如何修复Tkinter中的滑块

Question

我一直在尝试为椭圆制作一个左、右和缩放滑块，但我无法使它们同步工作。它们自己工作，但当我试图在混合中添加第二个滑块时，它们只会重置位置和比例。我用repl.it编写代码。

这是我的代码：

import tkinter 
root = tkinter.Tk()
root.option_add('*Font', 'Times')
#####   MODEL  ######   
y_intvar = tkinter.IntVar()   #create special tk variable
y_intvar.set(150)             #set initial value
x_intvar = tkinter.IntVar()   
x_intvar.set(150)   
radius_intvar = tkinter.IntVar()
radius_intvar.set(150)          
r = 150                       #fixed value for radius
x = 150                       #fixed value for the x position
######   CONTROLLER   #########
# Event handler for slider
def y_changed(new_intval):
#read the value of y slider
y = y_intvar.get()
# update the view
canvas.coords(circle_item, x-r, y-r, x+r, y+r)

def x_changed(new_intval):
#read the value of y slider
x = x_intvar.get()
# update the view
canvas.coords(circle_item, x-r, y-r, x+r, y+r)
def radius_changed(new_intval):
# Get data from model
# Could do this: r = int(new_intval)
r = radius_intvar.get()
# Controller updating the view
canvas.coords(circle_item, x-r, y-r, x+r, y+r)
#create the slider
Y_slider = tkinter.Scale(root, from_=1, to=300, variable=y_intvar, label='y coordinate', command=y_changed, background='#FF6666')
X_slider = tkinter.Scale(root, from_=1, to=300, variable=x_intvar, label='x coordinate', command=x_changed, background='#FFFF33')
radius_slider = tkinter.Scale(root, from_=1, to=300, variable=radius_intvar,label='Radius         ', command=radius_changed, background='#66FF66')
#place the slider in row1 and column0
Y_slider.grid(row=2, column=0, sticky=tkinter.W)
X_slider.grid(row=3, column=0, sticky=tkinter.W)
radius_slider.grid(row=1, column=0, sticky=tkinter.W)
#directions for the user
text = tkinter.Label(root, text='Drag slider n to adjust n circle.')
text.grid(row=0, column=0)
######   VIEW   ################### present the information to user
#need a canvas to draw the circle on
canvas = tkinter.Canvas(root, width=500, height=500, background='#FFFFFF')
canvas.grid(row=0, rowspan=9, column=1)
# Create a circle on the canvas 
y = y_intvar.get()
x = x_intvar.get()
r = radius_intvar.get()
circle_item = canvas.create_oval(x-r, y-r, x+r, y+r,outline='#000000', fill='#00FFFF')
root.mainloop()```

Answer 1

您未在x_changed()、y_changed()和radius_changed():中将x、y和r声明为全局

def x_changed(new_intval):
global x
...
def y_changed(new_intval):
global y
...
def radius_changed(new_intval):
global r
...

---

实际上，您可以将这三个函数组合为一个，而不需要将这三种变量声明为全局：

def on_changed(_):
x = x_intvar.get()
y = y_intvar.get()
r = radius_intvar.get()
canvas.coords(circle_item, x-r, y-r, x+r, y+r)
#create the slider
Y_slider = tkinter.Scale(root, from_=1, to=300, variable=y_intvar, label='y coordinate', command=on_changed, background='#FF6666')
X_slider = tkinter.Scale(root, from_=1, to=300, variable=x_intvar, label='x coordinate', command=on_changed, background='#FFFF33')
radius_slider = tkinter.Scale(root, from_=1, to=300, variable=radius_intvar,label='Radius         ', command=on_changed, background='#66FF66')