@programmer1zero1/expo-responsive-window

Window-aware breakpoints, scaled design pixels, and gutters for Expo / React Native. Live on rotation & resize. Includes README + AGENTS.md.

Unofficial package — not from the Expo team.

Demo

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Install

npm install @programmer1zero1/expo-responsive-window
# or
yarn add @programmer1zero1/expo-responsive-window

Peer dependencies: react >=18, react-native >=0.71.

import { useScreenLayout, ScreenContentInsets } from '@programmer1zero1/expo-responsive-window';

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Table of contents

1. Demo
2. Why this package
3. Roadmap & philosophy
4. Mental model in 30 seconds
5. Reactive vs snapshot — read this first
6. Quick reference: which helper for which style prop?
7. API by use case
   • Read live layout in a screen
   • Scale a single value
   • Pick a value per breakpoint
   • Wrap screen content
   • Configure defaults globally
   • Outside React (worklets / handlers / module scope)
8. Gotchas
9. Settings reference
10. Recipes
11. Explore and learn more →

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Why this package

You design at one canvas (default 430 × 932) and ship across phone, tablet, foldable, web, and desktop. Three things go wrong:

• Fonts and icons explode when scaled by raw windowWidth / 430 on a tablet.
• Vertical lists feel sparse on wide screens because spacing was tuned for phones.
• StyleSheet.create({...}) at module scope freezes any scaled value forever — rotation does nothing.

This package gives you one hook (useScreenLayout) whose helpers fix all three.

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Roadmap & philosophy

This is a first version: it should be useful today, and it will evolve. The goal is to keep improving the API, defaults, and docs as real apps stress-test it—without promising perfection on day one.

Why it exists: a lot of older responsive helpers are unmaintained, deprecated, or too narrow for Expo + React Native across phone, tablet, foldable, web, and desktop. This library was written to cover that versatility in one place: live window dimensions, sensible scaling, breakpoints, and both reactive (components) and snapshot (handlers / worklets) paths.

Nobody ships a flawless layout system—but we can aim for clarity, correctness, and maintainability. If something is missing or feels wrong, issues and PRs are welcome.

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Mental model in 30 seconds

You hand the helpers design pixels (numbers from your design canvas). The hook returns real, current pixels for the live window.

Concept	What it does
width-based ramp (scaledWidth)	Grows with window width up to scalePlateauWidth, capped at scaleMax. Stops fonts blowing up.
height-based ramp (scaledHeight)	Pure ratio against designHeight. No clamp.
vertical compaction (verticalSpacing)	Height ramp × verticalCompactionFactor (≈ 0.72 tablet, 0.92 desktop). Lists feel denser on wide screens.
breakpoints	phone, tablet, desktop — derived from breakpointTablet / breakpointDesktop.

The hook subscribes to useWindowDimensions(), so anything you read from it re-renders on rotation, split view, foldable folds, and web resize.

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Reactive vs snapshot — read this first

The same maths is exposed twice. Pick the wrong one and your screen will not update on rotation.

You're inside…	Use the reactive API	Avoid (will not update)
A React component / screen	useScreenLayout(), useResponsivePick(), <ScreenContentInsets/>	getScreenLayoutSnapshot(), scaledWidthDetached()
Event handler, Reanimated worklet, plain function, non-React module	getScreenLayoutSnapshot(), scaledWidthDetached(), pickByBreakpoint()	useScreenLayout() (hooks rule)
Module-scope StyleSheet.create({...})	None — move styles into the component	All scalers freeze here

Naming rule: anything containing Detached or Snapshot is a one-shot read.

---

Quick reference: which helper for which style prop?

If you know the React Native style property, this table tells you which helper to call.

Style property / use case	Helper	Why
fontSize	scaledWidth(px)	Width ramp is plateau-clamped, so type stays readable on tablets.
Icon size (<Ionicons size={...} />)	scaledWidth(px)	Same ramp as type — they should grow together.
lineHeight	scaledWidth(px)	Tracks the font ramp so leading stays proportional.
borderRadius, borderWidth	scaledWidth(px)	Visually horizontal; should not stretch tall on landscape.
paddingHorizontal, marginHorizontal, gap (in a row), horizontal width	scaledWidth(px)	Width-driven.
height of a header / bar / divider	scaledHeight(px)	Should track screen height, no compaction.
paddingTop / paddingBottom of the screen scroll	verticalSpacing(px)	Compacts on tablet/desktop so more content fits.
gap in a vertical stack of cards	verticalSpacing(px)	Same reasoning — denser rhythm on wide.
paddingBottom of a tab bar	verticalSpacing(px)	Avoids a chunky bar on iPad.
maxWidth / width as a fraction of window	windowWidthPct(percent)	Always live.
Different design px on phone vs tablet vs desktop	scaledWidthAt({ phone, tablet, desktop }) (or scaledHeightAt, verticalSpacingAt, adaptiveSpacingAt)	One call, no if ladders.
Pick any value (number, string, component) per breakpoint	useResponsivePick({ phone, tablet, desktop })	Returns the value for the live breakpoint.
Toggle layout based on size class	isPhone, isTablet, isDesktop, tabletOnly, isPortrait	Plain booleans on the hook.

If you're unsure between scaledHeight and verticalSpacing: a header height is scaledHeight, a list gap is verticalSpacing.

---

API by use case

Read live layout in a screen

import { useScreenLayout } from '@programmer1zero1/expo-responsive-window';

function ProfileCard() {
  const {
    scaledWidth,
    scaledHeight,
    verticalSpacing,
    isTablet,
  } = useScreenLayout();

  return (
    <View
      style={{
        padding: scaledWidth(16),
        borderRadius: scaledWidth(12),
        gap: isTablet ? verticalSpacing(12) : scaledHeight(14),
      }}>
      <Text style={{ fontSize: scaledWidth(15), lineHeight: scaledWidth(22) }}>
        Hi
      </Text>
    </View>
  );
}

When to use: the default. Any component that renders something whose size depends on the window.

Scale a single value

You want to scale…	Call
One pixel value, width/typography/icon	scaledWidth(designPx)
One pixel value, vertical, no compaction	scaledHeight(designPx)
One pixel value, vertical, with compaction	verticalSpacing(designPx)
All scalers also accept (px, { mergeSettings: { ... } })	per-call override

const { scaledWidth } = useScreenLayout();

scaledWidth(16);                                    // normal
scaledWidth(16, { mergeSettings: { scaleMax: 1.4 }}); // tighter cap, this call only

Pick a value per breakpoint

Three flavours, depending on what you're picking.

// Numeric design px → scaled px (use the right ramp for the property)
const radius   = scaledWidthAt({ phone: 12, tablet: 16, desktop: 20 });
const barH     = scaledHeightAt({ phone: 56, tablet: 64 });
const listGap  = verticalSpacingAt({ phone: 16, tablet: 12, desktop: 12 });
const sectionGap = adaptiveSpacingAt({ phone: 24, tablet: 18 }); // phone uses scaledHeight, wide uses verticalSpacing

// Any non-numeric value
import { useResponsivePick } from '@programmer1zero1/expo-responsive-window';

const columns       = useResponsivePick({ phone: 1, tablet: 2, desktop: 3 });
const headerVariant = useResponsivePick({ phone: 'compact', tablet: 'spacious' });

Fallback rule: desktop falls back to tablet, tablet falls back to phone. You only have to provide phone.

Wrap screen content

<ScreenContentInsets/> is width: 100% + maxWidth: contentMaxWidth + paddingHorizontal: horizontalGutter (the right gutter for the live breakpoint).

import { ScreenContentInsets } from '@programmer1zero1/expo-responsive-window';

<ScreenContentInsets adaptiveGap={{ phone: 16, tablet: 12 }}>
  <Card />
  <Card />
  <Card />
</ScreenContentInsets>

Prop	Effect
adaptiveGap	Sets a gap via adaptiveSpacingAt (phone → scaledHeight, wide → verticalSpacing).
verticalGapAtBands	Sets a gap via verticalSpacingAt on every breakpoint. Used only when adaptiveGap is omitted.
horizontalGutterOverride	Forces a specific horizontal padding for this container.
style	Standard ViewStyle, merged last.

Don't add paddingHorizontal on a child of ScreenContentInsets — you'll inset twice.

Configure defaults globally

Wrap once near the root if you want different breakpoints, gutters, or design canvas across the whole app.

import { ScreenLayoutSettingsProvider } from '@programmer1zero1/expo-responsive-window';

<ScreenLayoutSettingsProvider
  settings={{ breakpointTablet: 744, gutterPhone: 16, scaleMax: 1.5 }}>
  <App />
</ScreenLayoutSettingsProvider>

Anything you don't pass is filled from DEFAULT_SCREEN_LAYOUT. Per-call { mergeSettings: ... } still wins on individual calls.

Outside React (worklets / handlers / module scope)

These do not subscribe to dimension changes.

import {
  getScreenLayoutSnapshot,
  scaledWidthDetached,
  pickByBreakpoint,
  windowWidthPct,
} from '@programmer1zero1/expo-responsive-window';

// One-off scaled px (single Dimensions read)
const px = scaledWidthDetached(14);

// Full metrics object, no subscription
const snap = getScreenLayoutSnapshot();
if (snap.isTablet) { /* ... */ }

// Pick a value by an explicit breakpoint
const cols = pickByBreakpoint(snap.breakpoint, { phone: 1, tablet: 2, desktop: 3 });

// Width % with explicit window width (frozen value)
const half = windowWidthPct(50, snap.windowWidth);

When to use: Reanimated worklets, gesture callbacks, analytics, or anywhere you can't legally call a hook.

---

Gotchas

• StyleSheet.create({...}) at module scope freezes scaled values forever. This is a React Native pitfall, not a bug here.

  // bad — runs once at import time, never updates on rotation
  const styles = StyleSheet.create({
    box: { padding: scaledWidthDetached(16) },
  });
  
  // good — recomputed each render
  function Box() {
    const { scaledWidth } = useScreenLayout();
    return <View style={{ padding: scaledWidth(16) }} />;
  }

• One API for layout and type: use scaledWidth for fontSize, icon sizes, and horizontal spacing — there is no separate scaledFont.

• scaledHeight vs verticalSpacing: scaledHeight for fixed bars (header height, divider), verticalSpacing for rhythm (scroll padding, list gaps, tab-bar padding).

• windowWidthPct has two forms. Reactive (from the hook) closes over the live width. Standalone (imported directly) is a one-shot snapshot — pass an explicit windowWidth if you want to freeze it.

• <ScreenContentInsets> already pads horizontally. Don't double-pad children.

---

Settings reference

DEFAULT_SCREEN_LAYOUT ships with sensible values; override only what you need.

Field	Default	Purpose
breakpointTablet	768	windowWidth >= this → isTablet.
breakpointDesktop	1024	windowWidth >= this → isDesktop.
scalePlateauWidth	820	Width at which the width-ramp stops growing.
scaleMax	1.78	Hard cap on the width-ramp.
designWidth	430	Reference canvas width.
designHeight	932	Reference canvas height.
widthClampMin	300	Lower clamp before computing the width-ramp.
gutterPhone	14	horizontalGutter on phone.
gutterTablet	18	horizontalGutter on tablet.
gutterDesktop	20	horizontalGutter on desktop.
tabletVerticalCompact	0.72	verticalCompactionFactor on tablet-only.
desktopVerticalCompact	0.92	verticalCompactionFactor on desktop.

---

Recipes

Card with breakpoint-aware padding & radius

const { scaledWidth, scaledWidthAt, verticalSpacingAt } = useScreenLayout();

<View
  style={{
    padding: scaledWidth(16),
    borderRadius: scaledWidthAt({ phone: 12, tablet: 16 }),
    gap: verticalSpacingAt({ phone: 12, tablet: 10 }),
  }}>
  …
</View>

Scrollable section list

const { verticalSpacing, scaledHeight } = useScreenLayout();

<ScrollView
  contentContainerStyle={{
    paddingTop: verticalSpacing(20),
    paddingBottom: verticalSpacing(40),
    rowGap: verticalSpacing(16),
  }}>
  …
</ScrollView>

Header with fixed bar height + scaled type

const { scaledHeight, scaledWidth } = useScreenLayout();

<View style={{ height: scaledHeight(56), paddingHorizontal: scaledWidth(16) }}>
  <Text style={{ fontSize: scaledWidth(18), lineHeight: scaledWidth(24) }}>Title</Text>
</View>

Two-column on tablet, single on phone

const columns = useResponsivePick({ phone: 1, tablet: 2, desktop: 3 });

<View style={{ flexDirection: 'row', flexWrap: 'wrap' }}>
  {items.map(item => (
    <View key={item.id} style={{ width: `${100 / columns}%` }}>
      <Card item={item} />
    </View>
  ))}
</View>

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Explore and learn more →

• GitHub: github.com/programmer1zero1/expo-responsive-window
• Real-world usage (Expo Go app): github.com/programmer1zero1/my_portfolio — see app/appFlow/(tabs)/*, app/appFlow/(stack)/*, and components/* for production screens that consume useScreenLayout, ScreenContentInsets, scaledWidth, scaledHeight, verticalSpacing, scaledWidthAt, adaptiveSpacingAt, tabletOnly, and windowWidthPct.
• Source (single file you can vendor): src/index.tsx
• Built output: dist/
• AI / agent rules: AGENTS.md — concise rules so Cursor/Claude/Copilot generate correct calls on the first try.
• Issues & PRs: github.com/programmer1zero1/expo-responsive-window/issues — the goal is one place that covers fontSize, layout, vertical rhythm, and breakpoints without sprinkling if (isTablet) through your code.