初级cnn研究辅助：python的matplotlib显示图片 之 按钮和触发事件

图片点击触发事件

点击左侧图片，显示右侧图片，并在你点击的位置画点。

from matplotlib import pyplot as py
from matplotlib.widgets import Button,RadioButtons
import Image
def on_press(event):
    if event.inaxes == None:
        print "none"
        return 
    fig = event.inaxes.figure
    ax = fig.add_subplot(122)
    img_gray = Image.open("./Alex.jpg").convert("L")
    ax.imshow(img_gray, cmap="gray")
    print event.x
    ax1.scatter(event.xdata, event.ydata)
    py.axis("off")
    fig.canvas.draw()
if __name__ == "__main__":
    img = Image.open("./Alex.jpg")
    fig = py.figure()
    fig.canvas.mpl_connect("button_press_event", on_press) 
    ax1 = fig.add_subplot(121)   
    ax1.imshow(img)
    py.axis("off")
    py.show()

效果：

解释：

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

普通按钮触发事件

from matplotlib import pyplot as py
from matplotlib.widgets import Button,RadioButtons
import Image
def on_press(event):
    if event.inaxes == None:
        print "none"
        return 
    fig = event.inaxes.figure
    ax = fig.add_subplot(122)
    img_gray = Image.open("./Alex.jpg").convert("L")
    ax.imshow(img_gray, cmap="gray")
    print event.x
    ax1.scatter(event.xdata, event.ydata)
    py.axis("off")
    fig.canvas.draw()
def button_press(event):
    print 'button is pressed!'
def draw_button():
    global button#must global
    point = py.axes([0.3,0.03,0.1,0.03])
    button = Button(point, "click me")
    button.on_clicked(button_press)
if __name__ == "__main__":
    img = Image.open("./Alex.jpg")
    fig = py.figure()
    draw_button()
    fig.canvas.mpl_connect("button_press_event", on_press) 
    ax1 = fig.add_subplot(121)   
    ax1.imshow(img)
    py.axis("off")
    py.show()

效果：

点击按钮，控制台输出“button is pressed!”

注解：

buttonax = plt.axes([0.8,0.03,0.05,0.03])#按钮的位置大小
button = Button(buttonax, "i'am a button")#按钮
button.on_clicked(save)#按钮的点击，save()是自己定议的点击后的事件
def save(event):
    print  'i am press'

RadioButton

def button_press(event):
    print 'button is pressed!'
def radio_press(label):
    print 'select: ',label
    radiobutton.set_active(0)
def draw_button():
    global button#must global
    global radiobutton
    print 'button'
    point = py.axes([0.2,0.03,0.1,0.03])
    button = Button(point, "click me")
    button.on_clicked(button_press)
    point_two = py.axes([0.6, 0.03, 0.2, 0.05])
    radiobutton = RadioButtons(point_two, ("select me", "or me"))
    radiobutton.on_clicked(radio_press)

if __name__ == "__main__":
    img = Image.open("./Alex.jpg")
    fig = py.figure()
    draw_button()
    fig.canvas.mpl_connect("button_press_event", on_press) 
    ax1 = fig.add_subplot(121)   
    ax1.imshow(img)
    py.axis("off")
    py.show()

效果：

注解：

radiobutton.set_active(0)#"DIFFERENT"被选择
def select(label):
      print "label"#label is "DIFFERENT" or "SAME"

然后你可能会发现点击右侧按钮时也会触发右侧出现图片，这该怎么办呢？

在一的例子中有event.x就是干这个用的，通过判断这个值判断鼠标点击的位置。但是每人的电脑不同，结果不同。