Question

我正在尝试使用鼠标在图像上绘制点。问题：图像出现，但是当我点击鼠标时，没有绘制任何内容（即使我点击了几次）。

我的Python版本是Python 2.7，带有Anaconda和IPython控制台。我在运行脚本之前在Ipython控制台中键入％pylab。

这是我的代码：

import numpy as np
from matplotlib import pyplot as plt 
#Some code here [. . .]

fig, ax = plt.subplots(1)
ax.imshow(img, interpolation = 'bicubic')
'''preventing plot from rescaling image:'''
ax.set_xlim([0.0, img.shape[1]])
ax.set_ylim([img.shape[0], 0.0])
ax.hold(True)
ax.autoscale = False
#ax.plot(100,100, 'ro')  # This works

class MouseMonitor:
    flag = True
    x = 0.
    y = 0.  
    fig = None
    axes = None

    def __init__(self, fig, ax):
        self.axes = ax
        self.fig = fig
    def __call__(self, event):
        if self.flag:
            print('({}, {})'.format(event.xdata, event.ydata))
            self.flag = False
        else:
            d = np.linalg.norm([event.xdata - self.x, event.ydata - self.y])
            print('({}, {})\n\n distance between points: {} m\n\n-------------------\n'.format(event.xdata, event.ydata, d))
            self.flag = True                       
        self.x = event.xdata
        self.y = event.ydata
        self.axes.plot(self.y, self.x, 'ro', linewidth = 5) #This don't work

mouse = MouseMonitor(fig, ax)

cid = fig.canvas.mpl_connect('button_press_event', mouse)

Answer 1

来自tcaswell评论的答案：

将self.axes.figure.canvas.draw_idle（）调用添加到回调中。

使用鼠标在Python中绘制图像上的点，使用Matplotlib

1 个答案: