how to rendering the waveform

I do a project that need to transform the wave file (*.wav) to the waveform in the window (that is OSCILLOGRAM, the diagram that show the pressure change against time). How can i do that ? Do i need to know the wave file format first ? But i find many of the article about wave file format is teach we how to parse the chunk, but not parse the wave data in data chunk.
Thank for help ~