Fix applying WindowInsets inside Popup/Dialog (#832)

## Proposed Changes

- Unwrap unnecessary state for `LocalSafeArea`/`LocalLayoutMargins`
- Override  `LocalSafeArea`/`LocalLayoutMargins` for separate owners.
- Replace `IOSInsets` to `PlatformInsets` - [Don't use data classes in
an
API](https://kotlinlang.org/docs/jvm-api-guidelines-backward-compatibility.html#don-t-use-data-classes-in-an-api)

## Changes in API

```diff
-androidx.compose.ui.uikit.IOSInsets
+androidx.compose.ui.platform.PlatformInsets
```
```diff
-androidx.compose.ui.uikit.LocalSafeAreaState
+androidx.compose.ui.platform.LocalSafeArea
```
```diff
-androidx.compose.ui.uikit.LocalLayoutMarginsState
+androidx.compose.ui.platform.LocalLayoutMargins
```

## Testing

```kt
Box(modifier = Modifier
    .fillMaxSize()
    .windowInsetsPadding(WindowInsets.systemBars)
    .background(Color.Green)
)
Popup {
    Box(modifier = Modifier
        .fillMaxSize()
        .windowInsetsPadding(WindowInsets.systemBars)
        .background(Color.Red)
    )
}
```

Android | iOS (Before) | iOS (After)
--- | --- | ---
<img
src="https://github.com/JetBrains/compose-multiplatform-core/assets/1836384/8fe492a6-007e-4cbf-9c8a-fa6eea9bb056"
height="600"> | <img
src="https://github.com/JetBrains/compose-multiplatform-core/assets/1836384/3168efba-0072-47aa-853a-1c44bd68e4e0"
height="600"> | <img
src="https://github.com/JetBrains/compose-multiplatform-core/assets/1836384/3845efe8-eb8e-4c71-87e2-ea44dd73a91e"
height="600">

## Issues Fixed

Fixes (partially)
JetBrains/compose-multiplatform#3701

compose/foundation/foundation-layout/src/uikitMain/kotlin/androidx/compose/foundation/layout/WindowInsets.uikit.kt

@@ -18,13 +18,17 @@ package androidx.compose.foundation.layout
 
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.InternalComposeApi
+import androidx.compose.ui.ExperimentalComposeUiApi
+import androidx.compose.ui.platform.LocalLayoutMargins
+import androidx.compose.ui.platform.LocalSafeArea
+import androidx.compose.ui.platform.PlatformInsets
 import androidx.compose.ui.uikit.*
 import androidx.compose.ui.unit.dp
 
 private val ZeroInsets = WindowInsets(0, 0, 0, 0)
 
-@OptIn(InternalComposeApi::class)
-private fun IOSInsets.toWindowInsets() = WindowInsets(
+@OptIn(ExperimentalComposeUiApi::class)
+private fun PlatformInsets.toWindowInsets() = WindowInsets(
     top = top,
     bottom = bottom,
     left = left,
@@ -36,16 +40,16 @@ private fun IOSInsets.toWindowInsets() = WindowInsets(
  */
 private val WindowInsets.Companion.iosSafeArea: WindowInsets
     @Composable
-    @OptIn(InternalComposeApi::class)
-    get() = LocalSafeAreaState.current.value.toWindowInsets()
+    @OptIn(InternalComposeApi::class, ExperimentalComposeUiApi::class)
+    get() = LocalSafeArea.current.toWindowInsets()
 
 /**
  * This insets represents iOS layoutMargins.
  */
 private val WindowInsets.Companion.layoutMargins: WindowInsets
     @Composable
-    @OptIn(InternalComposeApi::class)
-    get() = LocalLayoutMarginsState.current.value.toWindowInsets()
+    @OptIn(InternalComposeApi::class, ExperimentalComposeUiApi::class)
+    get() = LocalLayoutMargins.current.toWindowInsets()
 
 /**
  * An insets type representing the window of a caption bar.

compose/ui/ui/src/notMobileMain/kotlin/androidx/compose/ui/window/RootLayout.notMobile.kt

@@ -17,8 +17,15 @@
 package androidx.compose.ui.window
 
 import androidx.compose.runtime.Composable
-import androidx.compose.ui.unit.Density
+import androidx.compose.runtime.InternalComposeApi
+import androidx.compose.ui.platform.PlatformInsets
 
+@OptIn(InternalComposeApi::class)
 @Composable
-internal actual fun Density.platformPadding(): RootLayoutPadding =
-    RootLayoutPadding.Zero
+internal actual fun platformInsets(): PlatformInsets =
+    PlatformInsets.Zero
+
+@Composable
+internal actual fun platformOwnerContent(content: @Composable () -> Unit) {
+    content()
+}

compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/platform/PlatformInsets.skiko.kt

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package androidx.compose.ui.platform
+
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.Stable
+import androidx.compose.ui.ExperimentalComposeUiApi
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+
+/**
+ * This class represents platform insets.
+ */
+@ExperimentalComposeUiApi
+@Immutable
+class PlatformInsets(
+    @Stable
+    val top: Dp = 0.dp,
+    @Stable
+    val bottom: Dp = 0.dp,
+    @Stable
+    val left: Dp = 0.dp,
+    @Stable
+    val right: Dp = 0.dp,
+) {
+    companion object {
+        val Zero = PlatformInsets(0.dp, 0.dp, 0.dp, 0.dp)
+    }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is PlatformInsets) return false
+
+        if (top != other.top) return false
+        if (bottom != other.bottom) return false
+        if (left != other.left) return false
+        if (right != other.right) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = top.hashCode()
+        result = 31 * result + bottom.hashCode()
+        result = 31 * result + left.hashCode()
+        result = 31 * result + right.hashCode()
+        return result
+    }
+
+    override fun toString(): String {
+        return "PlatformInsets(top=$top, bottom=$bottom, left=$left, right=$right)"
+    }
+}
+
+internal fun PlatformInsets.exclude(insets: PlatformInsets) = PlatformInsets(
+    left = (left - insets.left).coerceAtLeast(0.dp),
+    top = (top - insets.top).coerceAtLeast(0.dp),
+    right = (right - insets.right).coerceAtLeast(0.dp),
+    bottom = (bottom - insets.bottom).coerceAtLeast(0.dp)
+)

compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/window/Dialog.skiko.kt

@@ -35,6 +35,7 @@ import androidx.compose.ui.input.pointer.PointerEventType
 import androidx.compose.ui.input.pointer.PointerInputEvent
 import androidx.compose.ui.layout.Layout
 import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.platform.PlatformInsets
 import androidx.compose.ui.requireCurrent
 import androidx.compose.ui.semantics.dialog
 import androidx.compose.ui.semantics.semantics
@@ -169,15 +170,15 @@ private fun DialogLayout(
     onOutsidePointerEvent: ((PointerInputEvent) -> Unit)? = null,
     content: @Composable () -> Unit
 ) {
+    val platformInsets = platformInsets()
     RootLayout(
         modifier = modifier,
         focusable = true,
         onOutsidePointerEvent = onOutsidePointerEvent
     ) { owner ->
-        val density = LocalDensity.current
         val measurePolicy = rememberDialogMeasurePolicy(
             properties = properties,
-            platformPadding = with(density) { platformPadding() }
+            platformInsets = platformInsets
         ) {
             owner.bounds = it
         }
@@ -191,14 +192,14 @@ private fun DialogLayout(
 @Composable
 private fun rememberDialogMeasurePolicy(
     properties: DialogProperties,
-    platformPadding: RootLayoutPadding,
+    platformInsets: PlatformInsets,
     onBoundsChanged: (IntRect) -> Unit
-) = remember(properties, platformPadding, onBoundsChanged) {
+) = remember(properties, platformInsets, onBoundsChanged) {
     RootMeasurePolicy(
-        platformPadding = platformPadding,
+        platformInsets = platformInsets,
         usePlatformDefaultWidth = properties.usePlatformDefaultWidth
     ) { windowSize, contentSize ->
-        val position = positionWithPadding(platformPadding, windowSize) {
+        val position = positionWithInsets(platformInsets, windowSize) {
             it.center - contentSize.center
         }
         onBoundsChanged(IntRect(position, contentSize))

compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/window/Popup.skiko.kt

@@ -36,8 +36,8 @@ import androidx.compose.ui.input.pointer.PointerInputEvent
 import androidx.compose.ui.layout.Layout
 import androidx.compose.ui.layout.onGloballyPositioned
 import androidx.compose.ui.layout.positionInWindow
-import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.platform.LocalLayoutDirection
+import androidx.compose.ui.platform.PlatformInsets
 import androidx.compose.ui.semantics.popup
 import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.unit.IntOffset
@@ -421,6 +421,7 @@ private fun PopupLayout(
     onOutsidePointerEvent: ((PointerInputEvent) -> Unit)? = null,
     content: @Composable () -> Unit
 ) {
+    val platformInsets = platformInsets()
     var layoutParentBoundsInWindow: IntRect? by remember { mutableStateOf(null) }
     EmptyLayout(Modifier.parentBoundsInWindow { layoutParentBoundsInWindow = it })
     RootLayout(
@@ -429,12 +430,11 @@ private fun PopupLayout(
         onOutsidePointerEvent = onOutsidePointerEvent
     ) { owner ->
         val parentBounds = layoutParentBoundsInWindow ?: return@RootLayout
-        val density = LocalDensity.current
         val layoutDirection = LocalLayoutDirection.current
         val measurePolicy = rememberPopupMeasurePolicy(
             popupPositionProvider = popupPositionProvider,
             properties = properties,
-            platformPadding = with(density) { platformPadding() },
+            platformInsets = platformInsets,
             layoutDirection = layoutDirection,
             parentBounds = parentBounds
         ) {
@@ -461,16 +461,16 @@ private fun Modifier.parentBoundsInWindow(
 private fun rememberPopupMeasurePolicy(
     popupPositionProvider: PopupPositionProvider,
     properties: PopupProperties,
-    platformPadding: RootLayoutPadding,
+    platformInsets: PlatformInsets,
     layoutDirection: LayoutDirection,
     parentBounds: IntRect,
     onBoundsChanged: (IntRect) -> Unit
-) = remember(popupPositionProvider, properties, platformPadding, layoutDirection, parentBounds, onBoundsChanged) {
+) = remember(popupPositionProvider, properties, platformInsets, layoutDirection, parentBounds, onBoundsChanged) {
     RootMeasurePolicy(
-        platformPadding = platformPadding,
+        platformInsets = platformInsets,
         usePlatformDefaultWidth = properties.usePlatformDefaultWidth
     ) { windowSize, contentSize ->
-        var position = positionWithPadding(platformPadding, windowSize) {
+        var position = positionWithInsets(platformInsets, windowSize) {
             popupPositionProvider.calculatePosition(
                 parentBounds, it, layoutDirection, contentSize
             )

compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/window/RootLayout.skiko.kt

@@ -26,8 +26,10 @@ import androidx.compose.ui.Modifier
 import androidx.compose.ui.input.pointer.PointerInputEvent
 import androidx.compose.ui.layout.Layout
 import androidx.compose.ui.layout.MeasurePolicy
+import androidx.compose.ui.layout.MeasureScope
 import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.platform.LocalLayoutDirection
+import androidx.compose.ui.platform.PlatformInsets
 import androidx.compose.ui.platform.SkiaBasedOwner
 import androidx.compose.ui.platform.setContent
 import androidx.compose.ui.requireCurrent
@@ -71,7 +73,9 @@ internal fun RootLayout(
         )
         scene.attach(owner)
         owner to owner.setContent(parent = parentComposition) {
-            content(owner)
+            platformOwnerContent {
+                content(owner)
+            }
         }
     }
     DisposableEffect(Unit) {
@@ -99,12 +103,12 @@ internal fun EmptyLayout(
 )
 
 internal fun RootMeasurePolicy(
-    platformPadding: RootLayoutPadding,
+    platformInsets: PlatformInsets,
     usePlatformDefaultWidth: Boolean,
-    calculatePosition: (windowSize: IntSize, contentSize: IntSize) -> IntOffset,
+    calculatePosition: MeasureScope.(windowSize: IntSize, contentSize: IntSize) -> IntOffset,
 ) = MeasurePolicy {measurables, constraints ->
     val platformConstraints = applyPlatformConstrains(
-        constraints, platformPadding, usePlatformDefaultWidth
+        constraints, platformInsets, usePlatformDefaultWidth
     )
     val placeables = measurables.fastMap { it.measure(platformConstraints) }
     val windowSize = IntSize(constraints.maxWidth, constraints.maxHeight)
@@ -122,13 +126,12 @@ internal fun RootMeasurePolicy(
 
 private fun Density.applyPlatformConstrains(
     constraints: Constraints,
-    platformPadding: RootLayoutPadding,
+    platformInsets: PlatformInsets,
     usePlatformDefaultWidth: Boolean
 ): Constraints {
-    val platformConstraints = constraints.offset(
-        horizontal = -(platformPadding.left + platformPadding.right),
-        vertical = -(platformPadding.top + platformPadding.bottom)
-    )
+    val horizontal = platformInsets.left.roundToPx() + platformInsets.right.roundToPx()
+    val vertical = platformInsets.top.roundToPx() + platformInsets.bottom.roundToPx()
+    val platformConstraints = constraints.offset(-horizontal, -vertical)
     return if (usePlatformDefaultWidth) {
         platformConstraints.constrain(
             platformDefaultConstrains(constraints)
@@ -138,32 +141,30 @@ private fun Density.applyPlatformConstrains(
     }
 }
 
-internal data class RootLayoutPadding(
-    val left: Int,
-    val top: Int,
-    val right: Int,
-    val bottom: Int
-) {
-    companion object {
-        val Zero = RootLayoutPadding(0, 0, 0, 0)
-    }
-}
-
-internal fun positionWithPadding(
-    padding: RootLayoutPadding,
+internal fun MeasureScope.positionWithInsets(
+    insets: PlatformInsets,
     size: IntSize,
     calculatePosition: (size: IntSize) -> IntOffset,
 ): IntOffset {
+    val horizontal = insets.left.roundToPx() + insets.right.roundToPx()
+    val vertical = insets.top.roundToPx() + insets.bottom.roundToPx()
     val sizeWithPadding = IntSize(
-        width = size.width - padding.left - padding.right,
-        height = size.height - padding.top - padding.bottom
+        width = size.width - horizontal,
+        height = size.height - vertical
     )
     val position = calculatePosition(sizeWithPadding)
-    return position + IntOffset(padding.left, padding.top)
+    val offset = IntOffset(
+        x = insets.left.roundToPx(),
+        y = insets.top.roundToPx()
+    )
+    return position + offset
 }
 
 @Composable
-internal expect fun Density.platformPadding(): RootLayoutPadding
+internal expect fun platformInsets(): PlatformInsets
+
+@Composable
+internal expect fun platformOwnerContent(content: @Composable () -> Unit)
 
 private fun Density.platformDefaultConstrains(
     constraints: Constraints

compose/ui/ui/src/uikitMain/kotlin/androidx/compose/ui/uikit/Insets.uikit.kt → compose/ui/ui/src/uikitMain/kotlin/androidx/compose/ui/platform/PlatformInsets.uikit.kt

@@ -14,40 +14,23 @@
  * limitations under the License.
  */
 
-package androidx.compose.ui.uikit
+package androidx.compose.ui.platform
 
-import androidx.compose.runtime.Immutable
 import androidx.compose.runtime.InternalComposeApi
-import androidx.compose.runtime.State
 import androidx.compose.runtime.staticCompositionLocalOf
-import androidx.compose.ui.unit.Dp
-import androidx.compose.ui.unit.dp
 
 /**
  * Composition local for SafeArea of ComposeUIViewController
  */
 @InternalComposeApi
-val LocalSafeAreaState = staticCompositionLocalOf<State<IOSInsets>> {
-    error("CompositionLocal LocalSafeAreaTopState not present")
+val LocalSafeArea = staticCompositionLocalOf<PlatformInsets> {
+    error("CompositionLocal LocalSafeArea not present")
 }
 
 /**
  * Composition local for layoutMargins of ComposeUIViewController
  */
 @InternalComposeApi
-val LocalLayoutMarginsState = staticCompositionLocalOf<State<IOSInsets>> {
-    error("CompositionLocal LocalLayoutMarginsState not present")
+val LocalLayoutMargins = staticCompositionLocalOf<PlatformInsets> {
+    error("CompositionLocal LocalLayoutMargins not present")
 }
-
-/**
- * This class represents iOS Insets.
- * It contains equals and hashcode and can be used as Compose State<IOSInsets>.
- */
-@Immutable
-@InternalComposeApi
-data class IOSInsets(
-    val top: Dp = 0.dp,
-    val bottom: Dp = 0.dp,
-    val left: Dp = 0.dp,
-    val right: Dp = 0.dp,
-)