After each ComposeScene.render phase, send apply notifications and pe…

…rform the corresponding changes. (#563) # Conflicts: # compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/ComposeScene.skiko.kt
JetBrains · Jun 8, 2023 · a8c7fe3 · a8c7fe3
1 parent 0151fd3
commit a8c7fe3
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diff --git a/compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/ComposeSceneTest.kt b/compose/ui/ui/src/desktopTest/kotlin/androidx/compose/ui/ComposeSceneTest.kt
@@ -39,6 +39,7 @@ import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.Surface
+import androidx.compose.material.Text
 import androidx.compose.material.TextField
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
@@ -57,6 +58,8 @@ import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.drawscope.ContentDrawScope
 import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.graphics.toComposeImageBitmap
+import androidx.compose.ui.graphics.toPixelMap
 import androidx.compose.ui.input.key.Key
 import androidx.compose.ui.input.key.KeyEventType
 import androidx.compose.ui.input.key.keyEvent
@@ -152,6 +155,22 @@ class ComposeSceneTest {
         assertFalse(hasRenders())
     }
 
+    // https://github.com/JetBrains/compose-multiplatform/issues/3137
+    @Test
+    fun `rendering of Text state change`() = renderingTest(width = 400, height = 200) {
+        var text by mutableStateOf("before")
+        setContent {
+            Text(text)
+        }
+        awaitNextRender()
+        val before = surface.makeImageSnapshot().toComposeImageBitmap().toPixelMap().buffer
+
+        text = "after"
+        awaitNextRender()
+        val after = surface.makeImageSnapshot().toComposeImageBitmap().toPixelMap().buffer
+        assertThat(after).isNotEqualTo(before)
+    }
+
     @Test(timeout = 5000)
     fun `rendering of Layout state change`() = renderingTest(width = 40, height = 40) {
         var width by mutableStateOf(10)

diff --git a/compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/ComposeScene.skiko.kt b/compose/ui/ui/src/skikoMain/kotlin/androidx/compose/ui/ComposeScene.skiko.kt
@@ -150,12 +150,10 @@ class ComposeScene internal constructor(
         check(!isClosed) { "ComposeScene is closed" }
         isInvalidationDisabled = true
         val result = try {
-            // We must see the actual state before we will do [block]
-            // TODO(https://github.com/JetBrains/compose-jb/issues/1854) get rid of synchronized.
-            synchronized(GlobalSnapshotManager.sync) {
-                Snapshot.sendApplyNotifications()
-            }
-            snapshotChanges.perform()
+            // Try to get see the up-to-date state before running block
+            // Note that this doesn't guarantee it, if sendApplyNotifications is called concurrently
+            // in a different thread than this code.
+            sendAndPerformSnapshotChanges()
             block()
         } finally {
             isInvalidationDisabled = false
@@ -413,16 +411,26 @@ class ComposeScene internal constructor(
             return mainOwner.contentSize
         }
 
+    /**
+     * Sends any pending apply notifications and performs the changes they cause.
+     */
+    private fun sendAndPerformSnapshotChanges() {
+        Snapshot.sendApplyNotifications()
+        snapshotChanges.perform()
+    }
+
     /**
      * Render the current content on [canvas]. Passed [nanoTime] will be used to drive all
      * animations in the content (or any other code, which uses [withFrameNanos]
      */
     fun render(canvas: Canvas, nanoTime: Long): Unit = postponeInvalidation {
         recomposeDispatcher.flush()
-        frameClock.sendFrame(nanoTime)
+        frameClock.sendFrame(nanoTime) // Recomposition
+        sendAndPerformSnapshotChanges() // Apply changes from recomposition phase to layout phase
         needLayout = false
         forEachOwner { it.measureAndLayout() }
         pointerPositionUpdater.update()
+        sendAndPerformSnapshotChanges()  // Apply changes from layout phase to draw phase
         needDraw = false
         forEachOwner { it.draw(canvas) }
         forEachOwner { it.clearInvalidObservations() }