Excessive Zooming Cluster Stress Test

This React Native app is a minimal reproducible demo built to investigate ghost markers and clustering artifacts in react-native-map-clustering.

🎯 Purpose

To stress-test how map clusters recalculate during extreme zoom in/out cycles combined with random panning.
It helps reproduce and analyze the issue where markers or clusters persist ("ghosts") after camera changes.

🧩 Tech Stack

• react-native
• react-native-maps
• react-native-map-clustering

🧪 What It Does

• Generates 1000 random markers centered around Razová, Czech Republic (49.931305 N, 17.531996 E)
• Runs an automated Excessive Zooming Test that:
  • repeatedly zooms from zoom = 15 → 5 and back
  • adds small random pans at each step
  • returns to the original center
• Uses clusterColor, clusterTextColor, and pinColor for clear visual feedback
• Marker and cluster colors change only when regenerating data, not during the test itself

🕹️ Controls

Button	Action
Run Excessive Zooming Test	performs automated zoom / pan cycles
Regenerate 1k markers	creates new random dataset + color scheme
Toggle Cluster	enables / disables clustering

🧭 Usage

Google Maps API key (Android)

1. Create a key in Google Cloud Console and enable “Maps SDK for Android”.
2. Restrict it to Android apps with:
   • Package name: com.rnmapsghostrepro
   • SHA-1: from ./gradlew signingReport (variant debug)
3. Paste the key directly into the manifest:

<!-- android/app/src/main/AndroidManifest.xml -->
<!-- Google Maps API key -->
<meta-data
  android:name="com.google.android.geo.API_KEY"
  android:value="YOUR_API_KEY_HERE" />

Run

npm install
npx react-native run-android

Then simply tap buttons in the UI.

⚠️ Notes

• The test intentionally pushes clustering updates to their limits.
• On some Android 9 emulators, reloading the app (⌘ R or RR) may crash due to Google Maps SDK’s NullPointerException during teardown — unrelated to app logic but reproducible here.
• Best tested on Android ≥ API 30 or iOS ≥ 15.

🪲 Related issue

This repository was created to reproduce and analyze:

Ghost markers / stale clusters after zoom or camera animation

Feel free to fork it, run your own scenarios, and report findings in the related issue thread.

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MIT License © 2025 Jiří Bílek