KeyCombination

A KeyCombination (AKA keyboard shortcut), is a combination of a Key, and set of zero or more modifier keys (Shift, Control, Alt and Super).

They are commonly used to define shortcuts for actions. For example, the standard Undo KeyCombination is Control + Key.Z.

Use KeyEvent.matches to test if a KeyEvent matches a particular KeyCombination.

There are methods on Key and KeyCombination to create KeyCombinations in a readable manner. e.g. :

val undoShortcut = Key.Z.control()
val redoShortcut = Key.Y.control()
val redoShortcut2 = Key.Z.control().shift()

In most cases the modifiers are boolean, but can also use a third don't care state.

For example, we could define Zoom In to be just key MINUS (with no modifiers). But if you do not care about the state of the Shift modifier, then use Key.maybeShift. Now, Zoom In would match MINUS as well as Shift + MINUS.

I chose this example, because of Zoom Out. There is no PLUS key! (PLUS is Shift + EQUALS).

val zoomOut = Key.MINUS.maybeShift() // Or we could use Key.MINUS.noMods()
val zoomIn = Key.EQUAL.maybeShift()

Pressing the Equals key will match zoomIn, regardless of whether Shift is down or up, but will not match if Control, Super or Alt are pressed.