用Python写一个Tkinter拖动控件改变控件的大小的demo

好的，这是一个关于Tkinter拖动控件改变大小的Python代码示例：

import tkinter as tk

class ResizeableCanvas(tk.Canvas):
    def __init__(self, parent, **kwargs):
        tk.Canvas.__init__(self, parent, **kwargs)
        self.bind("<Configure>", self.on_configure)
        self.bind("<ButtonPress-1>", self.on_button_press)
        self.bind("<B1-Motion>", self.on_button_move)

        self.x_size = self.winfo_width()
        self.y_size = self.winfo_height()

    def on_configure(self, event):
        self.x_size = event.width
        self.y_size = event.height

    def on_button_press(self, event):
        self.startx = event.x
        self.starty = event.y

    def on_button_move(self, event):
        self.newx = event.x
        self.newy = event.y

        diffx = self.newx - self.startx
        diffy = self.newy - self.starty

        self.config(width=self.x_size + diffx, height=self.y_size + diffy)

if __name__ == '__main__':
    root = tk.Tk()
    canvas = ResizeableCanvas(root, bg="white", highlightthickness=0)
    canvas.pack(fill="both", expand=True)

    rectangle = canvas.create_rectangle(50, 50, 250, 250, fill="blue")

    root.mainloop()

以上代码可以创建一个可调整大小的画布（ResizeableCanvas），然后在该画布上绘制一个蓝色矩形。您可以尝试运行代码，并用鼠标拖动画布的边缘来调整画布的大小。