Clean up the questDetail parallax

app/src/main/java/com/pixelized/rplexicon/ui/composable/remember/rememberCurrentOffset.kt

@@ -1,35 +0,0 @@
-package com.pixelized.rplexicon.ui.composable.remember
-
-import androidx.compose.foundation.lazy.LazyListState
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.LaunchedEffect
-import androidx.compose.runtime.State
-import androidx.compose.runtime.derivedStateOf
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.remember
-
-/**
- * https://stackoverflow.com/questions/73333935/current-scroll-position-value-in-pixels-in-lazycolumn-jetpack-compose
- */
-@Composable
-fun rememberCurrentOffset(state: LazyListState): State<Int> {
-    val position = remember { derivedStateOf { state.firstVisibleItemIndex } }
-    val itemOffset = remember { derivedStateOf { state.firstVisibleItemScrollOffset } }
-    val lastPosition = rememberPrevious(position.value)
-    val lastItemOffset = rememberPrevious(itemOffset.value)
-    val currentOffset = remember { mutableStateOf(0) }
-
-    LaunchedEffect(position.value, itemOffset.value) {
-        if (lastPosition == null || position.value == 0) {
-            currentOffset.value = itemOffset.value
-        } else if (lastPosition == position.value) {
-            currentOffset.value += (itemOffset.value - (lastItemOffset ?: 0))
-        } else if (lastPosition > position.value) {
-            currentOffset.value -= (lastItemOffset ?: 0)
-        } else { // lastPosition.value < position.value
-            currentOffset.value += itemOffset.value
-        }
-    }
-
-    return currentOffset
-}

app/src/main/java/com/pixelized/rplexicon/ui/composable/remember/rememberLazyListOffset.kt

@@ -0,0 +1,39 @@
+package com.pixelized.rplexicon.ui.composable.remember
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Stable
+import androidx.compose.runtime.State
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.input.nestedscroll.NestedScrollConnection
+import androidx.compose.ui.input.nestedscroll.NestedScrollSource
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+
+@Stable
+data class LazyListOffset(
+    val offsetY: State<Dp>,
+    val connection: NestedScrollConnection,
+)
+
+@Composable
+@Stable
+fun rememberLazyListOffset(): LazyListOffset {
+    val density = LocalDensity.current
+
+    return remember {
+        val offsetY = mutableStateOf(0.dp)
+
+        LazyListOffset(
+            offsetY = offsetY,
+            connection = object : NestedScrollConnection {
+                override fun onPreScroll(available: Offset, source: NestedScrollSource): Offset {
+                    offsetY.value -= with(density) { available.y.toDp() }
+                    return Offset.Zero
+                }
+            },
+        )
+    }
+}

app/src/main/java/com/pixelized/rplexicon/ui/composable/remember/rememberPrevious.kt

@@ -1,21 +0,0 @@
-package com.pixelized.rplexicon.ui.composable.remember
-
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.SideEffect
-
-@Composable
-fun <T> rememberPrevious(
-    current: T,
-    shouldUpdate: (prev: T?, curr: T) -> Boolean = { a: T?, b: T -> a != b },
-): T? {
-    val ref = rememberRef<T>()
-
-    // launched after render, so the current render will have the old value anyway
-    SideEffect {
-        if (shouldUpdate(ref.value, current)) {
-            ref.value = current
-        }
-    }
-
-    return ref.value
-}

app/src/main/java/com/pixelized/rplexicon/ui/composable/remember/rememberRef.kt

@@ -1,23 +0,0 @@
-package com.pixelized.rplexicon.ui.composable.remember
-
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.MutableState
-import androidx.compose.runtime.remember
-
-/**
- * Returns a dummy MutableState that does not cause render when setting it
- */
-@Composable
-fun <T> rememberRef(): MutableState<T?> {
-    // for some reason it always recreated the value with vararg keys,
-    // leaving out the keys as a parameter for remember for now
-    return remember {
-        object : MutableState<T?> {
-            override var value: T? = null
-
-            override fun component1(): T? = value
-
-            override fun component2(): (T?) -> Unit = { value = it }
-        }
-    }
-}

app/src/main/java/com/pixelized/rplexicon/ui/screens/quest/detail/QuestDetailScreen.kt

@@ -14,7 +14,6 @@ import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.offset
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
-import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.material3.ExperimentalMaterial3Api
@@ -36,8 +35,8 @@ import androidx.compose.ui.composed
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.ColorFilter
 import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.input.nestedscroll.nestedScroll
 import androidx.compose.ui.layout.ContentScale
-import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.AnnotatedString
@@ -52,7 +51,8 @@ import androidx.compose.ui.unit.dp
 import androidx.hilt.navigation.compose.hiltViewModel
 import com.pixelized.rplexicon.R
 import com.pixelized.rplexicon.ui.composable.BackgroundImage
-import com.pixelized.rplexicon.ui.composable.remember.rememberCurrentOffset
+import com.pixelized.rplexicon.ui.composable.remember.LazyListOffset
+import com.pixelized.rplexicon.ui.composable.remember.rememberLazyListOffset
 import com.pixelized.rplexicon.ui.navigation.LocalScreenNavHost
 import com.pixelized.rplexicon.ui.theme.LexiconTheme
 import com.pixelized.rplexicon.utilitary.extentions.lexicon
@@ -179,14 +179,17 @@ private fun QuestDetailContent(
             )
         },
         content = { padding ->
+            val lazyListOffset = rememberLazyListOffset()
             Surface(
-                modifier = Modifier.padding(padding),
+                modifier = Modifier
+                    .padding(padding)
+                    .nestedScroll(lazyListOffset.connection),
             ) {
                 BackgroundImage(
                     modifier = Modifier
                         .fillMaxWidth()
                         .aspectRatio(ratio = 1f)
-                        .scrollOffset(scrollState = state) { -it / 2 },
+                        .scrollOffset(scrollState = lazyListOffset) { -it / 2 },
                     model = { annotatedQuest.background },
                 )
                 LazyColumn(
@@ -327,12 +330,10 @@ private fun QuestDetailContent(
 
 @Stable
 private fun Modifier.scrollOffset(
-    scrollState: LazyListState,
+    scrollState: LazyListOffset,
     block: (Dp) -> Dp
 ): Modifier = composed {
-    val scroll = rememberCurrentOffset(scrollState)
+    this.offset(y = block(scrollState.offsetY.value))
-    val density = LocalDensity.current
-    this.offset(y = with(density) { block(scroll.value.toDp()) })
 }
 
 @Composable