Fluid

Strategy module: appdimens_fluid · part of the AppDimens Flutter family

What it is

CSS-clamp-like behavior: the value plateaus at b×0.8 on small screens, at b×1.2 on large ones, and interpolates linearly between 320 and 768 dp.

Calculation used

d ≤ 320 : b × 0.8
320 < d < 768 : lerp(b×0.8, b×1.2, (d − 320) / 448)
d ≥ 768 : b × 1.2

Plateaus guarantee hard bounds — typography never becomes unreadably small or comically large.

How to use

import 'package:appdimens_fluid/appdimens_fluid.dart';
final size = 16.fsdp;      // fluid on sw
final h    = 16.fhdp;
final w    = 16.fwdp;

Why use it

Designers specify a safe range once and the engine interpolates inside it; no manual breakpoints.

When to use it

Typography scales, paddings and component sizes with strict min/max requirements.

Advantages & trade-offs

✅ Advantages	⚠️ Trade-offs
Hard clamps · smooth in between · tiny constant-time formula
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Recommended usage strategy

The default range (±20% over [320, 768]) fits most typography; combine with a if the clamp should follow the aspect ratio too.

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AppDimens Flutter 3.2.0 — see MATHEMATICS-AND-CALCULUS.md for the formal derivation.