@func allows you to change how the scale value is displayed.
The given function will return an allocated string representing @value. That string will then be used to display the scale's value.
If #NULL is passed as @func, the value will be displayed on its own, rounded according to the value of the [property@GtkScale:digits] property.
function that formats the value
user data to pass to @func
destroy function for @user_data
See Implementation
@func allows you to change how the scale value is displayed.
The given function will return an allocated string representing @value. That string will then be used to display the scale's value.
If #NULL is passed as @func, the value will be displayed on its own, rounded according to the value of the [property@GtkScale:digits] property.