fresnelStrength property

double fresnelStrength
final

Scales the natural Fresnel edge luminosity on the Premium (Impeller) path.

The Premium shader always computes a physics-based Fresnel rim from the 3D surface normals of the glass bevel. This is the "lit physical glass" appearance. fresnelStrength multiplies the coefficient of that term:

  • 1.0 (default) — full Fresnel, matching iOS 26 glass buttons and panels that simulate real optical glass.
  • 0.0 — no Fresnel; the glass reads as a pure blur overlay with zero physics-based rim. Matches iOS 26 system UI glass such as Messages buttons, notification banners, and lock screen controls.
  • Intermediate values fade smoothly between the two appearances.

This has no effect on the Standard or Frosted rendering paths, which do not compute a 3D Fresnel term.

Defaults to 1.0.

Implementation

final double fresnelStrength;