refactor: add dynamic font scaling support and integrate ProvideDynamicTypeFontScale across modules

core/accessibility/build.gradle.kts

@@ -1,9 +1,18 @@
 plugins {
     id("gwenedeg.kmp.library")
+    id("gwenedeg.compose")
 }
 
 kotlin {
     androidLibrary {
         namespace = "bzh.ajaury.chombev.core.accessibility"
     }
+
+    sourceSets {
+        commonMain.dependencies {
+            // UI - Compose
+            implementation(libs.compose.runtime)
+            implementation(libs.compose.ui)
+        }
+    }
 }

core/accessibility/src/androidMain/kotlin/bzh/ajaury/chombev/core/accessibility/ui/DynamicTypeFontScale.android.kt

@@ -0,0 +1,7 @@
+package bzh.ajaury.chombev.core.accessibility.ui
+
+import androidx.compose.runtime.Composable
+
+/** No-op: the font scale already follows the system setting. */
+@Composable
+actual fun ProvideDynamicTypeFontScale(content: @Composable () -> Unit) = content()

core/accessibility/src/commonMain/kotlin/bzh/ajaury/chombev/core/accessibility/ui/DynamicTypeFontScale.kt

@@ -0,0 +1,13 @@
+package bzh.ajaury.chombev.core.accessibility.ui
+
+import androidx.compose.runtime.Composable
+
+/**
+ * Applies the system text size to [content] as soon as the user changes it.
+ *
+ * Only needed on iOS, see its implementation. Every Compose scene must be wrapped: the root one
+ * and each dialog or bottom sheet, which iOS renders in a scene of its own that does not inherit
+ * the font scale provided by the root one.
+ */
+@Composable
+expect fun ProvideDynamicTypeFontScale(content: @Composable () -> Unit)

core/accessibility/src/iosMain/kotlin/bzh/ajaury/chombev/core/accessibility/ui/DynamicTypeFontScale.ios.kt

@@ -0,0 +1,80 @@
+package bzh.ajaury.chombev.core.accessibility.ui
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.unit.Density
+import platform.Foundation.NSNotificationCenter
+import platform.Foundation.NSOperationQueue
+import platform.UIKit.UIApplication
+import platform.UIKit.UIContentSizeCategoryAccessibilityExtraExtraExtraLarge
+import platform.UIKit.UIContentSizeCategoryAccessibilityExtraExtraLarge
+import platform.UIKit.UIContentSizeCategoryAccessibilityExtraLarge
+import platform.UIKit.UIContentSizeCategoryAccessibilityLarge
+import platform.UIKit.UIContentSizeCategoryAccessibilityMedium
+import platform.UIKit.UIContentSizeCategoryDidChangeNotification
+import platform.UIKit.UIContentSizeCategoryExtraExtraExtraLarge
+import platform.UIKit.UIContentSizeCategoryExtraExtraLarge
+import platform.UIKit.UIContentSizeCategoryExtraLarge
+import platform.UIKit.UIContentSizeCategoryExtraSmall
+import platform.UIKit.UIContentSizeCategoryLarge
+import platform.UIKit.UIContentSizeCategoryMedium
+import platform.UIKit.UIContentSizeCategorySmall
+
+/**
+ * Applies the system text size (Dynamic Type) to [content] as soon as the user changes it.
+ *
+ * Compose Multiplatform reads the font scale once, when the Compose scene is created, so a change
+ * made in the iOS settings only shows once the scene is created again: after the app restarts for
+ * the root scene, or when it is opened again for a dialog or bottom sheet. Workaround for CMP-10365
+ * (https://youtrack.jetbrains.com/issue/CMP-10365), fixed in Compose Multiplatform 1.13.0: remove
+ * it once the project is upgraded.
+ */
+@Composable
+actual fun ProvideDynamicTypeFontScale(content: @Composable () -> Unit) {
+    var contentSizeCategory by remember {
+        mutableStateOf(UIApplication.sharedApplication.preferredContentSizeCategory)
+    }
+
+    DisposableEffect(Unit) {
+        val notificationCenter = NSNotificationCenter.defaultCenter
+        val observer = notificationCenter.addObserverForName(
+            name = UIContentSizeCategoryDidChangeNotification,
+            `object` = null,
+            queue = NSOperationQueue.mainQueue,
+        ) { _ ->
+            contentSizeCategory = UIApplication.sharedApplication.preferredContentSizeCategory
+        }
+        onDispose { notificationCenter.removeObserver(observer) }
+    }
+
+    val density = LocalDensity.current
+    // Only the font scale is overridden: the pixel density stays the one Compose computed.
+    val fontScale = contentSizeCategoryToFontScale[contentSizeCategory] ?: density.fontScale
+    CompositionLocalProvider(
+        LocalDensity provides Density(density = density.density, fontScale = fontScale),
+        content = content,
+    )
+}
+
+// Same mapping as Compose Multiplatform (`uiContentSizeCategoryToFontScaleMap`, which is private),
+// so that the font scale matches the one Compose computes when the scene is created.
+private val contentSizeCategoryToFontScale = mapOf(
+    UIContentSizeCategoryExtraSmall to 0.8f,
+    UIContentSizeCategorySmall to 0.85f,
+    UIContentSizeCategoryMedium to 0.9f,
+    UIContentSizeCategoryLarge to 1f,
+    UIContentSizeCategoryExtraLarge to 1.1f,
+    UIContentSizeCategoryExtraExtraLarge to 1.2f,
+    UIContentSizeCategoryExtraExtraExtraLarge to 1.3f,
+    UIContentSizeCategoryAccessibilityMedium to 1.4f,
+    UIContentSizeCategoryAccessibilityLarge to 1.5f,
+    UIContentSizeCategoryAccessibilityExtraLarge to 1.6f,
+    UIContentSizeCategoryAccessibilityExtraExtraLarge to 1.7f,
+    UIContentSizeCategoryAccessibilityExtraExtraExtraLarge to 1.8f,
+)

core/accessibility/src/jvmMain/kotlin/bzh/ajaury/chombev/core/accessibility/ui/DynamicTypeFontScale.jvm.kt

@@ -0,0 +1,7 @@
+package bzh.ajaury.chombev.core.accessibility.ui
+
+import androidx.compose.runtime.Composable
+
+/** No-op: the font scale already follows the system setting. */
+@Composable
+actual fun ProvideDynamicTypeFontScale(content: @Composable () -> Unit) = content()

core/accessibility/src/webMain/kotlin/bzh/ajaury/chombev/core/accessibility/ui/DynamicTypeFontScale.web.kt

@@ -0,0 +1,7 @@
+package bzh.ajaury.chombev.core.accessibility.ui
+
+import androidx.compose.runtime.Composable
+
+/** No-op: the font scale already follows the system setting. */
+@Composable
+actual fun ProvideDynamicTypeFontScale(content: @Composable () -> Unit) = content()

feature/onboarding/build.gradle.kts

@@ -13,6 +13,9 @@ kotlin {
             implementation(libs.compose.uiToolingPreview)
         }
         commonMain.dependencies {
+            // Core modules
+            implementation(projects.core.accessibility)
+
             // Data modules
             implementation(projects.data.preferences)
             implementation(projects.data.resources)

feature/onboarding/src/commonMain/kotlin/bzh/ajaury/chombev/onboarding/ui/OnboardingScreen.kt

@@ -33,6 +33,7 @@ import androidx.compose.ui.unit.dp
 import androidx.compose.ui.window.Dialog
 import androidx.compose.ui.window.DialogProperties
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import bzh.ajaury.chombev.core.accessibility.ui.ProvideDynamicTypeFontScale
 import bzh.ajaury.chombev.onboarding.model.OnboardingLevel
 import bzh.ajaury.chombev.onboarding.ui.components.OnboardingInfoPage
 import bzh.ajaury.chombev.onboarding.ui.components.OnboardingLevelPage
@@ -90,6 +91,7 @@ fun OnboardingScreen(
             // The content sizes itself against the window rather than the platform default width.
             properties = DialogProperties(usePlatformDefaultWidth = false),
         ) {
+            ProvideDynamicTypeFontScale {
                 Surface(
                     modifier = Modifier
                         .sizeIn(maxWidth = DIALOG_MAX_WIDTH, maxHeight = DIALOG_MAX_HEIGHT)
@@ -105,6 +107,7 @@ fun OnboardingScreen(
                     )
                 }
             }
+        }
     } else {
         Scaffold { innerPadding ->
             OnboardingContent(

feature/records/src/commonMain/kotlin/bzh/ajaury/chombev/player/ui/PlaybackSpeedBottomSheet.kt

@@ -14,6 +14,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
+import bzh.ajaury.chombev.core.accessibility.ui.ProvideDynamicTypeFontScale
 import bzh.ajaury.chombev.player.ui.components.LabeledSlider
 import bzh.ajaury.chombev.preferences.model.PlaybackPreferences
 import bzh.ajaury.chombev.preferences.ui.PreferenceToggle
@@ -50,6 +51,7 @@ fun PlaybackSpeedBottomSheet(
         onDismissRequest = onDismiss,
         sheetState = sheetState,
     ) {
+        ProvideDynamicTypeFontScale {
             PlaybackSpeedContent(
                 speed = speed,
                 breakSeconds = breakSeconds,
@@ -60,6 +62,7 @@ fun PlaybackSpeedBottomSheet(
             )
         }
     }
+}
 
 @Composable
 private fun PlaybackSpeedContent(

feature/records/src/commonMain/kotlin/bzh/ajaury/chombev/preferences/ui/SubtitlePreferencesBottomSheet.kt

@@ -32,6 +32,7 @@ import androidx.compose.ui.semantics.setProgress
 import androidx.compose.ui.semantics.stateDescription
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
+import bzh.ajaury.chombev.core.accessibility.ui.ProvideDynamicTypeFontScale
 import bzh.ajaury.chombev.preferences.model.SubtitlePreferences
 import bzh.ajaury.chombev.resources.generated.resources.Res
 import bzh.ajaury.chombev.resources.generated.resources.subtitle_marked_letters_description
@@ -68,6 +69,7 @@ fun SubtitlePreferencesBottomSheet(
         onDismissRequest = onDismiss,
         sheetState = sheetState,
     ) {
+        ProvideDynamicTypeFontScale {
             SubtitlePreferencesContent(
                 subtitlePreferences = subtitlePreferences,
                 onShowTranscriptionChange = onShowTranscriptionChange,
@@ -78,6 +80,7 @@ fun SubtitlePreferencesBottomSheet(
             )
         }
     }
+}
 
 @Composable
 private fun SubtitlePreferencesContent(

shared/build.gradle.kts

@@ -35,6 +35,7 @@ kotlin {
         }
         commonMain.dependencies {
             // Core modules
+            implementation(projects.core.accessibility)
             implementation(projects.core.coroutines)
             implementation(projects.core.logging)
             implementation(projects.core.model)

shared/src/iosMain/kotlin/bzh/ajaury/chombev/MainViewController.kt

@@ -1,6 +1,12 @@
 package bzh.ajaury.chombev
 
 import androidx.compose.ui.window.ComposeUIViewController
+import bzh.ajaury.chombev.core.accessibility.ui.ProvideDynamicTypeFontScale
 
 @Suppress("ktlint:standard:function-naming")
-fun MainViewController() = ComposeUIViewController { App() }
+fun MainViewController() =
+    ComposeUIViewController {
+        ProvideDynamicTypeFontScale {
+            App()
+        }
+    }