Editor: gTuner has many features macintosh users and guitar players really need: first of all it helps you to tune your guitar - either in auto-mode, in which gTuner finds the matching string or in the manual-mode, where you can select the current string and tune guitars that are badly out of tune.
With Dock Tuning enabled, you can see if your guitar is tuned up even while you work with other applications. And this is possible because gTuner does not use much CPU power, too.
Autotuning
gTuner decides which string is used and computes the offset.
Manual Tuning
You decide which string you want to tune.
Dock Tuning
You can see whether you guitar is tuned up at any time.
Preferences
You can change the color of the needle, decide whether you would like to tune you guitar in an Open Tuning or change some advanced options.