fresnel_android #

Android implementation of fresnel.

Apps depend on fresnel, which selects this package automatically on Android.

What it does #

Android has no Liquid Glass, and this package does not pretend otherwise. It has two jobs.

Report capabilities honestly. Without it the façade falls back to GlassCapabilities.unsupported(), which claims reduce-motion and increase-contrast are off rather than asking. Those flags are exactly the ones the shader path has to honour itself — on the native path the OS does it for us — so guessing them wrong is an accessibility failure, not a cosmetic one.

Hand widgets the right tokens. AndroidGlassTokens carries the Material 3 Expressive corner scale and motion scheme, so a surface that cannot be glass degrades to something that looks like Android instead of a flattened iOS control.

import 'package:fresnel_android/fresnel_android.dart';

GlassSurface(
  shape: AndroidGlassTokens.shapeExtraLarge,
  child: const Text('Hello'),
)

How the accessibility flags are read #

• reduceMotion — Settings.Global.TRANSITION_ANIMATION_SCALE == 0, with ANIMATOR_DURATION_SCALE as a second probe because some OEM skins zero only one of the two. Android has no isReduceMotionEnabled, and AccessibilityManager.isEnabled is not a stand-in: it is true whenever any accessibility service runs, TalkBack included, and TalkBack users have not asked for animations to stop.
• increaseContrast — UiModeManager.getContrast() > 0 on API 34+, the only public API for it. Below that, the secure high_text_contrast_enabled key (stable since API 21 but @hide) and colour inversion.
• reduceTransparency — always false. Android has no such preference, and deriving one from "Remove animations" would make every surface opaque for users who only asked for stillness.
• osMajorVersion — deliberately not sent. The contract documents it as null off Apple platforms, and an API level in a field callers read as an Apple major version is worse than no value.

No permissions are declared; every setting read here is world-readable.

Why the tokens are what they are #

Material 3 Expressive replaced the duration/easing motion tokens with a spring-based scheme in two families. Spatial springs move things and are underdamped on purpose, so they overshoot — that overshoot is the expressiveness. Effects springs change colour, opacity and elevation and are critically damped, because an overshooting colour reads as a flicker. AndroidGlassTokens exposes both, plus the emphasized duration/curve set for the parts of Flutter's animation API that still want a fixed time.

The shape defaults follow suit: defaultShape is the 16dp large corner, and shapeFull is a capsule with true circular arcs rather than a superellipse. The squircle is Apple's corner; using it here would be the exact mistake this package exists to avoid.

Layout #

lib/fresnel_android.dart              FresnelAndroid, the platform impl
lib/src/android_glass_tokens.dart     the M3 Expressive shape + motion tokens
android/build.gradle.kts
android/src/main/AndroidManifest.xml
android/src/main/kotlin/com/waqaralisiyal/fresnel_android/
  FresnelAndroidPlugin.kt             getCapabilities, and nothing else

License #

MIT. See LICENSE.