react / react/react-native

Text with italic/bold-italic fonts is horizontally clipped

Aperta
#56,349 1 commento 0 reazioni 0 assegnatari Vedi su GitHub

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Lingua principale
C++
Stelle
127k
Fork
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Merge medio
1g 23h
PR unite (30g)
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Descrizione

Description

Text rendered with italic or bold-italic custom fonts gets horizontally clipped on both iOS and Android. The last glyph on a line is cut off because the text layout measurement is based on advance widths rather than ink bounds (the actual drawn pixel extent of glyphs).

Italic and bold-italic fonts commonly have glyph outlines that overshoot their declared advance width. The platform text layout engines (StaticLayout/BoringLayout on Android, NSLayoutManager.usedRectForTextContainer: on iOS) size the text container using advance widths only, so the rightmost glyph's ink gets clipped by the container boundary.

This is especially visible with:

  • Large font sizes
  • Custom bold-italic fonts with prominent overshoot (e.g. Magistral-BoldItalic)
  • Text views sized with alignSelf: 'flex-start'
Steps to reproduce
  1. Load a custom bold-italic font (e.g. Magistral-BoldItalic)
  2. Render a <Text> component with alignSelf: 'flex-start' so the text view is not stretched to full width
  3. Observe that the rightmost character is clipped horizontally
React Native Version

0.83.2

Affected Platforms

Runtime - Android, Runtime - iOS

Output of npx @react-native-community/cli info
System:
  OS: macOS 15.7.3
  CPU: (16) x64 Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz
  Memory: 1.58 GB / 64.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 23.3.0
    path: /usr/local/bin/node
  Yarn:
    version: 1.22.22
    path: /usr/local/bin/yarn
  npm:
    version: 10.9.0
    path: /usr/local/bin/npm
  Watchman:
    version: 2025.03.10.00
    path: /usr/local/bin/watchman
Managers:
  CocoaPods:
    version: 1.16.2
    path: /usr/local/bin/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 25.2
      - iOS 26.2
      - macOS 26.2
      - tvOS 26.2
      - visionOS 26.2
      - watchOS 26.2
  Android SDK:
    API Levels:
      - "34"
      - "35"
      - "36"
    Build Tools:
      - 32.0.0
      - 33.0.0
      - 34.0.0
      - 35.0.0
      - 36.0.0
    System Images:
      - android-30 | Google Play Intel x86 Atom
      - android-31 | Google APIs Intel x86_64 Atom
      - android-33 | Google Play Intel x86_64 Atom
      - android-34 | Intel x86_64 Atom
      - android-34 | Google APIs Intel x86_64 Atom
      - android-34 | Google Play Intel x86_64 Atom
      - android-35 | ARM 64 v8a
      - android-35 | Intel x86_64 Atom
      - android-35 | Google APIs Intel x86_64 Atom
      - android-35 | Google Play Intel x86_64 Atom
      - android-36 | Google Play Intel x86_64 Atom
      - android-36 | Pre-Release 16 KB Page Size Google Play ARM 64 v8a
      - android-36 | Pre-Release 16 KB Page Size Google Play Intel x86_64 Atom
      - android-36 | Pre-Release 16 KB Page Size Google APIs ARM 64 v8a
      - android-36 | Pre-Release 16 KB Page Size Google APIs Intel x86_64 Atom
    Android NDK: Not Found
IDEs:
  Android Studio: 2025.2 AI-252.25557.131.2521.14432022
  Xcode:
    version: 26.2/17C52
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.13
    path: /usr/bin/javac
  Ruby:
    version: 3.3.5
    path: /usr/local/opt/ruby/bin/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 20.0.0
    wanted: 20.0.0
  react:
    installed: 19.2.0
    wanted: 19.2.0
  react-native:
    installed: 0.83.2
    wanted: 0.83.2
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true
Stacktrace or Logs
no crash
MANDATORY Reproducer

https://snack.expo.dev/@alex_p8/font-overflow-fix

Screenshots and Videos

Expected Behavior

The text container should be wide enough to fully contain the drawn glyphs. The measurement should account for ink bounds (the actual pixel extent of rendered glyphs), not just advance widths.

Actual Behavior

The rightmost glyph on each line is horizontally clipped. The text container is too narrow because it is sized based on advance widths, which do not account for glyph overshoot common in italic and bold-italic typefaces.

Image Image

Guida per i contributori

Apri la guida per i contributori

Come iniziare

  1. Leggi tutta la issue e poi la guida ai contributi del progetto.
  2. Commenta sulla issue per dire che te ne occupi tu — evita che due persone facciano lo stesso lavoro.
  3. Fai un fork del repository e lavora su un branch.
  4. Apri una pull request che faccia riferimento al numero della issue.

Direzione di ricerca

Riproduci il ritaglio con lo Snack collegato, quindi traccia la misurazione del testo di React Native fino a StaticLayout/BoringLayout di Android e NSLayoutManager.usedRectForTextContainer: di iOS. Confronta il contenitore misurato con i limiti dell'inchiostro renderizzati per i font personalizzati in corsivo e grassetto corsivo. Il lavoro è completato quando il glifo più a destra è completamente visibile sia su Android sia su iOS nel caso alignSelf indicato.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Valutazione

Stack tecnologico
android, ios, react-native
Ambito
mobile
Tipo di issue
Bug
Difficoltà
4/5
Tempo stimato
3-5 giorni
Stato di attività
Tranquilla
Chiarezza
Abbastanza chiara
Idoneità per principianti
48/100

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