cv2, tkinter, pillow - crop frame from camera

# author: Bartlomiej "furas" Burek (https://blog.furas.pl)
# date: 2020.07.06
# https://stackoverflow.com/questions/62746177/crop-webcam-live-with-cv2-in-python

import tkinter as tk
import cv2
from PIL import Image, ImageTk

# --- functions ---

def show_frame():

    ret, frame = cap.read()

    if frame is not None:

        # crop numpy array
        #frame = frame[0:900, 100:200]

        frame = cv2.flip(frame, 1)
        frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGBA)

        image = Image.fromarray(frame)

        # OR crop PIL image
        image = image.crop((100, 0, 200, 900))

        photo = ImageTk.PhotoImage(image=image)
        label_main.photo = photo
        label_main.configure(image=photo)

    label_main.after(10, show_frame)

# --- main ---

#width  = 1000
#height = 1000

cap = cv2.VideoCapture(0)
#cap.set(cv2.CAP_PROP_FRAME_WIDTH, width)
#cap.set(cv2.CAP_PROP_FRAME_HEIGHT, height)

root = tk.Tk()

#width_px  = root.winfo_screenwidth()
#height_px = root.winfo_screenheight()

#display = '{}x{}'.format(500, height_px)
#root.geometry(display)

#root.configure(background='green')

root.bind('<Escape>', lambda event:root.destroy())

label_main = tk.Label(root)
label_main.pack()

show_frame()

root.mainloop()

cap.release()