Tkinter动画不起作用

Question

我试图从我的gif图像显示动画.从我之前的问题,我发现Tkinter不会自动为图像制作动画.我的Tk界面显示图像的第一帧,当我点击按钮播放动画时,它什么也没做.这可能与与按钮关联的命令有关.这是代码:

from Tkinter import *
import Tkinter

root = Tk()

photo_path = "/users/zinedine/downloads/091.gif"
photo = PhotoImage(
    file = photo_path
    )

def run():
    frame = 1
    while True:
        try:
            photo = PhotoImage(
                file = photo_path,
                format = "gif - {}".format(frame)
                )
            frame = frame + 1

        except Exception: # This because I don't know what exception it would raise
            frame = 1
            break

picture = Label(image = photo)
picture.pack()
picture.configure(run())

animate = Button(
    root,
    text = "animate",
    command = run()
    )
animate.pack()

root.geometry("250x250+100+100")
root.mainloop()

Answer 1

您可以使用通用Tk窗口小部件after()方法来安排函数在以毫秒为单位指定的延迟后运行.这只发生一次,因此通常函数本身也会调用after()使进程永久化.

在下面的代码中,定义了一个自定义AnimatedGif容器类,它在列表中分别加载和保存动画序列的所有帧,允许使用[]索引语法对它们进行快速(随机)访问.它使用照片Tk手册页-index indexvalue上提到的图像格式子选项从文件中读取单个帧.

我从动画库网站上获得了如下所示的测试图像.

以下是最初启动时的外观.

您应该能够使用相同的技术为多个图像或附加到其他类型的窗口小部件(例如Button和Canvas实例)的图像设置动画.

try:
    from tkinter import *
except ImportError:
    from Tkinter import *  # Python 2


class AnimatedGif(object):
    """ Animated GIF Image Container. """
    def __init__(self, image_file_path):
        # Read in all the frames of a multi-frame gif image.
        self._frames = []

        frame_num = 0  # Number of next frame to read.
        while True:
            try:
                frame = PhotoImage(file=image_file_path,
                                   format="gif -index {}".format(frame_num))
            except TclError:
                break
            self._frames.append(frame)
            frame_num += 1

    def __len__(self):
        return len(self._frames)

    def __getitem__(self, frame_num):
        return self._frames[frame_num]


def update_label_image(label, ani_img, ms_delay, frame_num):
    global cancel_id
    label.configure(image=ani_img[frame_num])
    frame_num = (frame_num+1) % len(ani_img)
    cancel_id = root.after(
        ms_delay, update_label_image, label, ani_img, ms_delay, frame_num)

def enable_animation():
    global cancel_id
    if cancel_id is None:  # Animation not started?
        ms_delay = 1000 // len(ani_img)  # Show all frames in 1000 ms.
        cancel_id = root.after(
            ms_delay, update_label_image, animation, ani_img, ms_delay, 0)

def cancel_animation():
    global cancel_id
    if cancel_id is not None:  # Animation started?
        root.after_cancel(cancel_id)
        cancel_id = None


root = Tk()
root.title("Animation Demo")
root.geometry("250x125+100+100")
ani_img = AnimatedGif("small_globe.gif")
cancel_id = None

animation = Label(image=ani_img[0])  # Display first frame initially.
animation.pack()
Button(root, text="start animation", command=enable_animation).pack()
Button(root, text="stop animation", command=cancel_animation).pack()
Button(root, text="exit", command=root.quit).pack()

root.mainloop()