Hi, I have a little experiment. And I have some question.

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            Greeting("Text")
        }
        lifecycleScope.launch {
            delay(1000)
            repeat(100) {
                delay(10)
                animationPoint.value = animationPoint.value + 1
            }
        }
    }
}

var animationPoint = mutableStateOf(0)

@Composable
fun Greeting(aText: String) {
    Surface(
        modifier = Modifier.offset(
            x = animationPoint.value.dp
        )
    ) {
        Column {
            repeat(40) {
                Text("Text")
            }

        }
    }
}

this will make those Texts from left to right. It seem smooth and without any question. But if I change like this Text content to parameter.

@Composable
fun Greeting(aText: String) {
    Surface(
        modifier = Modifier.offset(
            x = animationPoint.value.dp
        )
    ) {
        Column {
            repeat(40) {
                Text(aText)
            }

        }
    }
}

It will feel lag and obviously has drop some frame. I wonder what difference between those two method ? And If I don't wanna drop frame, How should I do ?

This is due to recomposition, docs does not emphase enough that you should most of the time never use offset(x,y) for animations but offset(offset: Density.() -> IntOffset) as the primer does trigger recomposition and not the second one.

But why dose second one not trigger recomposition？It show no difference with first one for only using parameter.

Read their respective description 😉

Ok . I would try to find clue in description . I just can't get why value and parameter difference can effect modifier's behavior.

It does not affect the modifier behavior, it affects the recomposition. In one case the content is static compose is smart enough to not recompose, in the second case the value is a parameter it does recompose. But the fact that recomposition is skipped with fixed text is side effect it's not what happens in normal case.

Oh.... I got it . Thank you. Happy with your answer. I should put the attention on animation without using offset. 😄

use offset but the right one. It works nicely with the offset { } version.

I would check it, Thank you kindly.