利用matplotlib为图片上添加触发事件进行交互

# coding=utf-8
from matplotlib import pyplot as plt
import cv2

def on_press(event):
 if event.inaxes == None:
  print "none"
  return 
 #在鼠标的当前位置绘制一个点
 ax.scatter(event.xdata, event.ydata）
 #更新画板
 fig.canvas.draw()

if __name__ == "__main__":
 fileN = r'./0107_1.3.6.1.4.1.14519.5.2.1.6279.6001.263660956768649083933159084365.bmp'
 img = cv2.imread(fileN)
 cv2.imshow('img',img)
 fig = py.figure()
 fig.canvas.mpl_connect("button_press_event", on_press) 
 ax = fig.add_subplot(121)
 ax1 = fig.add_subplot(122)
 ax.imshow(img)
 ax1.imshow(img)
 plt.axis("off")
 plt.show()

fig.canvas.mpl_connect("button_press_event", on_press)#在这个figure上加点击事件，点击后的情况在自己写的on_press()方法里 
def on_press(event): 
  event.inaxes.figure.canvas.draw()#用于图片刷新 
  event.x#事件的坐标用于其他按钮点击和figure点击发生冲突时判断返回 
  event.xdata,event.ydata#鼠标点击的位置，与上面那个坐标表示形式不同 

if __name__ == "__main__":
 fileN = r'./0107_1.3.6.1.4.1.14519.5.2.1.6279.6001.263660956768649083933159084365.bmp'
 img = cv2.imread(fileN)
 cv2.imshow('img',img)
 fig = py.figure()
 fig.canvas.mpl_connect("button_press_event", on_press) 
 ax = fig.add_subplot(121)
 ax1 = fig.add_subplot(122)
 ax.imshow(img)
 ax1.imshow(img)
 #关闭自动尺度适配
 ax.set_autoscale_on(False) 
 plt.axis("off")
 plt.show()

ax.scatter(x,y,c='k',s=25,alpha=1.0,marker='o')
#T:散点的颜色
#s：散点的大小
#alpha:是透明程度

def on_key(event, arg1, arg2, arg3):
 pass
canvas.mpl_connect('key_press_event', lambda event: on_key(event, plt1, plt2, plt3))

def on_key(event, args_list):
 pass
fig.canvas.mpl_connect('key_press_event', lambda event: on_key(event, [plt1, plt2, plt3]))

from matplotlib.patches import Circle

fig = plt.figure()
ax = fig.add_subplot(111)
cir = Circle(xy = (event.xdata, event.ydata),facecolor = 'black', edgecolor='black',radius=10, alpha=1.0) 
ax.add_patch(cir)