val scrollState = rememberScrollState()
BoxWithConstraints {

            val partScreen = 3 //screen divider, as the header is an image taking a third of the screen
            val offset = (scrollState.value / partScreen)
            val offsetDp = with(LocalDensity.current) { offset.toDp() }
            val maxHeight = this@BoxWithConstraints.maxHeight / partScreen

            val tobAppBarBackgroundColorAlpha: Float by animateFloatAsState(
                when (scrollState.value) {
                    0f -> {
                        0f
                    }
                    in 0f..maxHeight.value -> {
                        scrollState.value/maxHeight.value
                    }
                    else -> {
                        1f
                    }
                }
            )

            Column(modifier = Modifier
                .fillMaxSize()
                .verticalScroll(scrollState)) {
                CoilImage(
                    modifier = Modifier
                        .preferredHeightIn(max = maxHeight)
                        .fillMaxWidth()
                        .padding(top = offsetDp),
                    data = hikeDetail.picture,
                    contentScale = ContentScale.Crop,
                    contentDescription = null
                )
                ... // content of screen
            }

            TopAppBar(
                modifier = Modifier
                    .fillMaxWidth()
                    .statusBarsPadding(),
                title = {},
                backgroundColor = Color.White.copy(alpha = tobAppBarBackgroundColorAlpha),
                elevation = 0.dp,
                contentColor = MaterialTheme.colors.onSurface,
                navigationIcon = {
                    IconButton(
                        modifier = Modifier.background(
                            color = MaterialTheme.colors.surface,
                            shape = CircleShape
                        ),
                        onClick = { onBackPressed() },
                    ) {
                        Icon(
                            painter = painterResource(id = R.drawable.ic_back),
                            contentDescription = null,
                            tint = MaterialTheme.colors.onSurface,
                        )
                    }
                }
            )
        }

isScrollInProress/isAnimationRunning