Tk window and contents will not display

Chris Hare chare at labr.net
Sun Aug 15 00:00:12 CEST 2010


On Aug 14, 2010, at 3:14 PM, Peter Otten wrote:

> Chris Hare wrote:
> 
>> The scenario is this:
>> 
>> I want to loop around all of the images in a given directory (which I know
>> will be images, but I guess I should check), show an image in a window,
>> wait 2 seconds and show the next one and repeat that indefinitley, which
>> will be until the user closes the window.
>> 
>> This is the code I extracted from the larger program and made work - sort
>> of - in a standalone fashion.  When I run the code, each of the file names
>> gets displayed, and I can view the images, so it has to be something I am
>> doing wrong with this chunk of code.
>> 
>> However, I don't see what the problem is.
> 
> I have not looked at your code in detail, but event loops and time.sleep() 
> don't play together very well. Use after(delay_in_milliseconds, callable) 
> instead. 
> 
> Here's a simple example that loops over images passed from the command line:
> 
> import Image
> import ImageTk
> import os
> import sys
> import Tkinter as tk
> 
> from itertools import cycle
> 
> def next_image():
>    imagefile = next(imagefiles)
>    image = Image.open(imagefile)
> 
>    w, h = image.size
>    image = image.resize((700, 700*h//w))
> 
>    label.image = label["image"] = ImageTk.PhotoImage(image=image)
>    root.title("Now showing %s" % os.path.basename(imagefile))
> 
>    root.after(2000, next_image)
> 
> if __name__ == "__main__":
>    imagefiles = sys.argv[1:]
>    assert imagefiles
>    imagefiles = cycle(imagefiles)
> 
>    root = tk.Tk()
>    label = tk.Label(root)
>    label.pack()
> 
>    root.after_idle(next_image)
>    root.mainloop()
> 

Thanks Peter.  I threw away what I started with and merged your code into my class:

class externalLoopDisplay:
    
    def show(self):        
        main.logging.debug("externalLoopDisplay.show:","start")

        self.window = Tk()

        self.btnClose = Button(self.window, text="Close", command=self.window.destroy, bg=backColor,highlightbackground=warnColor, highlightcolor=okColor)
        self.btnClose.grid(row=0, column=2)
        self.label = Label(self.window)
        self.label.grid(row=1, column=0, columnspan=3)
        dirName =  getRadarPath() + "/net" + str(netNumber.get()) # e.g. .../Radar/net17/net17-YYYYMMDDHHMMSS.gif
	self.imagefiles = glob.glob(dirName + "/*.gif")
	self.imagefiles = cycle(self.imagefiles)
        self.window.after_idle(self.next_image)

    def next_image(self):
        imagefile = next(self.imagefiles)
        image = Image.open(imagefile)
    
        w, h = image.size
        image = image.resize((600, 550*h//w))
    
        self.label.image = self.label["image"] = ImageTk.PhotoImage(image=image) # <==== bails here
        self.window.title("Now showing %s" % os.path.basename(imagefile))
    
        self.window.after(2000, next_image)


I marked where the code bails with an error saying pyimage2 doesn't exist.  All of the images exist and worked just fine with your standalone script.

Suggestions?




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