AsyncImage inside LazyColumn doesn't render

[ben-gooding-sky]

Description
When putting an AsyncImage inside a LazyColumn, causes it not to paint.
It goes away if you put it in a regular Column

Steps to Reproduce

LazyColumn {
   items(listOf(1,2,3)) {
      AsyncImage(...)
   }
}

Expected behavior
Image gets rendered in snapshot

Additional information:

• Paparazzi Version: 1.3.1
• OS: MacOS (Apple Silicon)
• Compile SDK: 17.0.7
• Gradle Version: 8.3
• Android Gradle Plugin Version:

[gamepro65]

Is this referring to coil.compose.AsyncImage?

When Paparazzi takes a snapshot of a ComposeView, we first run a composition when attaching ComposeView to the hierarchy, then execute any pending Handler callbacks, and finally tell Layoutlib to take a snapshot which internally calls measure / draw.

If we look at AsyncImagePainter, we see they update their internal painter with Dispatchers.Main.immediate which is backed by a Handler. In the case of Column, this call to Dispatchers.Main.immediate will be queued during that initial composition and will then run when we execute pending Handler callbacks. However, with LazyColumn items are not composed until the measure pass so it can figure out how many items to render. In this case, unfortunately, we cannot force the Handler to execute any pending callbacks before drawing and so the painter misses the first draw call. If you call the gif API with the same setup, I'd imagine the 2nd frame would show the image.

I'd suggest opening an issue with Coil to expose a configuration option for that Dispatcher so you can seed Dispatchers.Unconfined which will synchronously set the painter in time for the first draw.

[jrodbx]

Closing as the issue is unrelated to Paparazzi