displaying an image full screen in Python - python-3.x

Question

The following program works the for the first .jpg in the directory.
When called the second time it gets a "_tkinter.TclError: image
"pyimage2" doesn't exist" exception. Why does it get the error? Is
there a way to reuse the first image rather than creating a second?
import sys, os
if sys.version_info[0] == 2:
import Tkinter
tkinter = Tkinter
else:
import tkinter
from PIL import Image, ImageTk
def showPIL(pilImage):
root = tkinter.Tk()
w, h = root.winfo_screenwidth(), root.winfo_screenheight()
root.overrideredirect(1)
root.geometry("%dx%d+0+0" % (w, h))
root.focus_set()
root.bind("<Escape>", lambda e: (e.widget.withdraw(), e.widget.quit()))
canvas = tkinter.Canvas(root,width=w,height=h)
canvas.pack()
canvas.configure(background='black')
imgWidth, imgHeight = pilImage.size
# resize photo to full screen
ratio = min(w/imgWidth, h/imgHeight)
imgWidth = int(imgWidth*ratio)
imgHeight = int(imgHeight*ratio)
pilImage = pilImage.resize((imgWidth,imgHeight), Image.ANTIALIAS)
image = ImageTk.PhotoImage(pilImage)
print(image)
imagesprite = canvas.create_image(w/2,h/2,image=image)
root.mainloop()
names = os.listdir("E://Users//scott//Pictures")
print(names)
for file in names:
print(file)
if file[-4:] == ".jpg":
file=Image.open("E://Users//scott//Pictures//"+file)
showPIL(file)
Here is the console output. Traceback (most recent call last): File
"e:\Users\scott\Documents\Python\image test.py", line 36, in
showPIL(file) File "e:\Users\scott\Documents\Python\image test.py", line 27, in showPIL
imagesprite = canvas.create_image(w/2,h/2,image=image) File "C:\Program Files\Python37\lib\tkinter__init__.py", line 2486, in
create_image
return self._create('image', args, kw) File "C:\Program Files\Python37\lib\tkinter__init__.py", line 2477, in _create
*(args + self._options(cnf, kw))))
_tkinter.TclError: image "pyimage2" doesn't exist
>

Answer 1

after searching around I discovered that the first problem that tkinter.Tk() was being called multiple times whereas it must be called
only once so I moved it out of the showPIL function and into the
initialization. The next problem is that mainloop blocks so I
replaced it with the combination of root.update_idletasks() and
root.update(). The following works as I expect and need:
import sys, os
if sys.version_info[0] == 2: # the tkinter library changed it's name from Python 2 to 3.
import Tkinter
tkinter = Tkinter #I decided to use a library reference to avoid potential naming conflicts with people's programs.
else:
import tkinter
from PIL import Image, ImageTk
import time
root = tkinter.Tk()
w, h = root.winfo_screenwidth(), root.winfo_screenheight()
root.overrideredirect(1)
root.geometry("%dx%d+0+0" % (w, h))
root.focus_set()
canvas = tkinter.Canvas(root,width=w,height=h)
canvas.pack()
canvas.configure(background='black')
def showPIL(pilImage):
imgWidth, imgHeight = pilImage.size
# resize photo to full screen
ratio = min(w/imgWidth, h/imgHeight)
imgWidth = int(imgWidth*ratio)
imgHeight = int(imgHeight*ratio)
pilImage = pilImage.resize((imgWidth,imgHeight), Image.ANTIALIAS)
image = ImageTk.PhotoImage(pilImage)
imagesprite = canvas.create_image(w/2,h/2,image=image)
root.update_idletasks()
root.update()
# root.bind("<Escape>", lambda e: (e.widget.withdraw(), e.widget.quit()))
names = os.listdir("E://Users//scott//Pictures")
print(names)
for file in names:
print(file)
if file[-4:] == ".jpg":
file=Image.open("E://Users//scott//Pictures//"+file)
showPIL(file)
time.sleep(5)