This demonstrates the addition of swing in a tune. The swing is added to the MIDI player, so it is not reflected in the sheet music. The swing is represented as a percentage of the duration of the first note to the duration of the pair of eighth notes. The default is 50%, which is no swing; both eights have the same duration and the ratio is 1:1. 66% is a common value for triplet-swing, with a 2:1 ratio of the first note to the second. Other common swing values are 60% which corresponds to a 3:2 ratio of the first note to the second and 57% which corresponds to a 4:3 ratio. The maximum value of swing is 75; in this case the first half of the pair is 3 times longer than the second half. resulting to a 3:1 ratio or a dotted-eighth followed by a sixteenth note.
In the example below, change the value of the swing to see how it matches of differs from the explicit triplets of dotted eighth and sixteenth notes.
Swing is supported in all X/4 and X/8 meters. In a X/8 meter the sixteenths swing. You can try a X/8 meter by changing the meter in the ABC string to "M: 4/8 L: 1/16" However, meter changes in the middle of a tune do not affect the main swing duration.