GTune is a chromatic instrument tuner which operates much like its hardware counterparts. It will automatically detect the pitch of a note being played, and display the Western scale note that it is closest to.
The main part of the display mimics a typical electronic tuner. When a pitch is detected, the nearest note is displayed along with an LED-style indication of flatness/sharpness.
There is also a text display providing more accuracy, should it be needed. It gives the detected frequency in Hertz and its position in the Western scale. The latter is shown as a note-name and an offset in cents. For example, "E -13" indicates that the detected pitch is 13 cents below E.