[JUCE API] PingPong Delay(3)

3. The plugin editor should also detect the ping-pong button state.

AudioProcessorEditor  : private juce::Button::Listener
{
	public:
    	AudioProcessorEditor()
        :mButtonPingPong(mPanelControl.getButtonPingPong())
        {
            mButtonPingPong.addListener(this);
        }
    private:
        juce::Button& mButtonPingPong;
        void buttonClicked(juce::Button* inButton) override;
}

The pure virtual function buttonClicked() should display only half of the delay panel.

void buttonClicked(juce::Button* inButton)
{
    switch (inButton -> getCommandID())
    {
        case MyHelper::CmdIdButtons::PingPong:
        {
            mPanelDelay.setSize(MySize::Panel::Delay::Width,
                                inButton -> getToggleState() ?  MySize::Panel::Delay::Height / 2:
                                                                MySize::Panel::Delay::Height );
            mPanelDelay.repaint();
            break;
        }
        default: break;
    }
}

Using the component's pure virtual function resized(), redraw the delay panel at half-height whenever the ping-pong button is pressed.

4. Create a ping-pong panel and show it below the delay panel whenever the ping-pong button is pressed

EulerDelayAudioProcessorEditor():
{
  	mPanelPingPong.setVisible(mButtonPingPong.getToggleState());
}

In the constructor, detect the initial state when the plugin loads to decide whether to show the ping-pong panel.

void buttonClicked(juce::Button* inButton)
{
    switch (inButton -> getCommandID())
    {
        case MyHelper::CmdIdButtons::PingPong:
        {
    		mPanelPingPong.setVisible(mButtonPingPong.getToggleState());
            break;
        }
        default: break;
    }
}

Naturally, since the ping-pong panel should appear in the space freed by the delay panel when the button is pressed, this behavior is implemented in the buttonClicked() function.