光标演示

此示例显示如何使用matplotlib提供数据游标。 它使用matplotlib来绘制光标并且可能很慢，因为这需要在每次鼠标移动时重新绘制图形。

使用本机GUI绘图可以更快地进行镜像，就像在wxcursor_demo.py中一样。

mpldatacursor和mplcursors第三方包可用于实现类似的效果。参看这个：

https://github.com/joferkington/mpldatacursor https://github.com/anntzer/mplcursors

  1. import matplotlib.pyplot as plt
  2. import numpy as np
  5. class Cursor(object):
  6.     def __init__(self, ax):
  7.         self.ax = ax
  8.         self.lx = ax.axhline(color='k')  # the horiz line
  9.         self.ly = ax.axvline(color='k')  # the vert line
  11.         # text location in axes coords
  12.         self.txt = ax.text(0.7, 0.9, '', transform=ax.transAxes)
  14.     def mouse_move(self, event):
  15.         if not event.inaxes:
  16.             return
  18.         x, y = event.xdata, event.ydata
  19.         # update the line positions
  20.         self.lx.set_ydata(y)
  21.         self.ly.set_xdata(x)
  23.         self.txt.set_text('x=%1.2f, y=%1.2f' % (x, y))
  24.         plt.draw()
  27. class SnaptoCursor(object):
  28.     """
  29.     Like Cursor but the crosshair snaps to the nearest x,y point
  30.     For simplicity, I'm assuming x is sorted
  31.     """
  33.     def __init__(self, ax, x, y):
  34.         self.ax = ax
  35.         self.lx = ax.axhline(color='k')  # the horiz line
  36.         self.ly = ax.axvline(color='k')  # the vert line
  37.         self.x = x
  38.         self.y = y
  39.         # text location in axes coords
  40.         self.txt = ax.text(0.7, 0.9, '', transform=ax.transAxes)
  42.     def mouse_move(self, event):
  44.         if not event.inaxes:
  45.             return
  47.         x, y = event.xdata, event.ydata
  49.         indx = min(np.searchsorted(self.x, [x])[0], len(self.x) - 1)
  50.         x = self.x[indx]
  51.         y = self.y[indx]
  52.         # update the line positions
  53.         self.lx.set_ydata(y)
  54.         self.ly.set_xdata(x)
  56.         self.txt.set_text('x=%1.2f, y=%1.2f' % (x, y))
  57.         print('x=%1.2f, y=%1.2f' % (x, y))
  58.         plt.draw()
  60. t = np.arange(0.0, 1.0, 0.01)
  61. s = np.sin(2 * 2 * np.pi * t)
  62. fig, ax = plt.subplots()
  64. # cursor = Cursor(ax)
  65. cursor = SnaptoCursor(ax, t, s)
  66. plt.connect('motion_notify_event', cursor.mouse_move)
  68. ax.plot(t, s, 'o')
  69. plt.axis([0, 1, -1, 1])
  70. plt.show()

下载这个示例