sizeDurationFactor property

double sizeDurationFactor
final

Controls how much longer the size animation is, relative to the fade, as a function of the size ratio between the two children. Must be >= 1.

Let P be the proportional area difference (larger area over smaller area, so P ≥ 1). The size animation runs for fadeDuration * P ^ (1 / sizeDurationFactor).

Intuition:

  • sizeDurationFactor = 1 — size scales linearly with P (bigger size change → proportionally longer size animation).
  • Larger values dampen the effect of P, pulling the size duration closer to fadeDuration.

Because R = P ^ (1 / sizeDurationFactor) is always >= 1, the size animation is never shorter than the fade.

Implementation

final double sizeDurationFactor;