feat(scanner): migrate from drag-to-zoom to pinch-to-zoom

apps/flipcash/features/scanner/src/main/kotlin/com/flipcash/app/scanner/internal/Scanner.kt

@@ -6,6 +6,7 @@ import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableFloatStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
@@ -59,6 +60,9 @@ internal fun Scanner() {
 
     val vibrator = LocalVibrator.current
 
+    var isPinching by remember { mutableStateOf(false) }
+    var zoomRatio by remember { mutableFloatStateOf(1f) }
+
     LaunchedEffect(biometricsState, previewing) {
         if (previewing == true) {
             focusManager.clearFocus()
@@ -74,6 +78,8 @@ internal fun Scanner() {
     @SuppressLint("LocalContextGetResourceValueCall")
     BillContainer(
         isPaused = isPaused,
+        isPinching = isPinching,
+        zoomRatio = zoomRatio,
         onAction = {
             when (it) {
                 ScannerDecorItem.Give -> {
@@ -95,7 +101,10 @@ internal fun Scanner() {
             CodeScanner(
                 scanningEnabled = previewing == true,
                 cameraGesturesEnabled = true,
-                invertedDragZoomEnabled = true,
+                onPinchStateChanged = { pinching, zoom ->
+                    isPinching = pinching
+                    zoomRatio = zoom
+                },
                 onPreviewStateChanged = {
                     cameraAvailable = true
                     previewing = it

apps/flipcash/features/scanner/src/main/kotlin/com/flipcash/app/scanner/internal/bills/BillContainerView.kt

@@ -67,6 +67,8 @@ import kotlinx.coroutines.delay
 internal fun BillContainer(
     modifier: Modifier = Modifier,
     isPaused: Boolean,
+    isPinching: Boolean = false,
+    zoomRatio: Float = 1f,
     scannerView: @Composable () -> Unit,
     onAction: (ScannerDecorItem) -> Unit
 ) {
@@ -199,6 +201,8 @@ internal fun BillContainer(
                 state = updatedState,
                 billState = updatedBillState,
                 isPaused = isPaused,
+                isPinching = isPinching,
+                zoomRatio = zoomRatio,
                 onAction = onAction
             )
         }

apps/flipcash/features/scanner/src/main/kotlin/com/flipcash/app/scanner/internal/ui/components/DecorView.kt

@@ -13,6 +13,7 @@ import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.WindowInsets
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.navigationBars
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
@@ -21,6 +22,7 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.layout.windowInsetsPadding
 import androidx.compose.foundation.layout.wrapContentSize
 import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.Icon
 import androidx.compose.material.Text
 import androidx.compose.runtime.Composable
@@ -35,7 +37,9 @@ import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.flipcash.app.bill.customization.LocalBillPlaygroundController
 import com.flipcash.app.core.bill.BillState
@@ -44,6 +48,7 @@ import com.flipcash.app.session.SessionState
 import com.flipcash.features.scanner.R
 import com.getcode.theme.CodeTheme
 import com.getcode.theme.xxl
+import com.getcode.ui.components.Pill
 import com.getcode.ui.core.rememberedClickable
 import com.getcode.ui.core.unboundedClickable
 import com.getcode.utils.network.LocalNetworkObserver
@@ -53,6 +58,8 @@ internal fun DecorView(
     state: SessionState,
     billState: BillState,
     isPaused: Boolean,
+    isPinching: Boolean = false,
+    zoomRatio: Float = 1f,
     modifier: Modifier = Modifier,
     onAction: (ScannerDecorItem) -> Unit,
 ) {
@@ -111,6 +118,29 @@ internal fun DecorView(
                 )
             }
 
+            AnimatedVisibility(
+                modifier = Modifier
+                    .align(Alignment.TopCenter)
+                    .statusBarsPadding()
+                    .padding(top = CodeTheme.dimens.grid.x9),
+                visible = isPinching,
+                enter = fadeIn(tween(150)),
+                exit = fadeOut(tween(250)),
+            ) {
+                Box(
+                    modifier = Modifier.fillMaxSize(),
+                    contentAlignment = Alignment.TopCenter,
+                ) {
+                    Pill(
+                        text = "${"%.1f".format(zoomRatio)}x",
+                        textStyle = CodeTheme.typography.textSmall.copy(
+                            fontWeight = FontWeight.Bold
+                        ),
+                        shape = CodeTheme.shapes.xxl,
+                    )
+                }
+            }
+
             Column(modifier = Modifier.align(Alignment.BottomCenter)) {
                 val networkState by LocalNetworkObserver.current.state.collectAsState()
 

ui/scanner/src/main/kotlin/com/getcode/ui/scanner/CodeScanner.kt

@@ -11,24 +11,24 @@ import androidx.camera.core.Preview
 import androidx.camera.lifecycle.ProcessCameraProvider
 import androidx.camera.view.PreviewView
 import androidx.compose.animation.AnimatedVisibility
-import androidx.compose.runtime.DisposableEffect
 import androidx.compose.animation.core.tween
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableFloatStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.geometry.Offset
 import androidx.compose.ui.platform.LocalContext
-import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.viewinterop.AndroidView
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.LifecycleOwner
@@ -59,8 +59,8 @@ import java.util.concurrent.Executors
 fun CodeScanner(
     scanningEnabled: Boolean,
     cameraGesturesEnabled: Boolean,
-    invertedDragZoomEnabled: Boolean,
     modifier: Modifier = Modifier,
+    onPinchStateChanged: (Boolean, Float) -> Unit,
     onPreviewStateChanged: (Boolean) -> Unit,
     onCodeScanned: (CodeScanResult) -> Unit,
     onError: (Throwable) -> Unit = { },
@@ -98,6 +98,8 @@ fun CodeScanner(
     var camera by remember { mutableStateOf<Camera?>(null) }
     var autoFocusPoint by remember { mutableStateOf(Offset.Unspecified) }
     var gestureController by remember { mutableStateOf<CameraGestureController?>(null) }
+    var isPinching by remember { mutableStateOf(false) }
+    var zoomRatio by remember { mutableFloatStateOf(1f) }
 
     val codeAnalyzer = rememberMultiCodeAnalyzer(
         onCodeScanned = onCodeScanned,
@@ -164,14 +166,14 @@ fun CodeScanner(
         }
     }
 
-    LaunchedEffect(camera, cameraGesturesEnabled, invertedDragZoomEnabled) {
+    LaunchedEffect(camera, cameraGesturesEnabled) {
         camera?.let {
             gestureController = CameraGestureController(
                 context = context,
                 cameraControl = it.cameraControl,
                 cameraInfo = it.cameraInfo,
                 gesturesEnabled = cameraGesturesEnabled,
-                invertedDragEnabled = invertedDragZoomEnabled
+                onPinchStateChanged = onPinchStateChanged,
             ) { touchedAt ->
                 autoFocusPoint = touchedAt
                 previewView.meteringPointFactory.createPoint(touchedAt.x, touchedAt.y)
@@ -281,4 +283,4 @@ suspend fun bindWithRetry(
     throw NoCamerasAvailableException()
 }
 
-class NoCamerasAvailableException: Throwable()
+class NoCamerasAvailableException : Throwable()

ui/scanner/src/main/kotlin/com/getcode/ui/scanner/internal/CameraGestureController.kt

@@ -11,23 +11,24 @@ import androidx.camera.core.CameraInfo
 import androidx.camera.core.FocusMeteringAction
 import androidx.camera.core.MeteringPoint
 import androidx.compose.ui.geometry.Offset
-import com.getcode.ui.utils.AnimationUtils
 import java.util.concurrent.TimeUnit
+import kotlin.math.pow
 
 internal class CameraGestureController(
     context: Context,
-    invertedDragEnabled: Boolean,
     private val gesturesEnabled: Boolean,
     private val cameraControl: CameraControl,
     private val cameraInfo: CameraInfo,
+    private val onPinchStateChanged: (isPinching: Boolean, zoomRatio: Float) -> Unit = { _, _ -> },
     onTap: (Offset) -> MeteringPoint,
 ) {
     private val handler = Handler(Looper.getMainLooper())
-    private var shouldIgnoreScroll = false
-    private var resetIgnore: Runnable? = null
     private var initialZoomRatio = 0f
     private var initialZoomLevel = -1f
-    private var accumulatedDelta = 0f
+    private var gestureZoomFactor = 1f
+    private var cumulativeScale = 1f
+    private var appliedZoom = 1f
+    private var isPinching = false
 
     private val maxZoom: Float
         get() = maxZoomOrNull ?: 1f
@@ -48,40 +49,40 @@ internal class CameraGestureController(
         context,
         object : ScaleGestureDetector.SimpleOnScaleGestureListener() {
             override fun onScaleBegin(detector: ScaleGestureDetector): Boolean {
-                shouldIgnoreScroll = true
-                resetIgnore?.let { handler.removeCallbacks(it) }
+                isPinching = true
+                gestureZoomFactor = currentZoom
+                appliedZoom = currentZoom
+                cumulativeScale = 1f
+                onPinchStateChanged(true, currentZoom)
                 return true
             }
 
             override fun onScale(detector: ScaleGestureDetector): Boolean {
-                val delta = detector.scaleFactor
-                val newZoomRatio = currentZoom * delta
-
-                // Clamp the new zoom ratio between the minimum and maximum zoom ratio
-                val clampedZoomRatio = newZoomRatio.coerceIn(
+                cumulativeScale *= detector.scaleFactor
+                val amplified = cumulativeScale.toDouble().pow(1.3).toFloat()
+                val targetZoom = (gestureZoomFactor * amplified).coerceIn(
                     minZoom,
-                    maxZoomOrNull ?: currentZoom
+                    minOf(maxZoom, 20f)
                 )
-
-                // Apply the zoom to the camera control
-                cameraControl.setZoomRatio(clampedZoomRatio)
+                // Lerp toward target to smooth lens-switch transitions
+                appliedZoom += (targetZoom - appliedZoom) * 0.4f
+                cameraControl.setZoomRatio(appliedZoom)
+                onPinchStateChanged(true, appliedZoom)
                 return true
             }
 
             override fun onScaleEnd(detector: ScaleGestureDetector) {
                 initialZoomRatio = currentZoom
-                resetIgnore = Runnable { shouldIgnoreScroll = false }
-                resetIgnore?.let { handler.postDelayed(it, 500) }
+                cumulativeScale = 1f
             }
         })
 
-    // Gesture detector for tap and drag-to-zoom
+    // Gesture detector for tap-to-focus
     private val gestureDetector = GestureDetector(
         context,
         object : GestureDetector.OnGestureListener {
             override fun onDown(e: MotionEvent): Boolean {
                 initialZoomRatio = currentZoom
-                accumulatedDelta = 0f
                 return true
             }
 
@@ -100,27 +101,7 @@ internal class CameraGestureController(
                 e2: MotionEvent,
                 distanceX: Float,
                 distanceY: Float
-            ): Boolean {
-                if (!shouldIgnoreScroll) {
-                    accumulatedDelta = if (invertedDragEnabled) {
-                        accumulatedDelta + distanceY * 0.5f
-                    } else {
-                        accumulatedDelta - distanceY * 0.5f
-                    }
-
-                    val zoomDelta = AnimationUtils.ease(
-                        value = accumulatedDelta,
-                        fromRange = 0f..250f,
-                        toRange = 0f..10f,
-                        easeIn = true,
-                        easeOut = false
-                    )
-
-                    val newZoom = (initialZoomRatio + zoomDelta).coerceIn(minZoom, maxZoom)
-                    cameraControl.setZoomRatio(newZoom)
-                }
-                return true
-            }
+            ): Boolean = false
 
             override fun onShowPress(e: MotionEvent) {}
             override fun onLongPress(e: MotionEvent) {}
@@ -129,9 +110,7 @@ internal class CameraGestureController(
                 e2: MotionEvent,
                 velocityX: Float,
                 velocityY: Float
-            ): Boolean {
-                return false
-            }
+            ): Boolean = false
         }
     )
 
@@ -145,8 +124,12 @@ internal class CameraGestureController(
             gestureDetector.onTouchEvent(event)
 
             if (event.action == MotionEvent.ACTION_UP) {
-                animateZoomReset(cameraInfo, cameraControl)
-                initialZoomRatio = currentZoom
+                if (isPinching) {
+                    onPinchStateChanged(false, currentZoom)
+                    animateZoomReset(cameraInfo, cameraControl)
+                    initialZoomRatio = currentZoom
+                    isPinching = false
+                }
             }
         }
     }