Intonia is a Pitch Recorder. It's software intended to help String players visualize intonation. It combines the capabilities of an electronic tuner and a tape recorder. It keeps a memory of what it has heard, and displays pitch on a scrolling graph. You can specify what temperament to use: Equal, Just, or Pythagorean.
While it is recording, the display scrolls continuously. Your pitch is displayed as the height of the trace. If you're playing in tune the trace is white, but if you're sharp relative to your chosen scale and temperament, the trace is colored red. If you're flat, the trace is blue.
Originally intended simply to show intonation, it turns out to have many other uses:
Play a fast passage, and see which notes were out of tune.
See intonation in just, Pythagorean, or equal temperament.
Tune your instrument.
Use as a tape recorder to hear yourself play.
Edit your recording using cut and paste.
Get instant feedback.
Visualize articulations, slides, shifts, vibrato, etc.
Analyze historic recordings and other pre-recorded material.
Use it for transcription.
Works for all string instruments: cello through violin.
Works for many other instruments as well.