private boolean isInThumbRange(float touchX,double normalizedThumbValue){
  return Math.abs(touchX - normalizedToScreen(normalizedThumbValue)) <= thumbHalfWidth;
}

private boolean isInThumbRange ( float touchX , double normalizedThumbValue ) { return Math . abs ( touchX - normalizedToScreen ( normalizedThumbValue ) ) <= thumbHalfWidth ; }
decides if given x - coordinate in screen space needs to be interpreted as " within " the normalized thumb x - coordinate .
