Canvas.create_image()，可拖動影像似乎沒有從它的位置移動？

我目前正在使用 Tkinter，并且正在嘗試制作可拖動的畫布影像，這是我從另一個堆疊溢位問題“制作”/編輯的代碼，第二個是特別的。當我使用時，代碼對我有用tk.Frame()，但它給出了一個錯誤Canvas.create_image()。所以我對其進行了一些編輯，但現在當我拖動它時它似乎完全在移動影像

我的代碼：

from tkinter import *
import pyautogui

x,y=pyautogui.size()
tk = Tk()

c = Canvas(tk, width=x, height=y)
c.place(x=-2,y=-3)
img = ImageTk.PhotoImage(PIL.Image.open(r"Data\backgrounds\background.jpg"))
c.create_image(0, 0, image=img, anchor=NW)

def command6():
  print("command6")
  
def make_draggable(widget,btn="<Button-1>",motion="<B1-Motion>"):
    def __draggable__(widget):
        c.tag_bind(btn,btn,on_drag_start)
        c.tag_bind(motion,motion,on_drag_motion)
    
    def on_drag_start(event):
        widget = event.widget
        widget._drag_start_x = event.x
        widget._drag_start_y = event.y
    
    def on_drag_motion(event):   
        widget = event.widget
        x = widget.winfo_x() - widget._drag_start_x   event.x
        y = widget.winfo_y() - widget._drag_start_y   event.y
        widget.move(widget,x, y)

    __draggable__(widget)

APP_6 = r'apps\File.png'
APP_6 = PIL.Image.open(APP_6)
APP_6 = APP_6.resize((48,48),PIL.Image.ANTIALIAS)
APP_6 = ImageTk.PhotoImage(APP_6)

image_6 = ImageTk.PhotoImage(PIL.Image.open(r"apps\File.png"))
image_id_6 = c.create_image(48,48, image=APP_6)
c.move(image_id_6, 1,y-735)

c.tag_bind(image_id_6, '<Button-1>',command6)
make_draggable(image_id_6)    


tk.mainloop()

這不會在控制臺中產生任何錯誤或任何不需要的輸出。

uj5u.com熱心網友回復：

函式內部有幾個問題make_draggable()：

• 第一個引數.tag_bind()是畫布專案的專案 ID。對于您的情況，它widget是make_draggable(). 所以以下幾行：

        c.tag_bind(btn,btn,on_drag_start)
        c.tag_bind(motion,motion,on_drag_motion)

應該改為

        c.tag_bind(widget, btn, on_drag_start)
        c.tag_bind(widget, motion, on_drag_motion)

同樣適用于c.move(...)內部on_drag_motion()

• 移影片布專案的邏輯/計算錯誤

下面是修改后的make_draggable()函式：

def make_draggable(widget, btn="<Button-1>", motion="<B1-Motion>"):
    def __draggable__(widget):
        c.tag_bind(widget, btn, on_drag_start)
        c.tag_bind(widget, motion, on_drag_motion)
        c._item_id = widget # save the item ID for later use

    def on_drag_start(event):
        widget = event.widget
        # get the top-left coordinates of the selected item
        x, y, *_ = widget.bbox(widget._item_id)
        # save the offset of current mouse position from the top-left coordinates
        widget._dx = event.x - x
        widget._dy = event.y - y

    def on_drag_motion(event):
        widget = event.widget
        # calculate the top-left coordinates of the item that the item to be moved to
        x = event.x - widget._dx
        y = event.y - widget._dy
        # move the item using moveto() instead of move()
        widget.moveto(widget._item_id, x, y)

    __draggable__(widget)

由于上述邏輯僅適用于最后一次呼叫的專案make_draggable()。最好使用類而不是函式：

class make_draggable():
    def __init__(self, item_id, btn="<Button-1>", motion="<B1-Motion>"):
        self.item_id = item_id
        c.tag_bind(item_id, btn, self.on_drag_start, add=True)
        c.tag_bind(item_id, motion, self.on_drag_motion, add=True)

    def on_drag_start(self, event):
        x, y, *_ = event.widget.bbox(self.item_id)
        self.dx, self.dy = event.x-x, event.y-y

    def on_drag_motion(self, event):
        event.widget.moveto(self.item_id, event.x-self.dx, event.y-self.dy)

標籤：Python tkinter 可拖动的

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