GrabAPI Namespace

This enum indicates whether a finger within a given GrabbingRule is required, optional, or ignored when determining if the rule is satisfied.

Optional finger requirements allow for a grab to be started and continued with different fingers. Consider, for example, a GrabbingRule in which all four fingers are optional and the thumb is ignored. With this grab, it is possible to begin a grab using only the first two fingers, then close the remaining fingers into the grab, then release the first two fingers out of the grab while still keeping the others curled. This will all be considered one grab action, even though no single finger was grabbing throughout; the grab was allowed to start without the last two fingers because those two fingers are optional, and it was allowed to persist when the first two fingers released because those are also optional.

This enum indicates whether a grab defined by a GrabbingRule ceases when any of its required fingers release, or when all of them release.

Fingers marked FingerRequirement.Optional or FingerRequirement.Ignored are not affected by this setting.