ShowWaveForm

• Download source files - 2 Kb
• Download demo project - 11 Kb

Introduction

ShowWaveForm is based off of a c++ class written by Alexander Beletsky called CWaveFile. This is a port to C#, with some added features. A small .wav file is included in the demo project .zip file for testing.

WaveFile.cs

WaveFile.cs is the main class. It reads & parses the .WAV file headers. When passed a PaintEventArgs (typically from an OnPaint event), it will draw the waveform. The class also allows for zooming in/out on the waveform.

Usage

Using the class is very simple. Here is the sample project file open menu handler:

private void fileOpen_Click(object sender, System.EventArgs e)
{
  OpenFileDialog fileDlg = new OpenFileDialog();

  if ( fileDlg.ShowDialog() == DialogResult.OK )
  {
     wave = new WaveFile( fileDlg.FileName );
     sbpMainPanel.Text = "Reading .WAV file...";
     wave.Read( );
     sbpMainPanel.Text = "Finished Reading .WAV file...";
     m_DrawWave = true;
     Refresh( );
  }
}

And here is the Paint handler of the demo project:

private void Form1_Paint( object sender, 
              System.Windows.Forms.PaintEventArgs e
            )
{
  Pen pen = new Pen( ForeColor );
  if ( m_DrawWave )<BR>  {
     sbpMainPanel.Text = "Drawing .WAV file...";
     wave.Draw( e, pen );
     sbpMainPanel.Text = "Finished drawing .WAV file...";
  }
}

The last interesting thing in the demo project is the MouseWheel handler, which controls the zooming of the waveform:

protected override void OnMouseWheel( MouseEventArgs mea )
{
 if ( mea.Delta * SystemInformation.MouseWheelScrollLines / 120 > 0 )
  wave.ZoomIn( );
 else
  wave.ZoomOut( );

 Refresh( );

}

Questions/Discussion

This is my first attempt at programming in C#/.NET. So please comment on every thing in this code! Specifically I have questions about:

• Drawing of waveform is very slow for large files, perhaps because of using PageScale?
• How to catch some of the errors that can occur in zooming in/out too far
• Drawing of stereo waveforms

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