mazzouzi

val titleYFirstInterpolatedPoint = lerp(
    headerHeight - titleHeightDp - paddingMedium,
    headerHeight / 2,
    collapseFraction
)

mazzouzi

@Composable
private fun Title(scroll: ScrollState, headerHeightPx: Float, toolbarHeightPx: Float) {
    var titleHeightPx by remember { mutableStateOf(0f) }
    val titleHeightDp = with(LocalDensity.current) { titleHeightPx.toDp() }

    Text(
        text = "New York",
        fontSize = 30.sp,
        fontWeight = FontWeight.Bold,
        modifier = Modifier

mazzouzi

val collapseRange: Float = (headerHeightPx - toolbarHeightPx)
val collapseFraction: Float = (scroll.value / collapseRange).coerceIn(0f, 1f)

mazzouzi

@Composable
private fun Toolbar(scroll: ScrollState, headerHeightPx: Float, toolbarHeightPx: Float) {
    val toolbarBottom = headerHeightPx - toolbarHeightPx
    val showToolbar by remember {
        derivedStateOf { scroll.value >= toolbarBottom }
    }

    AnimatedVisibility(
        visible = showToolbar,
        enter = fadeIn(animationSpec = tween(300)),

mazzouzi

@Composable
private fun Header(scroll: ScrollState, headerHeightPx: Float) {
    Box(modifier = Modifier
        .fillMaxWidth()
        .height(headerHeight)
        .graphicsLayer {
            alpha = (-1f / headerHeightPx) * scroll.value + 1
        }
    )
.

mazzouzi

@Composable
private fun Title() {
    Text(
        text = "New York",
        fontSize = 30.sp,
        fontWeight = FontWeight.Bold
    )
}

mazzouzi

@Composable
private fun Toolbar() {
    TopAppBar(
        modifier = Modifier.background(
            brush = Brush.horizontalGradient(
                listOf(Color(0xff026586), Color(0xff032C45))
            )
        ),
        navigationIcon = {
            IconButton(

mazzouzi

@Composable
private fun Header(scroll: ScrollState, headerHeightPx: Float) {

    Box(modifier = Modifier
        .fillMaxWidth()
        .height(headerHeight)
        .graphicsLayer {
            translationY = -scroll.value.toFloat() / 2f // Parallax effect
        }
    )

mazzouzi

@Composable
private fun Body(scroll: ScrollState) {
    Column(
        horizontalAlignment = Alignment.CenterHorizontally,
        modifier = Modifier.verticalScroll(scroll)
    )
.
.

mazzouzi

val scroll: ScrollState = rememberScrollState(0)