Performance Test: Spacer vs. Padding

gistfile1.txt

package com.packagename.spacervspadding

import android.os.Bundle
import android.util.Log
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.width
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.outlined.Refresh
import androidx.compose.material3.FloatingActionButton
import androidx.compose.material3.Icon
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp

class MainActivity: ComponentActivity() {
  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContent {
      SpacerVsPadding()
    }
  }
}

const val HEIGHT =  45
const val WIDTH = 70
@Composable
fun SpacerVsPadding() {
  var showContent by remember { mutableStateOf<Boolean?>(null) }
  val paddingModifier = Modifier.padding(end = 1.dp)
  val spacerModifier = Modifier.width(1.dp)
  showContent?.let { padding ->
    if(padding) {
      val startNs = System.nanoTime()
      Column {
        repeat(HEIGHT) {
          Row {
            repeat(WIDTH) {
              Text(text = ".", modifier = paddingModifier)
            }
          }
        }
      }
      val paddingTimeNs = System.nanoTime() - startNs
      Log.d("SpacerVsPadding", "Padding: Total - ${paddingTimeNs}ns")
    } else {
      val startNs = System.nanoTime()
      Column {
        repeat(HEIGHT) {
          Row {
            repeat(WIDTH) {
              Text(text = ".")
              Spacer(modifier = spacerModifier)
            }
          }
        }
      }
      val spacerTimeNs = System.nanoTime() - startNs
      Log.d("SpacerVsPadding", "Spacer: Total - ${spacerTimeNs}ns")
    }
  }
  Box(modifier = Modifier.fillMaxSize()){
    FloatingActionButton(
      onClick = { showContent = if(showContent == false) true else false },
      modifier = Modifier.align(Alignment.BottomEnd)
    ){
      Icon(imageVector = Icons.Outlined.Refresh, contentDescription = "Refresh Icon")
    }
  }
}

@Preview
@Composable
fun PreviewSpacerVsPadding() = SpacerVsPadding()