You can use constants of type ThemeThumbDirection in the SliderTrackInfo structure to identify the direction in which the indicator points in a slider control. You may use these constants with either horizontal or vertical sliders, and the Appearance Manager interprets the direction of the indicator appropriately. The ThemeThumbDirection constants are available with Appearance Manager 1.1 and later.
enum {
kThemeThumbPlain = 0,
kThemeThumbUpward = 1,
kThemeThumbDownward = 2
};
typedef UInt8 ThemeThumbDirection;