Creates a new scale widget with the given orientation that lets the user input a number between @min and @max (including @min and @max) with the increment @step. @step must be nonzero; it's the distance the slider moves when using the arrow keys to adjust the scale value. Note that the way in which the precision is derived works best if @step is a power of ten. If the resulting precision is not suitable for your needs, use gtk_scale_set_digits() to correct it.