react / react/react-native

[ios] Inverse scale transforms results in pixelated blurred poor resolution views

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API: Transforms Issue: Author Provided Repro Platform: iOS Type: New Architecture
Dominant language
C++
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Avg merge
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Merged PRs (30d)
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Description

Description

We have a production app where we have a pinch gesture handler that allows pinch zooming on a map. When the map is zoomed in (scaled up) the child POIs are scaled down to preserve sizing of POIs. Example, if the parent View is scaled by 100 the child POI View is then scaled by 0.01 to counteract the transform and preserve sizing. This works perfectly on Android; however, IOS results in a very pixelated render of the child POI View. It appears on IOS, when a View has nested scale transforms applied such that they are inverse the resulting render is pixelated. On Android the View appears high resolution as expected. (See screenshots below).

See main code in app/{tabs}/index.jsx of repro.

Related:
https://github.com/facebook/react-native/issues/42837

Steps to reproduce

Both Architectures: Paper & Fabric

IOS

  1. Install dependencies npm install and npx pod-install
  2. Run npx react-native run-ios or npm start and open on ios expo
  3. Notice blurred blue View when it should be a solid red square with blue border (bug)

ANDROID

  1. Install dependencies npm install
  2. Run npx react-native run-android
  3. Notice solid red square with blue border (expected)
React Native Version

0.76.6

Affected Platforms

Runtime - iOS

Output of npx react-native info
System:
  OS: macOS 14.6
  CPU: (16) arm64 Apple M3 Max
  Memory: 145.11 MB / 64.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 18.20.5
    path: ~/.nvm/versions/node/v18.20.5/bin/node
  Yarn:
    version: 1.22.19
    path: /usr/local/bin/yarn
  npm:
    version: 10.8.2
    path: ~/.nvm/versions/node/v18.20.5/bin/npm
  Watchman: Not Found
Managers:
  CocoaPods:
    version: 1.15.2
    path: /Users/marcbourguignon/.rbenv/shims/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 24.1
      - iOS 18.1
      - macOS 15.1
      - tvOS 18.1
      - visionOS 2.1
      - watchOS 11.1
  Android SDK: Not Found
IDEs:
  Android Studio: 2021.2 AI-212.5712.43.2112.8609683
  Xcode:
    version: 16.1/16B40
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.4.1
    path: /Users/marcbourguignon/.sdkman/candidates/java/current/bin/javac
  Ruby:
    version: 2.7.5
    path: /Users/marcbourguignon/.rbenv/shims/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 15.1.3
    wanted: ^15.1.3
  react:
    installed: 18.3.1
    wanted: 18.3.1
  react-native:
    installed: 0.76.6
    wanted: 0.76.6
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: false
iOS:
  hermesEnabled: true
  newArchEnabled: false
Stacktrace or Logs
No crash; rendering bug
Reproducer

https://github.com/wen-kai/expo-sandbox/tree/scale-bug

Screenshots and Videos

Actual (IOS):

Image

Expected (Android):

Image

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the reproducer's app/{tabs}/index.jsx and run the listed iOS steps with React Native 0.76.6 in both Paper and Fabric. Compare the iOS result with Android, focusing on the nested inverse scale transforms. Done means the iOS child view renders as a solid red square with a blue border rather than a blurred, pixelated view.

Written by the indexing model from the issue text.

Assessment

Tech stack
ios, javascript, react-native
Domain
mobile
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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