[Bug report] Hashing image before and after `compressWithFile` results diff depending on the format

[raulmabe-labhouse]

Version

2.3.0

Platforms

dart

Device Model

iPhone 13

flutter info

[✓] Flutter (Channel stable, 3.22.1, on macOS 14.5 23F79 darwin-arm64, locale en-ES)
    • Flutter version 3.22.1 on channel stable at /Users/raulmateo/fvm/versions/3.22.1
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[✓] Connected device (3 available)
    • macOS (desktop)                 • macos                 • darwin-arm64   • macOS 14.5 23F79 darwin-arm64
    • Mac Designed for iPad (desktop) • mac-designed-for-ipad • darwin         • macOS 14.5 23F79 darwin-arm64
    • Chrome (web)                    • chrome                • web-javascript • Google Chrome 126.0.6478.183

[✓] Network resources
    • All expected network resources are available.

• No issues found!

How to reproduce?

Import crypto package.

1. Use sha256 to convert image to hash.
2. Call the compressWithFile method with PNG.
3. Use sha256 to hash the resulting image again
4. Test that the first hash and the second hash are the same.

Now do the same with WEBP, and you'll see the hashes are different.

Logs

No response

Example code (optional)

Future<String> removeExif(String path) async {
    final bytes = await FlutterImageCompress.compressWithFile(path, quality: 100, format: CompressFormat.png);
    final newPath = await FilesMixin.getNewTempPath('tmp', 'png');
    File(newPath).writeAsBytesSync(bytes!);
    return newPath;
  }

  Future<String> generateUniqueImageHash(File file) async {
    final digest = await sha256.bind(file.openRead()).first;
    return digest.toString();
  }

Contact

raul.mateo@labhouse.io