Demonstration of how Preview works with a background, across themes, and using MaterialTheme and Surface

DefaultPreviews.kt

package com.example.c5inco

import android.content.res.Configuration.UI_MODE_NIGHT_YES
import androidx.compose.foundation.isSystemInDarkTheme
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.darkColorScheme
import androidx.compose.material3.lightColorScheme
import androidx.compose.runtime.Composable
import androidx.compose.ui.tooling.preview.Preview

@PreviewsWithBackground
@PreviewsWithNoBackground
@Composable
fun PreviewWithNoThemeOrSurface() {
    Greeting()
}

@PreviewsWithBackground
@PreviewsWithNoBackground
@Composable
fun PreviewWithThemeNoSurface() {
    MaterialTheme(
        colorScheme =  if (isSystemInDarkTheme()) darkColorScheme() else lightColorScheme()
    ) {
        Greeting()
    }
}

@PreviewsWithBackground
@PreviewsWithNoBackground
@Composable
fun PreviewWithThemeAndSurface() {
    MaterialTheme(
        colorScheme =  if (isSystemInDarkTheme()) darkColorScheme() else lightColorScheme()
    ) {
        Surface {
            Greeting()
        }
    }
}

@Composable
fun Greeting() {
    Text("Hello")
}

@Preview(name = "BG, Dark", showBackground = true, uiMode = UI_MODE_NIGHT_YES)
@Preview(name = "BG, Light", showBackground = true)
annotation class PreviewsWithBackground

@Preview(name = "No BG, Dark", uiMode = UI_MODE_NIGHT_YES)
@Preview("No BG, Light")
annotation class PreviewsWithNoBackground