public void scrollByUnit(int direction) {
float size;
if (orientation == VERTICAL) {
direction *= -1;
size = scrollSpace + slider.getThumbButton().getHeight() / slider.getHeight();
} else size = scrollSpace + slider.getThumbButton().getWidth() / slider.getWidth();
if (direction == DECREMENT) setValue(getValue() - size);
else setValue(getValue() + size);
}