ScaleEndDetailsCancel extension

Partially cancel translation velocity based on scale velocity. Call at the start of onScaleEnd and use the returned details as the gesture's velocity for the rest of the release pipeline.

Two-stage cancellation: below a small threshold, no cancellation at all (the pinch was too subtle to count). Past the threshold, a baseline 30% cancellation kicks in, plus a quadratic growth term in the excess scale velocity. k ∈ [0, 1] scales the whole effect, so k=0 disables.

amount = k × (0.3 + (|scaleVelocity| − threshold)²) if past threshold factor = clamp(1 − amount, 0, 1)

  • k = 0 → never cancel.
  • k = 0.5, threshold = 0.1: scaleVel 0.1 → 15%; 0.5 → 23%; 1.0 → 55%.
  • k = 0.8, threshold = 0.1: scaleVel 0.1 → 24%; 0.5 → 37%; 1.0 → 89%.
  • k = 1.0, threshold = 0.1: scaleVel 0.1 → 30%; 0.5 → 46%; 1.0 → full.
on

Methods

cancelTranslation(double k) → ScaleEndDetails

Available on ScaleEndDetails, provided by the ScaleEndDetailsCancel extension

Constants

cancelTranslationBaseline → const double
Cancellation amount applied the moment |scaleVelocity| crosses cancelTranslationThreshold (before the quadratic growth term), scaled by k.
cancelTranslationThreshold → const double
|scaleVelocity| below this is treated as no-pinch — no cancellation.