Swing Hacks

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Chapter 10, Audio

#75 Build an Audio Waveform Display

HACK

Create a Container

Now that you have the waveform painting under control, you need to cre-

ate a container called

WaveformPanelContainer for SingleWaveformPanels in

order to show multi-channel audio. Figure 10-6 shows the waveform in the

simulator.

Example 10-7 is the complete code for the

WaveformPanelContainer.

AudioInfo is a helper class that contains references to the loaded audio sam-

ples and the current channel.

Figure 10-6. Multi-channel (stereo) audio in the simulator for this hack

Example 10-7. Testing out the waveform display

public class WaveformPanelContainer extends JPanel {

private ArrayList singleChannelWaveformPanels = new ArrayList( );

private AudioInfo audioInfo = null;

public WaveformPanelContainer( ) {

setLayout(new GridLayout(0,1));

}

public void setAudioToDisplay(AudioInputStream audioInputStream){

singleChannelWaveformPanels = new ArrayList( );

audioInfo = new AudioInfo(audioInputStream);

for (int t=0; t<audioInfo.getNumberOfChannels( ); t++){

SingleWaveformPanel waveformPanel

= new SingleWaveformPanel(audioInfo, t);

singleChannelWaveformPanels.add(waveformPanel);

add(createChannelDisplay(waveformPanel, t));

}

}