How to make random tests with tkinter (part 1)

This is the first part to make a test with tkinter. This will let you do different tests with random values easily.

from PIL import Image, ImageFont, ImageDraw
import os

class App:
    def __init__(self, title="Title", subtitle="A subtitle", image="logo.png", bg="coral"):
        self.title = title
        self.subtitle = subtitle
        self.bg = bg
        self.image = image
        self.size = 600, 400
        self.background = self.bg
        self.img = image
        self.shrink_ratio = 2 # use this in case you need to resize the image in the middle
        self.font = "arial", 38

        # do not need to customize this
        self.filename = "output\\" + self.img[:-4] + "_cover.png" # do not need to change this
        self.fnt = ImageFont.truetype(self.font[0], self.font[1])
        self.fnt2 = ImageFont.truetype("arial", 28)
        self.imgb = Image.new("RGB", (self.size), color=self.background)
        self.create_image()
        
    def create_image(self):
        self.img_middle = self.shrink(self.img, self.shrink_ratio)
        self.draw = ImageDraw.Draw(self.imgb)
        self.subtitle = self.subtitle
        self.draw.text((48, 30), self.title, font=self.fnt)
        self.draw.text((50, 80), self.subtitle, font=self.fnt2)
        self.half4 = (self.middle(self.img_middle,2))
        self.imgb.paste(self.img_middle, self.half4, self.img_middle)
        self.imgb.save(self.filename)
        self.imgb.show()
            
    def shrink(self, link, ratio=2):
        img = Image.open(link)
        w,h = img.size
        w = w // ratio # 2 is 50%
        h = h // ratio
        img = img.resize((w,h), Image.ANTIALIAS)
        return img

    def middle(self, img, m=2):
        return self.size[0] // m -img.size[0] // m, self.size[1] // 2 - img.size[1] // 4

ni = App(title = "How to create a GUI for tests",
         subtitle = "(random tests easily)",
         image = "logo.png",
         bg = "coral")