react / react/react-native

[Android] Using adjustsFontSizeToFit=true sometimes causes font size to be too small.

Aperta
#56,799 5 commenti 2 reazioni 0 assegnatari Vedi su GitHub

Nessuno ha ancora preso questa issue.

Needs: Triage :mag: Platform: Android
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Descrizione

Description

Even when there is no need to shrink the font, there is sometimes a difference in the font sized used when adjustsFontSizeToFit is true vs. when it is false (or not included as a prop on a <Text> component). In other words, the font size is reduced when it should not be. This problem was introduced by the fix for #54715.

Specific font sizes needed to show this bug vary depending on the dp-to-font ratio of the test system or emulator, which points to rounding as the root cause of this bug.

Steps to reproduce
  1. Use two components, one with adjustsFontSizeToFit={true} and one without.
  2. Experiment with different fontSize values until you find one or more where the rendered size differs (even though there is no need to reduce the font to accommodate the text).

The provided reproducer demonstrates the problem.

React Native Version

0.85.2

Affected Platforms

Runtime - Android

Output of npx @react-native-community/cli info
info Fetching system and libraries information...
System:
  OS: macOS 15.7.5
  CPU: (16) x64 Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz
  Memory: 829.41 MB / 40.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 24.11.1
    path: /Users/USER/.nvm/versions/node/v24.11.1/bin/node
  Yarn:
    version: 1.22.22
    path: /Users/USER/.nvm/versions/node/v24.11.1/bin/yarn
  npm:
    version: 11.6.2
    path: /Users/USER/.nvm/versions/node/v24.11.1/bin/npm
  Watchman:
    version: 2026.03.30.00
    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:
      - "27"
      - "28"
      - "29"
      - "30"
      - "31"
      - "34"
      - "35"
      - "36"
      - "36"
    Build Tools:
      - 30.0.3
      - 31.0.0
      - 33.0.0
      - 33.0.2
      - 34.0.0
      - 35.0.0
      - 35.0.1
      - 36.0.0
    System Images:
      - android-27 | Google APIs Intel x86 Atom
      - android-27 | Google Play Intel x86 Atom
      - android-29 | Google APIs Intel x86 Atom
      - android-30 | Google Play Intel x86 Atom
      - android-31 | Google Play Intel x86 Atom_64
      - android-34 | Google APIs Intel x86_64 Atom
      - android-34 | Google Play Intel x86_64 Atom
      - android-35 | Google Play Intel x86_64 Atom
      - android-36.1 | Google Play Intel x86_64 Atom
    Android NDK: Not Found
IDEs:
  Android Studio: Not Found
  Xcode:
    version: 26.2/17C52
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.10
    path: /usr/bin/javac
  Ruby:
    version: 2.6.10
    path: /usr/bin/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 20.1.0
    wanted: 20.1.0
  react:
    installed: 19.2.3
    wanted: 19.2.3
  react-native:
    installed: 0.85.2
    wanted: 0.85.2
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true

info React Native v0.85.3 is now available (your project is running on v0.85.2).
info Changelog: https://github.com/facebook/react-native/releases/tag/v0.85.3
info Diff: https://react-native-community.github.io/upgrade-helper/?from=0.85.2&to=0.85.3
info For more info, check out "https://reactnative.dev/docs/upgrading?os=macos".
Stacktrace or Logs
N/A
MANDATORY Reproducer

https://github.com/MarkCSmith/react-native-issues/blob/master/Android-adjustsFontSizeToFit/RNTesterPlayground.js

Screenshots and Videos

Notice the text rendering differences for the following font sizes: 10, 11, 18, 22.

Image

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Direzione di ricerca

Inizia con il riproduttore obbligatorio in RNTesterPlayground.js e confronta il rendering Android dei componenti Text con e senza adjustsFontSizeToFit alle dimensioni dei caratteri segnalate. Traccia l’implementazione Android di questa prop, concentrandoti sul comportamento di arrotondamento introdotto da #54715. Il lavoro è completato quando le dimensioni dei caratteri renderizzate sono uguali quando non è necessario ridurle, inclusi i casi del riproduttore.

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

Valutazione

Stack tecnologico
android, 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
52/100

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