question: private void drawFrequencyLineAndLabel ( Graphics2D graphics , long frequency ) { double xAxis = getAxisFromFrequency ( frequency ) ; drawFrequencyLine ( graphics , xAxis , mColorSpectrumLine ) ; drawTickLine ( graphics , frequency , false ) ; graphics . setColor ( mColorSpectrumLine ) ; drawFrequencyLabel ( graphics , xAxis , frequency ) ; }
target:  Draws a vertical line and a corresponding frequency label at the bottom