Issue with loading the AVIF image

[mrmike]

Context

I've encountered an issue loading the AVIF image using the telephoto library. Interestingly, the same image loads correctly when using AsyncImage from the coil.

After comparing events generated by EventListener from coil and telephoto I've noticed that telephoto only reaches resolveSizeStart event. I suspect that the issue is related to resolving the image size. Further debugging revealed that canvasSize is never emitted b/c filter condition is always false but I have no clue why this is happening 🤔

  val resolved = key(image) {
    image.resolve(
      canvasSize = remember {
        snapshotFlow { canvasSize }.filter { it.isSpecified && !it.isEmpty() }
      }
    )
  }

• Coil version 3.0.4
• Telephoto version 0.14.0
• Android SDK 35

Example

@Composable
fun AvifImageLoader() {
    val image = "https://raw.githubusercontent.com/link-u/avif-sample-images/refs/heads/master/fox.profile0.8bpc.yuv420.avif"

    // Using AsyncImage from Coil works fine
    ZoomableAsyncImage(
        model = image,
        contentDescription = null,
    )
}

[mrmike]

Ok, I think the issue is caused by the fact that BitmapRegionDecoder is not supporting AVIF format

java.io.IOException: Image format not supported
at android.graphics.BitmapRegionDecoder.nativeNewInstance(Native Method)
at android.graphics.BitmapRegionDecoder.newInstance(BitmapRegionDecoder.java:102).   
at me.saket.telephoto.subsamplingimage.FileImageSource.decoder(SubSamplingImageSource.kt:167)
at me.saket.telephoto.subsamplingimage.internal.AndroidImageRegionDecoder$Companion$Factory$1$1.invokeSuspend(AndroidImageRegionDecoder.kt:100)

[saket]

We could disable sub-sampling if BitmapRegionDecoder throws an error. Wanna help me out? I'd start by adding an error reporter here:

telephoto/zoomable-image/core/src/main/kotlin/me/saket/telephoto/zoomable/ZoomableImage.kt

Lines 207 to 211 in 29f9b5a

	val subSamplingState = rememberSubSamplingImageState(
	imageSource = delegate.source,
	zoomableState = state.zoomableState,
	imageOptions = delegate.imageOptions
	)

When a callback to onImageLoadingFailed() is received, ZoomableImage could override its resolved value by a fall-back ZoomableImageSource.PainterDelegate.

[mrmike]

Providing empty SubSamplingImageErrorReporter was enough to make image to load. My assuption is that RealSubSamplingImageState is able to provide state when decoder is not present (just LoadImageTilesEffect is not going to work).

I was getting crash because I was testing on debug build where NoOpInRelease reporter rethrows exception for BuildConfig.DEBUG.

Do you think it is still beneficial to provide falback for ZoomableImageSource.PainterDelegate in that scenario?

[saket]

Lol that is a funny side-effect of the fact that SubSamplingImage() displays a placeholder image generated by Coil. I guess we could change the default error reporter to not crash for situations like this.