Calculate the Length#

length estimated by script

Script estimates size#

There is an alternative to adjusting the Scale length until after it is drawn then changing the window size. Estimate the required length, use the range values, measure each range value then allow for the empty space between ticks (width of a zero):

data = np.arange(from_val, to_val+tick_val, tick_val)
data = np.round(data,1)
range_vals = tuple(data)

vals_size = def_font.measure(str(i)) for i in range_vals]
data_size = sum(vals_size)

len_rvs = len(range_vals)
space_size = len_rvs * def_font.measure('0')

min_len = int(ceil((data_size+space_size) / 50.0)) * 50

This code needs to be positioned before the Scale length (len_val) is used for calculation.

Show/Hide Code 09ttk_tkinter_estimate_size.py

import tkinter as tk
from tkinter import font
import tkinter.ttk as ttk
import numpy as np

from_val = -1
to_val = 1
#len_val = 500
res_val = 0.1
tick_val = 0.1
dig_val = 2
bw_val = 1 # trough border width
slider_val = 36
sc_range = abs(to_val - from_val) # scale range

def place_ticks(evt):
    len_val = scth['length']
    rel_min = ((slider_val - from_size) / 2 + bw_val) / len_val
    rel_max = 1 - ((slider_val - to_size )/ 2 - bw_val) / len_val
    data = np.arange(from_val, to_val+tick_val, tick_val)
    data = np.round(data,1)
    range_vals = tuple(data)
    len_rvs = len(range_vals)

    for i, rv in enumerate(range_vals):
        rel_x=(rel_min + i / (len_rvs - 1) * (rel_max - rel_min))
        item.place_configure(relx=rel_x)

root = tk.Tk()

def_font = font.nametofont('TkDefaultFont')
# using numpy arange instead of range so tick intervals less than 1 can be used
data = np.arange(from_val, to_val+tick_val, tick_val)
data = np.round(data,1)
range_vals = tuple(data)

vals_size = [def_font.measure(str(i)) for i in range_vals]
data_size = sum(vals_size)
len_rvs = len(range_vals)
space_size = len_rvs * def_font.measure('0')
sizes = data_size + space_size
len_val = (sizes if sizes % 50 == 0 else sizes + 50 - sizes % 50)

root.geometry(str(len_val+200)+"x200+500+500")
s = ttk.Style()
s.theme_use('default')

fr = ttk.Frame(root)
fr.pack(fill='x', expand=1)

from_size = def_font.measure(from_val)
to_size = def_font.measure(to_val)

sch = tk.Scale(fr, from_=from_val, to=to_val, label='Bogusstuinuous', orient='horizontal',
            resolution=res_val, showvalue=1, tickinterval=tick_val, digits=dig_val,
            length=len_val)
sch.grid(sticky='ew')

sep = ttk.Separator(fr, orient='horizontal')
sep.grid(row=1, column=0, columnspan=2, sticky='ew')

def convert_to_relx(curr_val):
    return ((curr_val - from_val) * (rel_max - rel_min) / (to_val - from_val) \
            + rel_min)


def display_value(value):
    # position (in pixel) of the center of the slider
    rel_x = convert_to_relx(float(value))
    disp_lab.place_configure(relx=rel_x)
    disp_lab.configure(text=f'{float(value):.{dig_val}f}')

slider = tk.StringVar()
slider.set('0.00')

scth = ttk.Scale(fr, from_=from_val, to=to_val, length=len_val,
        command=display_value, variable=slider)

scth.grid(row=2, column=0, sticky='ew', padx=5, pady=15)

rel_min = ((slider_val - from_size) /2 + bw_val) / len_val
rel_max = 1 - ((slider_val + to_size) /2 + bw_val) / len_val

x_min = (slider_val - from_size) /2 + bw_val
x_max = len_val - (slider_val + to_size) /2 + bw_val

for i, rv in enumerate(range_vals):
    item = ttk.Label(fr, text=rv)
    item.place(in_=scth, bordermode='outside',
                relx=(rel_min + i / (len_rvs - 1) * (rel_max - rel_min)) ,
                rely=1, anchor='n')

disp_lab = ttk.Label(fr)
rel_x = convert_to_relx(float(scth.get()))
disp_lab.place(in_=scth, bordermode='outside',
                relx=rel_x, rely=0, anchor='s')
display_value(scth.get())

sbh = ttk.Spinbox(fr, from_=from_val, to=to_val, textvariable=slider,
                  width=5, increment=res_val)
sbh.grid(row=2, column=1, sticky='ew')

root.mainloop()

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