如何在python脚本中运行一个类

Question

我有一个名为 crop.py 的 python 脚本，当我通过 visual studio code 运行它时，它不会报告错误，但什么也没有发生，就像脚本期望其他命令起作用一样。 该代码允许您选择一个图像，根据四个点裁剪它，然后保存它。 这里的代码：

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

    class App:
        def __init__(self, root):
            self.root = root
            self.image = None
            self.image_tk = None
            self.points = []
            
            # create a canvas for the image
            self.canvas = tk.Canvas(root, width=600, height=600)
            self.canvas.pack()
    
            # bind the left mouse button click to the canvas
            self.canvas.bind("<Button-1>", self.select_point)
    
            # create a button to open an image file
            self.open_button = tk.Button(root, text="Open Image", command=self.open_image)
            self.open_button.pack()
    
            # create a button to crop the image
            self.crop_button = tk.Button(root, text="Crop Image", command=self.crop_image)
            self.crop_button.pack()
    
        def select_point(self, event):
            # add the selected point to the list
            self.points.append((event.x, event.y))
    
            # draw a circle at the selected point
            self.canvas.create_oval(event.x - 5, event.y - 5, event.x + 5, event.y + 5, fill="red")
    
            # if we have selected four points, unbind the left mouse button
            if len(self.points) == 4:
                self.canvas.unbind("<Button-1>")
    
        def open_image(self):
            # open a file dialog to select an image file
            file_path = filedialog.askopenfilename()
    
            # open the image file
            self.image = Image.open(file_path)
            
            # resize the image to fit the canvas
            self.image = self.image.resize((600, 600))
            
            # convert the image to a PhotoImage object
            self.image_tk = ImageTk.PhotoImage(self.image)
    
            # draw the image on the canvas
            self.canvas.create_image(0, 0, anchor="nw", image=self.image_tk)
    
        def crop_image(self):
            # check if we have selected four points
            if len(self.points) != 4:
                return
    
            # get the top-left and bottom-right points
            x1, y1 = self.points[0]
            x2, y2 = self.points[1]
            x3, y3 = self.points[2]
            x4, y4 = self.points[3]
    
            # find the top-left and bottom-right coordinates of the cropped image
            left = min(x1, x2, x3, x4)
            top = min(y1, y2, y3, y4)
            right = max(x1, x2, x3, x4)
            bottom = max(y1, y2, y3, y4)
    
            # crop the image
            cropped_image= image.crop((left,top,right,bottom))
    
            #save the cropped image
            cropped_image.save(filedialog.asksaveasfilename())

我没有使用 python 太久了，如果问题很简单，我很抱歉。 有人可以告诉我如何运行代码吗？ （打开图像，裁剪等。）

Answer 1

像那样实例化它并交出图像文件的名称。

app = App("filename of the image")