Fix thumbnail theme reads and release 1.3.0-alpha03

README.md

@@ -9,11 +9,11 @@ Composium is an Android Jetpack Compose library for building an in-app UI catalo
 
 One of the core ideas of the library is that it gives you a ready-to-embed `ComposiumScreen()` composable. You can place this screen anywhere in your app: in a debug-only route, a separate activity, an internal tools section, or any custom navigation graph. `ComposiumScreen()` will render the scenes that you described in your project and turn them into a browsable interactive catalog.
 
-Version: `1.3.0-alpha02` (pre-release)
+Version: `1.3.0-alpha03` (pre-release)
 
 Artifacts:
-- `io.github.oleginvoke:composium:1.3.0-alpha02`
-- `io.github.oleginvoke:composium-processor:1.3.0-alpha02`
+- `io.github.oleginvoke:composium:1.3.0-alpha03`
+- `io.github.oleginvoke:composium-processor:1.3.0-alpha03`
 
 It is useful for:
 - design systems and component libraries;
@@ -101,8 +101,8 @@ plugins {
 }
 
 dependencies {
-    implementation("io.github.oleginvoke:composium:1.3.0-alpha02")
-    ksp("io.github.oleginvoke:composium-processor:1.3.0-alpha02")
+    implementation("io.github.oleginvoke:composium:1.3.0-alpha03")
+    ksp("io.github.oleginvoke:composium-processor:1.3.0-alpha03")
 }
 ```
 
@@ -116,7 +116,7 @@ Automatic discovery collects scenes declared in that showcase module; it does no
 
 ```kotlin
 dependencies {
-    implementation("io.github.oleginvoke:composium:1.3.0-alpha02")
+    implementation("io.github.oleginvoke:composium:1.3.0-alpha03")
 }
 ```
 
@@ -409,8 +409,11 @@ Theme commands use `ComposiumScreen`'s existing `onThemeChange` handling. If you
 reflects the effective theme, not a pending request.
 
 Call commands from event handlers or effects, not directly during composition. Commands
-do nothing in thumbnails, `RenderPreview()`, or after the scene leaves composition;
-inactive state objects report `false`. `None` hides the toolbars, not the built-in
+do nothing in thumbnails, `RenderPreview()`, or after the scene leaves composition.
+In thumbnails, `host.theme.isDark` reports the theme used to capture the image;
+controls and eyedropper visibility remain `false`. In `RenderPreview()` or after an
+opened scene leaves composition, state objects report `false`.
+`None` hides the toolbars, not the built-in
 Properties / Environment panel or eyedropper that these commands operate.
 
 ### Closing a scene from your own UI

gradle.properties

@@ -28,7 +28,7 @@ org.gradle.caching=true
 
 # Publishing (used by com.vanniktech.maven.publish)
 GROUP=io.github.oleginvoke
-VERSION_NAME=1.3.0-alpha02
+VERSION_NAME=1.3.0-alpha03
 
 # Maven Central release credentials must not be committed.
 # Provide them via ~/.gradle/gradle.properties or ORG_GRADLE_PROJECT_* env vars:

runtime/src/main/kotlin/composium/SceneToolStates.kt

@@ -54,7 +54,8 @@ class SceneEyedropperState internal constructor() {
  * Observable effective Composium theme and theme change requests, owned by [SceneHost].
  * Commands are for event handlers or effects, not composition, and do nothing in
  * thumbnails, [Scene.RenderPreview], or after the owning scene leaves composition.
- * An inactive state reports [isDark] as false.
+ * Thumbnails report their capture theme through [isDark], while commands remain inactive.
+ * In [Scene.RenderPreview] or after an opened scene leaves composition, [isDark] is false.
  */
 @Stable
 class SceneThemeState internal constructor() {

runtime/src/main/kotlin/composium/scene_thumbnail/SceneThumbnailCaptureHost.kt

@@ -26,6 +26,7 @@ import androidx.compose.ui.viewinterop.AndroidView
 import kotlinx.coroutines.CancellationException
 import oleginvoke.com.composium.SceneEntry
 import oleginvoke.com.composium.SceneScope
+import oleginvoke.com.composium.SceneToolStateBinding
 import oleginvoke.com.composium.ui.theme.ComposiumTheme
 import oleginvoke.com.composium.ui.theme.LocalComposiumThemeController
 import androidx.core.graphics.createBitmap
@@ -53,7 +54,16 @@ internal fun SceneThumbnailCaptureHost(
     val context = LocalContext.current
     val density = LocalDensity.current
     val themeController = LocalComposiumThemeController.current
-    val sceneScope = remember(captureRequest.key) { SceneScope() }
+    val sceneScope = remember(captureRequest.key) {
+        val isDarkTheme = captureRequest.key.isDarkTheme
+        SceneScope().apply {
+            // Read the capture's theme without letting thumbnail effects control the host.
+            host.theme.binding = SceneToolStateBinding(
+                read = { isDarkTheme },
+                change = {},
+            )
+        }
+    }
     val installedContent = remember { SceneThumbnailInstalledContent() }
     var captureView by remember(captureRequest.key) { mutableStateOf<ComposeView?>(null) }
     var captureSurfaceState by remember(captureRequest.key) {

runtime/src/test/kotlin/composium/scene_thumbnail/SceneThumbnailThemeTest.kt

@@ -0,0 +1,138 @@
+package oleginvoke.com.composium.scene_thumbnail
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.size
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.SideEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.toPixelMap
+import androidx.compose.ui.test.junit4.createComposeRule
+import androidx.compose.ui.unit.dp
+import oleginvoke.com.composium.Scene
+import oleginvoke.com.composium.SceneEntry
+import oleginvoke.com.composium.SceneScope
+import oleginvoke.com.composium.ui.theme.ComposiumThemeController
+import oleginvoke.com.composium.ui.theme.LocalComposiumThemeController
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+import org.robolectric.annotation.GraphicsMode
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [35])
+@GraphicsMode(GraphicsMode.Mode.NATIVE)
+class SceneThumbnailThemeTest {
+    @get:Rule
+    val composeRule = createComposeRule()
+
+    @Test
+    fun automaticThumbnailCapturesContentInLightDarkAndLightThemes() {
+        var dark by mutableStateOf(false)
+        val captures = mutableMapOf<Boolean, Color>()
+        val entry = SceneEntry(Scene(null, "Theme-dependent content") {
+            Box(Modifier.size(24.dp).background(if (host.theme.isDark) Color.Blue else Color.Red))
+        })
+        var captureRequest by mutableStateOf<SceneThumbnailCaptureRequest?>(request(entry, dark = false))
+
+        composeRule.setContent {
+            CompositionLocalProvider(
+                LocalComposiumThemeController provides ComposiumThemeController(dark),
+            ) {
+                SceneThumbnailCaptureHost(
+                    request = captureRequest,
+                    onCaptured = { key, result ->
+                        val pixels = result.image.toPixelMap()
+                        captures[key.isDarkTheme] = pixels[pixels.width / 2, pixels.height / 2]
+                        captureRequest = null
+                    },
+                    onFailed = { _, failure -> throw AssertionError(failure.reason, failure.throwable) },
+                )
+            }
+        }
+        advanceCaptureFrames()
+        composeRule.runOnIdle {
+            assertEquals(Color.Red, captures[false])
+            dark = true
+            captureRequest = request(entry, dark = true)
+        }
+        advanceCaptureFrames()
+        composeRule.runOnIdle {
+            assertEquals(Color.Blue, captures[true])
+            captures.remove(false)
+            dark = false
+            captureRequest = request(entry, dark = false)
+        }
+        advanceCaptureFrames()
+        composeRule.runOnIdle { assertEquals(Color.Red, captures[false]) }
+    }
+
+    @Test
+    fun customThumbnailReadsCaptureThemeAndCannotControlTheHost() {
+        var themeRequests = 0
+        var captured = false
+        lateinit var scope: SceneScope
+        val entry = SceneEntry(Scene(
+            group = null,
+            name = "Read-only thumbnail host",
+            thumbnail = {
+                SideEffect { scope = this }
+                Box(Modifier.size(24.dp).background(if (host.theme.isDark) Color.Blue else Color.Red))
+            },
+            content = { error("Custom thumbnail must not execute main content") },
+        ))
+
+        composeRule.setContent {
+            // An in-flight capture must render its key's theme even if the controller differs.
+            CompositionLocalProvider(
+                LocalComposiumThemeController provides ComposiumThemeController(false) { themeRequests++ },
+            ) {
+                SceneThumbnailCaptureHost(
+                    request = request(entry, dark = true),
+                    onCaptured = { _, _ -> captured = true },
+                    onFailed = { _, failure -> throw AssertionError(failure.reason, failure.throwable) },
+                )
+            }
+        }
+        composeRule.waitUntil(timeoutMillis = 5_000) { captured }
+        composeRule.runOnIdle {
+            assertTrue(scope.host.theme.isDark)
+            scope.host.theme.setDark(false)
+            scope.host.theme.toggle()
+            scope.host.controls.show()
+            scope.host.controls.toggle()
+            scope.host.eyedropper.show()
+            scope.host.eyedropper.toggle()
+            scope.host.onBack()
+            scope.host.closeScene()
+            assertEquals(0, themeRequests)
+            assertTrue(scope.host.theme.isDark)
+            assertFalse(scope.host.controls.isVisible)
+            assertFalse(scope.host.eyedropper.isVisible)
+        }
+    }
+
+    private fun request(entry: SceneEntry, dark: Boolean) = SceneThumbnailCaptureRequest(
+        key = SceneThumbnailKey(
+            sceneId = entry.id,
+            isDarkTheme = dark,
+        ),
+        sceneEntry = entry,
+    )
+
+    private fun advanceCaptureFrames() {
+        repeat(12) {
+            composeRule.mainClock.advanceTimeBy(200)
+            composeRule.waitForIdle()
+        }
+    }
+}