In a Tkinter slider, can you vary the range from being linear to exponential for easier number selec-CodePudding

I'm currently creating a library for a blackjack simulator in Python. Connecting to the simulator is a Tkinter GUI which controls the input. I want the input to range from 1-50,000,000; however, I want users to be able to easily select smaller number ranges such as 15,000-75,000.

I figure the best way to do this would be by having the range of values in the slider update using f(x)=x^2 instead of it's normal linear behavior.

I believe I could create a new widget which displays the value of the f(x)=x^2 function where the input is slider.get() of the slider widget. But I was hoping someone knows of a more elegant solution that could display and use this f(x)=x^2 value using the slider widget itself.

Here's basic widget code ripped off of a tutorial's point example found here: https://www.tutorialspoint.com/python/tk_scale.htm


def sel():
   selection = "Value = "   str(var.get())
   label.config(text = selection)

root = Tk()
var = DoubleVar()
scale = Scale( root, variable = var )
scale.pack(anchor=CENTER)

button = Button(root, text="Get Scale Value", command=sel)
button.pack(anchor=CENTER)

label = Label(root)
label.pack()

root.mainloop()```

CodePudding user response：

You can create a version of the Scale widget that will return the value of the slider but with a specific mathematically function applied. In the example below I return x^2.

import tkinter as tk

def sel():
   selection = "Value = "   str(scale2.value)
   label.config(text = selection)

class LogScale(tk.Scale):
    def __init__(self,parent,**kwargs):
        tk.Scale.__init__(self,parent,**kwargs)
        self.var = tk.DoubleVar()
        #self.config[showvalue] = 0
        self['showvalue'] = 0
        self['label'] = 0
        self['command'] = self.update
        self['variable'] = self.var

    def update(self,event):
        self.config(label=self.value)

    @property
    def value(self):
        return str(int(self.var.get()) ** 2)

root = tk.Tk()

scale2 = LogScale(root)
scale2.pack()

button = tk.Button(root, text="Get Scale Value", command=sel)
button.pack(anchor=tk.CENTER)

label = tk.Label(root)
label.pack()

root.mainloop()

I've hidden the normal label that moves alongside the slider and have used the other label to display the "modified" value.