Merge "Introduce ElementStateScope" into main
diff --git a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Scene.kt b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Scene.kt
index af51cee..dc3b612 100644
--- a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Scene.kt
+++ b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/Scene.kt
@@ -73,7 +73,7 @@
 internal class SceneScopeImpl(
     private val layoutImpl: SceneTransitionLayoutImpl,
     private val scene: Scene,
-) : SceneScope {
+) : SceneScope, ElementStateScope by layoutImpl.elementStateScope {
     override val layoutState: SceneTransitionLayoutState = layoutImpl.state
 
     override fun Modifier.element(key: ElementKey): Modifier {
diff --git a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayout.kt b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayout.kt
index b7e2dd1..ebc9099 100644
--- a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayout.kt
+++ b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayout.kt
@@ -131,9 +131,30 @@
  */
 @DslMarker annotation class ElementDsl
 
+/** A scope that can be used to query the target state of an element or scene. */
+interface ElementStateScope {
+    /**
+     * Return the *target* size of [this] element in the given [scene], i.e. the size of the element
+     * when idle, or `null` if the element is not composed and measured in that scene (yet).
+     */
+    fun ElementKey.targetSize(scene: SceneKey): IntSize?
+
+    /**
+     * Return the *target* offset of [this] element in the given [scene], i.e. the size of the
+     * element when idle, or `null` if the element is not composed and placed in that scene (yet).
+     */
+    fun ElementKey.targetOffset(scene: SceneKey): Offset?
+
+    /**
+     * Return the *target* size of [this] scene, i.e. the size of the scene when idle, or `null` if
+     * the scene was never composed.
+     */
+    fun SceneKey.targetSize(): IntSize?
+}
+
 @Stable
 @ElementDsl
-interface BaseSceneScope {
+interface BaseSceneScope : ElementStateScope {
     /** The state of the [SceneTransitionLayout] in which this scene is contained. */
     val layoutState: SceneTransitionLayoutState
 
@@ -415,25 +436,7 @@
     ): Float
 }
 
-interface UserActionDistanceScope : Density {
-    /**
-     * Return the *target* size of [this] element in the given [scene], i.e. the size of the element
-     * when idle, or `null` if the element is not composed and measured in that scene (yet).
-     */
-    fun ElementKey.targetSize(scene: SceneKey): IntSize?
-
-    /**
-     * Return the *target* offset of [this] element in the given [scene], i.e. the size of the
-     * element when idle, or `null` if the element is not composed and placed in that scene (yet).
-     */
-    fun ElementKey.targetOffset(scene: SceneKey): Offset?
-
-    /**
-     * Return the *target* size of [this] scene, i.e. the size of the scene when idle, or `null` if
-     * the scene was never composed.
-     */
-    fun SceneKey.targetSize(): IntSize?
-}
+interface UserActionDistanceScope : Density, ElementStateScope
 
 /** The user action has a fixed [absoluteDistance]. */
 class FixedDistance(private val distance: Dp) : UserActionDistance {
diff --git a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayoutImpl.kt b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayoutImpl.kt
index 25b0895..b1cfdcf 100644
--- a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayoutImpl.kt
+++ b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/SceneTransitionLayoutImpl.kt
@@ -98,6 +98,7 @@
     private val horizontalDraggableHandler: DraggableHandlerImpl
     private val verticalDraggableHandler: DraggableHandlerImpl
 
+    internal val elementStateScope = ElementStateScopeImpl(this)
     private var _userActionDistanceScope: UserActionDistanceScope? = null
     internal val userActionDistanceScope: UserActionDistanceScope
         get() =
diff --git a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/UserActionDistanceScopeImpl.kt b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/UserActionDistanceScopeImpl.kt
index 228d19f..b7abb33 100644
--- a/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/UserActionDistanceScopeImpl.kt
+++ b/packages/SystemUI/compose/scene/src/com/android/compose/animation/scene/UserActionDistanceScopeImpl.kt
@@ -19,15 +19,9 @@
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.unit.IntSize
 
-internal class UserActionDistanceScopeImpl(
+internal class ElementStateScopeImpl(
     private val layoutImpl: SceneTransitionLayoutImpl,
-) : UserActionDistanceScope {
-    override val density: Float
-        get() = layoutImpl.density.density
-
-    override val fontScale: Float
-        get() = layoutImpl.density.fontScale
-
+) : ElementStateScope {
     override fun ElementKey.targetSize(scene: SceneKey): IntSize? {
         return layoutImpl.elements[this]?.sceneStates?.get(scene)?.targetSize.takeIf {
             it != Element.SizeUnspecified
@@ -44,3 +38,13 @@
         return layoutImpl.scenes[this]?.targetSize.takeIf { it != IntSize.Zero }
     }
 }
+
+internal class UserActionDistanceScopeImpl(
+    private val layoutImpl: SceneTransitionLayoutImpl,
+) : UserActionDistanceScope, ElementStateScope by layoutImpl.elementStateScope {
+    override val density: Float
+        get() = layoutImpl.density.density
+
+    override val fontScale: Float
+        get() = layoutImpl.density.fontScale
+}