A Slider Widget.
The Slider is the classic widget for controlling a bounded value.
A Slider Widget displays a range of values from which a user selects a single value between a minimum and a maximum value.
Slider widgets are usually created to control discrete integer values such as the number of coils of a coil spring .
The maximum/right most value.
The minimum/left most value.
Returns and sets if command will be called.
If True the command will be called while the slider is dragged, otherwise, it will only be called when the slider is released.