Automatic Range

Two aids in the script help in automating any range changes. In the first an inline if clause is used where the numpy arange function, either adds 1 to the to_val (to) or if the tick_val (tickinterval) is less than 1 then adds tick_val to the to_val:

data = np.arange(from_val, (to_val+1 if tick_val >=1 else to_val+tick_val), tick_val)

The second is more complicated, in most ranges both the from and to range values are shown, but in the case of 0 to 255, as used in RGB displays, the highest value to is not usually displayed, as the Scale becomes too long if tick intervals are smaller than 10 or 20. The slider's maximum position will be at the to value, with its actual display value. On the other hand the highest range value shown will be the second to last in our range of values and its x position will be correspondingly less than the slider's maximum position.

In all cases the from value (x_min) is shown, so no change is required here, only the x_max or the position of the last displayed tick has to change:

if range_vals[-1] == to_val:
    pass
else:
    max_rv = range_vals[-1]
    mult_x = ((max_rv-from_val)*x_max/(to_val-from_val))

The actual value position uses the relative x computation uses an actual x placement, which helps in calibration:

x=(x_min + i / (len_rvs - 1) *
    ((x_max if range_vals[-1] == to_val else mult_x) - x_min)),

Both these changes are already in the calibration script.