Perimeter

Strategy module: appdimens_perimeter · part of the AppDimens Flutter family

What it is

Scales by the ratio of the window half-perimeter to the baseline half-perimeter (833 dp).

Calculation used

$\text{text} \text{out} = \text{b} \times (\text{s\_min} + \text{s\_max}) / 833 $

Qualifier-independent; the default path reuses the memoized perimeterScale.

How to use

import 'package:appdimens_perimeter/appdimens_perimeter.dart';
final size = 16.prsdp;   // same value on every axis

Why use it

Averaging both sides makes the factor stable under rotation (portrait/landscape converge).

When to use it

Elements that should react to overall window growth but stay rotation-stable, like toolbars and bottom bars.

Advantages & trade-offs

✅ Advantages	⚠️ Trade-offs
Rotation-stable · single cheap factor
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Recommended usage strategy

Consider Perimeter as the orientation-agnostic sibling of Scaled.

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