How can I set sheetPeekHeight to the height of an item inside it in Jetpack Compose?

Given the example

BottomSheetScaffold(
    sheetContent = {
        LazyColumn(
            state = listState,
            contentPadding = PaddingValues(8.dp),
            verticalArrangement = Arrangement.spacedBy(8.dp),
        ) {
            items(data.items) {
                Card(modifier = Modifier.fillMaxWidth()) {
                    Column {
                        Text(text = it.title)
                        Text(text = it.subtitle)
                        Spacer(modifier = Modifier.height(8.dp))
                        Text(text = it.image)
                    }
                }
            }
        }
    },
    sheetPeekHeight = [...]
) {

}

How can I set sheetPeekHeight to be, for example, 40% of the first Card in the LazyColumn within?

You can try something like:

// Need to remember to allow the value changing to mutate the BottomSheet input variable
var peekHeightPx by remember { mutableStateOf(0) }

BottomSheetScaffold(
    sheetContent = {
        LazyColumn(
            state = listState,
            contentPadding = PaddingValues(8.dp),
            verticalArrangement = Arrangement.spacedBy(8.dp),
        ) {
            var index = 0
            items(data.items) {
                Card(modifier = Modifier
                    .fillMaxWidth()
                    .onGloballyPositioned {
                        if (index++ == 0) {
                            peekHeightPx = (it.size.height * 0.4f).toInt()
                        }
                    }) {
                    Column {
                        Text(text = it.title)
                        Text(text = it.subtitle)
                        Spacer(modifier = Modifier.height(8.dp))
                        Text(text = it.image)
                    }
                }
            }
        }
    },
    // If we don't have a value yet, just render it at the default value
    sheetPeekHeight = if (peekHeightPx == 0) {
        BottomSheetScaffoldDefaults.SheetPeekHeight
    } else {
        // The value from onGloballyPositioned is in px and needs to be converted back to a dp value, and 8 needs to be added for the padding and 8 for the spacing between
        (with(LocalDensity.current) { peekHeightPx / density } + 16).dp
    }
) {

}