用于更改为下一图像的外部触发器

Question

Rasberry pi / python的新手并试图修改一些代码：

我有以下内容，并希望使用外部触发器更改为下一张图像。

#!/usr/bin/env python
from Tkinter import *
import Image, ImageTk
import os, sys
import RPi.GPIO as GPIO

class Viewer:
    def __init__(self, master, filelist):
        GPIO.setmode(GPIO.bin)
        GPIO.setup(23, GPIO.IN, pull_up_down=GPIO.PUD.UP)
        GPIO.add_event_detect(23, GPIO.FALLING)
        self.top = master
        self.files = filelist
        self.index = 0
        #display first image
        filename = filelist[0]
        if not os.path.exists(filename):
            print "Unable to find %s" % filename
            self.top.quit()

    self.title = Label(text=os.path.basename(filename))
    self.title.pack()

    im = Image.open(filename)
    if im.format == "SPIDER":
        im = im.convert2byte()
    self.size = im.size
    self.tkimage = ImageTk.PhotoImage(im, palette=256)

    self.lbl = Label(master, image=self.tkimage)
    self.lbl.pack(side='top')

    # the button frame
    fr = Frame(master)
    fr.pack(side='top', expand=1, fill='x')
    back = Button(fr, text="back", command=lambda : self.nextframe(-1))
    back.grid(row=0, column=0, sticky="w", padx=4, pady=4)

    ilabel = Label(fr, text="image number:")
    ilabel.grid(row=0, column=1, sticky="e", pady=4)

    self.evar = IntVar()
    self.evar.set(1)
    entry = Entry(fr, textvariable=self.evar)
    entry.grid(row=0, column=2, sticky="w", pady=4)
    entry.bind('<Return>', self.getimgnum)

    next = Button(fr, text="next", command=lambda : self.nextframe(1))
    next.grid(row=0, column=3, sticky="e", padx=4, pady=4)

# image doesn't appear unless put Image.open in separate function?
# and need to use tkimage.paste, not ImageTk.PhotoImage
def getImage(self, filename):
    im = Image.open(filename)
    if im.format == "SPIDER":
        im = im.convert2byte()
    if im.size != self.size:
        print "all images must be same dimensions:"
        f1 = os.path.basename(self.files[0])
        f2 = os.path.basename(filename)
        print "%s: %s, %s : %s" % (f1, str(self.size),f2, str(im.size))
        self.top.quit()
    return im

def nextframe(self,i=1, imgnum=-1):
    if imgnum == -1:
        self.index += i
    else:
        self.index = imgnum - 1
    if self.index >= len(self.files):
        self.index = 0
    elif self.index < 0:
        self.index = len(self.files) - 1
    filename = self.files[self.index]
    if not os.path.exists(filename):
        print "Unable to find %s" % filename
        self.top.quit()
    self.title.configure(text=os.path.basename(filename))
    self.evar.set(self.index+1)

    im = self.getImage(filename)
    self.tkimage.paste(im)

def getimgnum(self, event=None):
    self.nextframe(imgnum=self.evar.get())


if __name__ == "__main__":

    if not sys.argv[1:]:
        print "Usage: viewseries.py images*"
        sys.exit()
filelist = sys.argv[1:]

root = Tk()
app = Viewer(root, filelist)
root.mainloop()

----------------------------------------------- ------------------------

以下是代码的简单版本：

import Tkinter
import Image
import ImageTk
import Rpi.GPIO as GPIO

GPIO.setmode(GPIO.BCM)
GPIO.setup(23, GPIO.IN, pull_up_down=GPIO.PUD_UP)


trig =1

def ChangeImage():
    global tkpi
    global trig
    trig = trig + 1
    image = Image.open("home/pi/Desktop/" + str(trig) + ".gif")
    tkpi = ImageTk.PhotoImage(image)
    label_image = Tkinter.Label (root, image=tkpi)
    root.bind(GPIO.wait_for_edge(23, GPIO.FALLING), changeImage)
    root.attributes("-fullscreen", True)
    #root.after(500, changeImage)

tkpi = None
root = Tkinter.Tk()
changeImage()
root.mainloop()

Answer 1

我明白了。

import Tkinter
import Image
import ImageTk
import Rpi.GPIO as GPIO

GPIO.setmode(GPIO.BCM)
GPIO.setup(23, GPIO.IN, pull_up_down=GPIO.PUD_UP)


trig =1

def ChangeImage(self):
    global tkpi
    global trig
    trig = trig + 1
    image = Image.open("home/pi/Desktop/" + str(trig) + ".gif")
    tkpi = ImageTk.PhotoImage(image)
    label_image = Tkinter.Label (root, image=tkpi)
    root.bind(GPIO.add_event_detect(23, GPIO.FALLING callback=changeImage)
    root.attributes("-fullscreen", True)
    #root.after(500, changeImage)

tkpi = None
root = Tkinter.Tk()
changeImage(None)
root.mainloop()

Answer 2

我对学校的RPi知识有所了解，当我们使用GertBoard上的按钮（带LED按钮的RB扩展板等）时，我们使用了添加事件检测

import Tkinter
import Image
import ImageTk
import Rpi.GPIO as GPIO

GPIO.setmode(GPIO.BCM)
GPIO.setup(23, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.add_event_detect(23, GPIO.FALLING)


trig = 0 #are you sure you dont want this 0 
         #first since you increment it before adressing the image number
         #keep it in mind
         #unless picture numbering starts with 2

def ChangeImage():
    global tkpi
    global trig
    trig = trig + 1 #if you set the initial value to one below this line it will be 2 for the first time. Keep it in mind
    image = Image.open("home/pi/Desktop/" + str(trig) + ".gif")
    tkpi = ImageTk.PhotoImage(image)
    label_image = Tkinter.Label (root, image=tkpi)
    root.attributes("-fullscreen", True)

    GPIO.add_event_callback(23, ChangeImage)


tkpi = None #I'm quite sure this is not needed since you overwrite it when needed
root = Tkinter.Tk()
changeImage()
root.mainloop()

我们使用此处的信息： http://sourceforge.net/p/raspberry-gpio-python/wiki/Inputs/