ShowWaveForm'�A C# Implementation of CWaveForm

Environment: VS.NET

Introduction

ShowWaveForm is based from a C++ class, called CWaveFile, written by Alexander Beletsky. 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 and 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 )
  {
    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 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 everything in this code! Specifically, I have questions about the following:

  • Drawing the 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

Downloads

Download demo project - 11 Kb
Download source - 2 Kb


Comments

  • Works on Linux too :)

    Posted by t3rmin4t0r on 06/09/2004 08:52am

    It works - though I think the color handling was ugly (read that as I hate white bgs :) http://demo.dotgnu.org/~t3rmin4t0r/waveform.png No changes except color .. if you look at the terminal , you'll see the compile command too. Anyway nice portable code :)

    Reply
  • Because it's your first attempt, it's very good.

    Posted by Wosiu on 04/13/2004 01:26pm

    Otherwise it would be Average. Thank you very much this is exactly what I was looking for. I'm currently analyzing your code to write something more advanced as my university project ;) thx

    Reply
Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • On-demand Event Event Date: September 10, 2014 Modern mobile applications connect systems-of-engagement (mobile apps) with systems-of-record (traditional IT) to deliver new and innovative business value. But the lifecycle for development of mobile apps is also new and different. Emerging trends in mobile development call for faster delivery of incremental features, coupled with feedback from the users of the app "in the wild." This loop of continuous delivery and continuous feedback is how the best mobile …

  • Packaged application development teams frequently operate with limited testing environments due to time and labor constraints. By virtualizing the entire application stack, packaged application development teams can deliver business results faster, at higher quality, and with lower risk.

Most Popular Programming Stories

More for Developers

Latest Developer Headlines

RSS Feeds