Assets loaded with ImageDecoder throw a ClassCastException

[colinrtwhite]

Description
Assets decoded via ImageDecoder.createSource(AssetManager assets, String fileName) throw a ClassCastException when loaded inside Paparazzi. This is because PaparazziAssetRepository returns a FileInputStream and ImageDecoder expects an AssetInputStream.

Steps to Reproduce
Attempt to decode an asset with ImageDecoder.createSource(AssetManager assets, String fileName) in Paparazzi.

Expected behavior
PaparazziAssetRepository should return an AssetInputStream from PaparazziAssetRepository.

Additional information:

• Paparazzi Version: 1.3.5
• OS: MacOS
• Compile SDK: 35
• Gradle Version: 8.11.1
• Android Gradle Plugin Version: 8.7.2

[geoff-powell]

So it looks like this is a LayoutLib bug and not specific to Paparazzi. We could potentially fix the issue by making the suggested changes.

You can repro this in Android Studio by creating this preview:

@Paparazzi
@Preview
@Composable
fun Sample() {
  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
    ImageDecoder.createSource(LocalContext.current.assets, "test.png").decodeBitmap { info, source ->

    }
  }
}

I think the real issue is the reliance on the type AssetInputStream in ImageDecoder since the AssetManager.load method only returns type InputStream

[colinrtwhite]

Yep it's definitely bad design on ImageDecoder's part. Worst case we can probably work around this in Coil by checking if the returned input stream is an AssetInputStream ahead of time.