
  7.     'eclick and erelease are the press and release events'
  8.     x1, y1 = eclick.xdata, eclick.ydata
  9.     x2, y2 = erelease.xdata, erelease.ydata
  10.     print("(%3.2f, %3.2f) --> (%3.2f, %3.2f)" % (x1, y1, x2, y2))
  11.     print(" The button you used were: %s %s" % (eclick.button, erelease.button))
  14. def toggle_selector(event):
  15.     print(' Key pressed.')
  16.     if event.key in ['Q', 'q'] and toggle_selector.RS.active:
  17.         print(' RectangleSelector deactivated.')
  18.         toggle_selector.RS.set_active(False)
  19.     if event.key in ['A', 'a'] and not toggle_selector.RS.active:
  20.         print(' RectangleSelector activated.')
  21.         toggle_selector.RS.set_active(True)
  24. fig, current_ax = plt.subplots()                 # make a new plotting range
  25. N = 100000                                       # If N is large one can see
  26. x = np.linspace(0.0, 10.0, N)                    # improvement by use blitting!
  28. plt.plot(x, +np.sin(.2*np.pi*x), lw=3.5, c='b', alpha=.7)  # plot something
  29. plt.plot(x, +np.cos(.2*np.pi*x), lw=3.5, c='r', alpha=.5)
  30. plt.plot(x, -np.sin(.2*np.pi*x), lw=3.5, c='g', alpha=.3)
  32. print("\n      click  -->  release")
  34. # drawtype is 'box' or 'line' or 'none'
  35. toggle_selector.RS = RectangleSelector(current_ax, line_select_callback,
  36.                                        drawtype='box', useblit=True,
  37.                                        button=[1, 3],  # don't use middle button
  38.                                        minspanx=5, minspany=5,
  39.                                        spancoords='pixels',
  40.                                        interactive=True)
  41. plt.connect('key_press_event', toggle_selector)
  42. plt.show()

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