如何使子Tkinter对象触发父窗口小部件中的更改

如何解决如何使子Tkinter对象触发父窗口小部件中的更改

编辑：由于下面@jasonharper的评论，我可以问一个更明智的问题：

我有一个主应用程序，还有一个单独的模块snipping_tool.py，该模块处理创建带有窗口截图或选择图像文件选项的新窗口。我希望snipping_tool.py向主应用提供图像，但是目前我试图检索图像太早（甚至在snipping_tool窗口打开之前）。

在尝试分配MyNewObject.selected_image之前，如何等待用户选择或抓取图像？我应该使用binding还是某些事件处理程序？（我对两者的经验都有限）。还是有更简单的方法？

简化的主应用程序：

import tkinter as tk
import snipping_tool

class MinCodeEx:
    def __init__(self,master):
        self.master = master
        self.ButtonA = tk.Button(width=60,height=40,command = lambda: self.UpdateImg(master))
        self.ButtonA.pack()
    def UpdateImg(self,master):
        newDialog = snipping_tool.AcquireImage(self.master)
        # self.ButtonA['image'] = newDialog.image_selected
        #if newDialog.image_selected:
        self.ButtonA.config(image=newDialog.image_selected)
        print(newDialog.image_selected)

def main():
    root = tk.Tk()
    MinCodeEx(root)
    root.mainloop()

if __name__ == '__main__':
    main()

snipping_tool.py

返回 None 而不是图像文件，因为我尝试过早检索selected_image。

import tkinter as tk
from PIL import ImageGrab,ImageTk,Image
import cv2
import numpy as np
from tkinter import filedialog


class ScreenSnip(tk.Toplevel):
    def __init__(self,master):
        super().__init__(master)
        self.image = None

    def get_snip(self):
        self.configure(cursor='cross')
        self.attributes('-fullscreen',True)
        self.attributes('-alpha',0.4)

        self.canvas = tk.Canvas(self,bg='dark gray')
        self.canvas.pack(fill='both',expand=True)

        self.begin_x = 0
        self.begin_y = 0
        self.end_x = 0
        self.end_y = 0
        self.click_drag = False

        self.canvas.create_rectangle(0,outline='#0052d6',width=2,fill='white',tags='snip_rect')
        self.canvas.bind('<ButtonPress-1>',self.mousePressEvent)
        self.canvas.bind('<B1-Motion>',self.mouseMoveEvent)
        self.canvas.bind('<ButtonRelease-1>',self.mouseReleaseEvent)

        print('Capture the screen...')

    def mousePressEvent(self,event):
        self.begin_x = event.x
        self.begin_y = event.y
        print(self.begin_x,self.begin_y)

    def mouseMoveEvent(self,event):
        self.click_drag = True
        self.end_x = event.x
        self.cur_y = event.y
        width = self.end_x - self.begin_x
        height = abs(width * 2/3)
        if self.cur_y < self.begin_y:
            height *= -1
        self.end_y = self.begin_y + height
        self.canvas.coords('snip_rect',self.begin_x,self.begin_y,self.end_x,self.end_y)

    def mouseReleaseEvent(self,event):
        self.destroy()
        self.master.update_idletasks()
        self.master.after(100)  # give time for screen to be refreshed so as not to see the blue box on the screenshot
        if not self.click_drag: # if the user just clicks,instead of clicking and dragging
            self.begin_x -= 300
            self.begin_y += 200
            self.end_x = self.begin_x + 600
            self.end_y = self.begin_y - 400
        x1 = min(self.begin_x,self.end_x)
        y1 = min(self.begin_y,self.end_y)
        x2 = max(self.begin_x,self.end_x)
        y2 = max(self.begin_y,self.end_y)

        self.img = ImageGrab.grab(bbox=(x1,y1,x2,y2))
        self.image = ImageTk.PhotoImage(self.img)
        #self.img = cv2.cvtColor(np.array(img),cv2.COLOR_BGR2RGB)
        #cv2.imshow('Captured Image',self.img)
        #cv2.waitKey(0)

font1 = ("arial",18,"bold")

class AcquireImage:
    def __init__(self,master):
        self.master = master
        self.nWin = tk.Toplevel(master)
        self.fontA = ("arial",20,"bold")

        self.frame = tk.Frame(self.nWin,bg="#1B2631")
        self.frame.pack(fill="both",expand=True)

        self.button1 = tk.Button(self.frame,text="Select Image File",padx=10,pady=10,bg="#d9a193",font = self.fontA,command =lambda: self.show_dialogs(1))
        self.button1.grid(row=0,column=0,sticky="nsew")#,pady=10)

        self.button2 = tk.Button(self.frame,text="Get Screen Snip",command=lambda: self.show_dialogs(2))
        self.button2.grid(row=0,column=1,pady=10)

        self.image_selected = None

    def show_dialogs(self,method): ###################  THIS IS WHERE THE IMAGE IS SELECTED ###########

        if method == 1:
            ret = filedialog.askopenfilename()
            if ret:
                self.image_selected = ImageTk.PhotoImage(file = ret)
                self.nWin.destroy()

        elif method == 2:
            newWin = ScreenSnip(self.nWin)
            newWin.get_snip()
            ret = newWin.image
            if ret:
                self.image_selected = ret


def main():
    root = tk.Tk()
    AcquireImage(root)
    root.mainloop()


if __name__ == '__main__':
    main()

解决方法

@jasonharper是正确的。此解决方案来自他的评论。

在创建AcquireImage的实例时，我还传递了ButtonA作为参数，以便可以修改其图像。在AcquireImage中，我首先获得一个新图像（通过剪裁或使用文件资源管理器），然后为避免垃圾回收立即删除它，我将其分配给ButtonA.img进行保存。（我首先在主程序中创建ButtonA的.img部分）。有了图片后，就可以分配它了。

我可能还可以通过创建一个函数来解决此问题在主程序中更改任何小部件的图像传递给它作为参数。然后，我可以将此功能传递给以AcquireImage为参数的ButtonA实例。它可能在主程序中看起来像这样：def callback(i_file): ButtonA['image'] = i_file newDialog = snipping_tool.AcquireImage(self.master,self.callback)后来我将用AcquireImage初始化/定义 self.some_function作为第二个参数（仅次于master），我可以将图像文件传递给它。至少那是我可能的方式已经做到了。

这是我实际解决的方式：

主要应用

import tkinter as tk
import snipping_tool
waitingforImage = True
class MinCodeEx:
    global waitingforImage
    def __init__(self,master):
        self.master = master
        self.ButtonA = tk.Button(width=60,height=40,command = lambda: self.UpdateImg())
        self.ButtonA.pack()
        self.ButtonA.img = None

    def UpdateImg(self):
        newDialog = snipping_tool.AcquireImage(self.master,self.ButtonA)

def main():
    root = tk.Tk()
    MinCodeEx(root)
    root.mainloop()

if __name__ == '__main__':
    main()

snipping_tool.py

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


class ScreenSnip(tk.Toplevel):
    def __init__(self,master,changeThis):
        super().__init__(master)
        self.image = None
        self.master = master
        self.changeThis = changeThis

    def get_snip(self):
        self.configure(cursor='cross')
        self.attributes('-fullscreen',True)
        self.attributes('-alpha',0.4)
        print("attempting to create tk.Canvas for get_snip")
        self.canvas = tk.Canvas(self,bg='dark gray')
        self.canvas.pack(fill='both',expand=True)

        self.begin_x = 0
        self.begin_y = 0
        self.end_x = 0
        self.end_y = 0
        self.click_drag = False

        self.canvas.create_rectangle(0,outline='#0052d6',width=2,fill='white',tags='snip_rect')
        self.canvas.bind('<ButtonPress-1>',self.mousePressEvent)
        self.canvas.bind('<B1-Motion>',self.mouseMoveEvent)
        self.canvas.bind('<ButtonRelease-1>',self.mouseReleaseEvent)

        print('Capture the screen...')

    def mousePressEvent(self,event):
        self.begin_x = event.x
        self.begin_y = event.y
        print(self.begin_x,self.begin_y)

    def mouseMoveEvent(self,event):
        self.click_drag = True
        self.end_x = event.x
        self.cur_y = event.y
        width = self.end_x - self.begin_x
        height = abs(width * 2/3)
        if self.cur_y < self.begin_y:
            height *= -1
        self.end_y = self.begin_y + height
        self.canvas.coords('snip_rect',self.begin_x,self.begin_y,self.end_x,self.end_y)

    def mouseReleaseEvent(self,event):
        self.destroy()
        self.master.update_idletasks()
        self.master.after(100)  # give time for screen to be refreshed so as not to see the blue box on the screenshot
        if not self.click_drag: # if the user just clicks,instead of clicking and dragging
            self.begin_x -= 300
            self.begin_y += 200
            self.end_x = self.begin_x + 600
            self.end_y = self.begin_y - 400
        x1 = min(self.begin_x,self.end_x)
        y1 = min(self.begin_y,self.end_y)
        x2 = max(self.begin_x,self.end_x)
        y2 = max(self.begin_y,self.end_y)

        self.img = ImageGrab.grab(bbox=(x1,y1,x2,y2))
        print("getting image grab")
        self.changeThis.img = ImageTk.PhotoImage(self.img)
        self.changeThis['image'] = self.changeThis.img

font1 = ("arial",18,"bold")

class AcquireImage:
    def __init__(self,changeThis):
        self.master = master
        self.changeThis = changeThis
        self.nWin = tk.Toplevel(master)
        self.fontA = ("arial",20,"bold")

        self.frame = tk.Frame(self.nWin,bg="#1B2631")
        self.frame.pack(fill="both",expand=True)

        self.button1 = tk.Button(self.frame,text="Select Image File",padx=10,pady=10,bg="#d9a193",font = self.fontA,command =lambda: self.show_dialogs(1))
        self.button1.grid(row=0,column=0,sticky="nsew")#,pady=10)

        self.button2 = tk.Button(self.frame,text="Get Screen Snip",command=lambda: self.show_dialogs(2))
        self.button2.grid(row=0,column=1,pady=10)

        self.image_selected = None

    def show_dialogs(self,method):
        if method == 1:
            ret = filedialog.askopenfilename() #filedialog.askopenfilename(initialdir='/home/user/images/')
            self.changeThis.img = ImageTk.PhotoImage(file = ret)
            self.changeThis['image'] = self.changeThis.img
        elif method == 2:
            print("attempting ScreenSnip")
            newWin = ScreenSnip(self.master,self.changeThis)
            newWin.get_snip()
        self.nWin.destroy()

def main():
    root = tk.Tk()
    bt = tk.Button(root,width = 20,height = 20)
    bt.pack()
    ScreenSnip(root,bt)
    #AcquireImage(root,bt)
    root.mainloop()


if __name__ == '__main__':
    main()

我仍然需要修复一个不相关的问题-该按钮不适合我选择或抓取的图像的大小。它总是最终变成一个小正方形。

如何使子Tkinter对象触发父窗口小部件中的更改

如何解决如何使子Tkinter对象触发父窗口小部件中的更改

解决方法

相关推荐