The change_value signal is emitted when a scroll action is performed on a range.
It allows an application to determine the type of scroll event that occurred and the resultant new value. The application can handle the event itself and return true to prevent further processing. Or, by returning false , it can pass the event to other handlers until the default GTK handler is reached.
The value parameter is unrounded. An application that overrides the GtkRange:
GtkRange:change-value signal is responsible for
clamping the value to the desired number of decimal digits; the default GTK handler clamps the value based on
the type of scroll action that was performed
the new value resulting from the scroll action
true to prevent other handlers from being invoked for the signal, false to propagate the signal further