adds easing animations to the zoom button controls

feature/camera/src/androidTest/java/com/android/developers/androidify/camera/CameraScreenTest.kt

@@ -58,7 +58,7 @@ class CameraScreenTest {
                 requestFlipCamera = {},
                 defaultZoomOptions = listOf(1f),
                 zoomLevel = { 1f },
-                onChangeZoomLevel = {},
+                onAnimateZoom = {},
                 requestCaptureImage = {},
             )
         }
@@ -79,7 +79,7 @@ class CameraScreenTest {
                 requestFlipCamera = {},
                 defaultZoomOptions = listOf(1f),
                 zoomLevel = { 1f },
-                onChangeZoomLevel = {},
+                onAnimateZoom = {},
                 requestCaptureImage = {},
             )
         }
@@ -102,7 +102,7 @@ class CameraScreenTest {
                 requestFlipCamera = {},
                 defaultZoomOptions = listOf(1f),
                 zoomLevel = { 1f },
-                onChangeZoomLevel = {},
+                onAnimateZoom = {},
             )
         }
 
@@ -124,7 +124,7 @@ class CameraScreenTest {
                 requestFlipCamera = {},
                 defaultZoomOptions = listOf(1f),
                 zoomLevel = { 1f },
-                onChangeZoomLevel = {},
+                onAnimateZoom = {},
                 requestCaptureImage = {},
             )
         }
@@ -145,7 +145,7 @@ class CameraScreenTest {
                 requestFlipCamera = {},
                 defaultZoomOptions = listOf(1f),
                 zoomLevel = { 1f },
-                onChangeZoomLevel = {},
+                onAnimateZoom = {},
                 requestCaptureImage = {},
             )
         }
@@ -168,7 +168,7 @@ class CameraScreenTest {
                 detectedPose = true,
                 defaultZoomOptions = listOf(1f),
                 zoomLevel = { 1f },
-                onChangeZoomLevel = {},
+                onAnimateZoom = {},
                 requestCaptureImage = {},
             )
         }
@@ -193,7 +193,7 @@ class CameraScreenTest {
                 canFlipCamera = true,
                 requestFlipCamera = {},
                 detectedPose = true,
-                onChangeZoomLevel = {},
+                onAnimateZoom = {},
                 requestCaptureImage = {},
             )
         }
@@ -215,7 +215,7 @@ class CameraScreenTest {
                 canFlipCamera = true,
                 requestFlipCamera = {},
                 detectedPose = true,
-                onChangeZoomLevel = {},
+                onAnimateZoom = {},
                 requestCaptureImage = {},
             )
         }
@@ -235,7 +235,7 @@ class CameraScreenTest {
                 viewfinder = dummyViewfinder,
                 defaultZoomOptions = zoomOptions,
                 zoomLevel = { 1.0f }, // Start at second option to ensure first button click changes it
-                onChangeZoomLevel = { changedZoomLevel = it }, // Callback to test
+                onAnimateZoom = { changedZoomLevel = it }, // Callback to test
                 // Default values for other params
                 canFlipCamera = true,
                 requestFlipCamera = {},
@@ -261,7 +261,7 @@ class CameraScreenTest {
                 viewfinder = dummyViewfinder,
                 defaultZoomOptions = zoomOptions,
                 zoomLevel = { 0.6f }, // Start at first option
-                onChangeZoomLevel = { changedZoomLevel = it }, // Callback to test
+                onAnimateZoom = { changedZoomLevel = it }, // Callback to test
                 // Default values for other params
                 canFlipCamera = true,
                 requestFlipCamera = {},
@@ -289,7 +289,7 @@ class CameraScreenTest {
                 requestFlipCamera = {},
                 defaultZoomOptions = listOf(1f),
                 zoomLevel = { 1f },
-                onChangeZoomLevel = {},
+                onAnimateZoom = {},
                 requestCaptureImage = {},
             )
         }
@@ -310,7 +310,7 @@ class CameraScreenTest {
                 requestFlipCamera = {},
                 defaultZoomOptions = listOf(1f),
                 zoomLevel = { 1f },
-                onChangeZoomLevel = {},
+                onAnimateZoom = {},
                 requestCaptureImage = {},
             )
         }

feature/camera/src/main/java/com/android/developers/androidify/camera/CameraControls.kt

@@ -35,7 +35,7 @@ internal fun CameraControls(
     detectedPose: Boolean,
     defaultZoomOptions: List<Float>,
     zoomLevel: () -> Float,
-    onChangeZoomLevel: (Float) -> Unit,
+    onZoomLevelSelected: (Float) -> Unit,
     modifier: Modifier = Modifier,
 ) {
     Column(
@@ -45,7 +45,7 @@ internal fun CameraControls(
         ZoomToolbar(
             defaultZoomOptions = defaultZoomOptions,
             zoomLevel = zoomLevel,
-            onZoomLevelChanged = onChangeZoomLevel,
+            onZoomLevelSelected = onZoomLevelSelected
         )
         Spacer(Modifier.height(12.dp))
         Row(verticalAlignment = Alignment.CenterVertically) {
@@ -74,8 +74,8 @@ private fun CameraControlsPreview() {
             canFlipCamera = true,
             flipCameraDirectionClicked = { },
             detectedPose = true,
-            zoomLevel = { 0.4f },
-            onChangeZoomLevel = { },
+            zoomLevel = {0.4f},
+            onZoomLevelSelected = {},
             defaultZoomOptions = listOf(.6f, 1f),
         )
     }

feature/camera/src/main/java/com/android/developers/androidify/camera/CameraScreen.kt

@@ -130,6 +130,7 @@ fun CameraPreviewScreen(
 
                 uiState.surfaceRequest?.let { surface ->
                     CameraPreviewContent(
+                        modifier = Modifier.fillMaxSize(),
                         surfaceRequest = surface,
                         autofocusUiState = uiState.autofocusUiState,
                         tapToFocus = viewModel::tapToFocus,
@@ -138,13 +139,14 @@ fun CameraPreviewScreen(
                         requestFlipCamera = viewModel::flipCameraDirection,
                         canFlipCamera = uiState.canFlipCamera,
                         requestCaptureImage = viewModel::captureImage,
+                        zoomRange = uiState.zoomMinRatio..uiState.zoomMaxRatio,
                         zoomLevel = { uiState.zoomLevel },
                         onChangeZoomLevel = viewModel::setZoomLevel,
                         foldingFeature = foldingFeature,
-                        modifier = Modifier.fillMaxSize(),
                         shouldShowRearCameraFeature = viewModel::shouldShowRearDisplayFeature,
                         toggleRearCameraFeature = { viewModel.toggleRearDisplayFeature(activity) },
                         isRearCameraEnabled = uiState.isRearCameraActive,
+                        cameraSessionId = uiState.cameraSessionId
                     )
                 }
             } else {
@@ -198,7 +200,7 @@ fun StatelessCameraPreviewContent(
     detectedPose: Boolean,
     defaultZoomOptions: List<Float>,
     zoomLevel: () -> Float,
-    onChangeZoomLevel: (Float) -> Unit,
+    onAnimateZoom: (Float) -> Unit,
     requestCaptureImage: () -> Unit,
     modifier: Modifier = Modifier,
     foldingFeature: FoldingFeature? = null,
@@ -238,9 +240,9 @@ fun StatelessCameraPreviewContent(
         zoomButton = { zoomModifier ->
             ZoomToolbar(
                 defaultZoomOptions = defaultZoomOptions,
-                zoomLevel = zoomLevel,
-                onZoomLevelChanged = onChangeZoomLevel,
+                onZoomLevelSelected = onAnimateZoom,
                 modifier = zoomModifier,
+                zoomLevel = zoomLevel,
             )
         },
         guideText = { guideTextModifier ->
@@ -287,19 +289,29 @@ private fun CameraPreviewContent(
     surfaceRequest: SurfaceRequest,
     autofocusUiState: AutofocusUiState,
     tapToFocus: (Offset) -> Unit,
+    cameraSessionId: Int,
     canFlipCamera: Boolean,
     requestFlipCamera: () -> Unit,
     detectedPose: Boolean,
     defaultZoomOptions: List<Float>,
+    zoomRange: ClosedFloatingPointRange<Float>,
     zoomLevel: () -> Float,
-    onChangeZoomLevel: (Float) -> Unit,
+    onChangeZoomLevel: (zoomLevel: Float) -> Unit,
     requestCaptureImage: () -> Unit,
     modifier: Modifier = Modifier,
     foldingFeature: FoldingFeature? = null,
     shouldShowRearCameraFeature: () -> Boolean = { false },
     toggleRearCameraFeature: () -> Unit = {},
     isRearCameraEnabled: Boolean = false,
 ) {
+  val scope = rememberCoroutineScope()
+    val zoomState = remember(cameraSessionId) {
+      ZoomState(
+        initialZoomLevel = zoomLevel(),
+        onChangeZoomLevel = onChangeZoomLevel,
+        zoomRange = zoomRange,
+      )
+    }
     // Delegate the layout to the stateless version
     StatelessCameraPreviewContent(
         viewfinder = { viewfinderModifier ->
@@ -309,8 +321,7 @@ private fun CameraPreviewContent(
                 surfaceRequest = surfaceRequest,
                 autofocusUiState = autofocusUiState,
                 tapToFocus = tapToFocus,
-                zoomLevel = zoomLevel,
-                onChangeZoomLevel = onChangeZoomLevel,
+                onScaleZoom = { scope.launch { zoomState.scaleZoom(it) }},
                 modifier = viewfinderModifier.onSizeChanged { size -> // Apply modifier from slot
                     if (size.height > 0) {
                         aspectRatio = calculateCorrectAspectRatio(size.height, size.width, aspectRatio)
@@ -322,9 +333,9 @@ private fun CameraPreviewContent(
         canFlipCamera = canFlipCamera,
         requestFlipCamera = requestFlipCamera,
         detectedPose = detectedPose,
-        defaultZoomOptions = defaultZoomOptions,
         zoomLevel = zoomLevel,
-        onChangeZoomLevel = onChangeZoomLevel,
+        defaultZoomOptions = defaultZoomOptions,
+        onAnimateZoom = { scope.launch { zoomState.animatedZoom(it) } },
         requestCaptureImage = requestCaptureImage,
         foldingFeature = foldingFeature,
         shouldShowRearCameraFeature = shouldShowRearCameraFeature,

feature/camera/src/main/java/com/android/developers/androidify/camera/CameraViewModel.kt

@@ -148,7 +148,7 @@ class CameraViewModel
                         processCameraProvider.runWith(cameraType, cameraUseCaseGroup) { camera ->
                             cameraControl = camera.cameraControl
                             cameraInfo = camera.cameraInfo
-
+                            _uiState.update { it.copy(cameraSessionId = it.cameraSessionId + 1) }
                             // Suspend on zoom updates
                             camera.cameraInfo.zoomState.asFlow().collectLatest { zoomState ->
                                 _uiState.update {
@@ -342,6 +342,7 @@ class CameraViewModel
  */
 data class CameraUiState(
     val surfaceRequest: SurfaceRequest? = null,
+    val cameraSessionId: Int = 0,
     val imageUri: Uri? = null,
     val detectedPose: Boolean = false,
     val zoomMaxRatio: Float = 1f,

feature/camera/src/main/java/com/android/developers/androidify/camera/CameraViewfinder.kt

@@ -47,16 +47,14 @@ private val TAP_TO_FOCUS_INDICATOR_SIZE = 48.dp
 
 @Composable
 internal fun CameraViewfinder(
-    surfaceRequest: SurfaceRequest,
-    autofocusUiState: AutofocusUiState,
-    tapToFocus: (tapCoords: Offset) -> Unit,
-    zoomLevel: () -> Float,
-    onChangeZoomLevel: (zoomLevel: Float) -> Unit,
-    modifier: Modifier = Modifier,
+  surfaceRequest: SurfaceRequest,
+  autofocusUiState: AutofocusUiState,
+  tapToFocus: (tapCoords: Offset) -> Unit,
+  onScaleZoom: (zoomScaleFactor: Float) -> Unit,
+  modifier: Modifier = Modifier,
 ) {
+    val onScaleCurrentZoom by rememberUpdatedState(onScaleZoom)
     val currentTapToFocus by rememberUpdatedState(tapToFocus)
-    val currentOnChangeZoomLevel by rememberUpdatedState(onChangeZoomLevel)
-
     val coordinateTransformer = remember { MutableCoordinateTransformer() }
     CameraXViewfinder(
         surfaceRequest = surfaceRequest,
@@ -72,7 +70,7 @@ internal fun CameraViewfinder(
             .transformable(
                 rememberTransformableState(
                     onTransformation = { zoomChange, _, _ ->
-                        currentOnChangeZoomLevel(zoomChange * zoomLevel())
+                        onScaleCurrentZoom(zoomChange)
                     },
                 ),
             ),

feature/camera/src/main/java/com/android/developers/androidify/camera/CameraZoomToolbar.kt

@@ -46,7 +46,7 @@ import kotlin.math.roundToInt
 internal fun ZoomToolbar(
     defaultZoomOptions: List<Float>,
     zoomLevel: () -> Float,
-    onZoomLevelChanged: (Float) -> Unit,
+    onZoomLevelSelected: (Float) -> Unit,
     modifier: Modifier = Modifier,
 ) {
     // Only render the zoom toolbar when there's exactly two options
@@ -87,7 +87,7 @@ internal fun ZoomToolbar(
     ) {
         ToggleButton(
             checked = selectedOptionIndex == 0,
-            onCheckedChange = { onZoomLevelChanged(defaultZoomOptions[0]) },
+            onCheckedChange = { onZoomLevelSelected(defaultZoomOptions[0]) },
             shapes = ButtonGroupDefaults.connectedLeadingButtonShapes(),
             colors = ToggleButtonDefaults.toggleButtonColors(),
             modifier = Modifier,
@@ -98,7 +98,7 @@ internal fun ZoomToolbar(
         }
         ToggleButton(
             checked = selectedOptionIndex == 1,
-            onCheckedChange = { onZoomLevelChanged(defaultZoomOptions[1]) },
+            onCheckedChange = { onZoomLevelSelected(defaultZoomOptions[1]) },
             shapes = ButtonGroupDefaults.connectedTrailingButtonShapes(),
             colors = ToggleButtonDefaults.toggleButtonColors(),
             modifier = Modifier,
@@ -120,24 +120,18 @@ private fun ZoomToolbarPreview() {
             ZoomToolbar(
                 defaultZoomOptions = listOf(0.6f, 1f),
                 zoomLevel = { zoomLevel },
-                onZoomLevelChanged = {
-                    zoomLevel = it
-                },
+                onZoomLevelSelected = { zoomLevel = it },
             )
             ZoomToolbar(
                 defaultZoomOptions = listOf(1f, 2f),
                 zoomLevel = { zoomLevel },
-                onZoomLevelChanged = {
-                    zoomLevel = it
-                },
+                onZoomLevelSelected = { zoomLevel = it },
             )
             // Doesn't render
             ZoomToolbar(
                 defaultZoomOptions = listOf(1f),
                 zoomLevel = { zoomLevel },
-                onZoomLevelChanged = {
-                    zoomLevel = it
-                },
+                onZoomLevelSelected = { zoomLevel = it },
             )
             Row {
                 Button(onClick = { zoomLevel -= 0.1f }) {