Add bottom bar gesture exclusion, dual image save, thumbnail preview, and gallery picker

- Increase bottom padding and add systemGestureExclusion to prevent
  accidental navigation gestures from the capture controls
- Save both original and processed images with shared timestamps
  (TILTSHIFT_* and ORIGINAL_*) via new saveBitmapPair() pipeline
- Show animated thumbnail of last captured photo at bottom-right;
  tap opens the image in the default photo viewer
- Add gallery picker button to process existing photos through the
  tilt-shift pipeline with full EXIF rotation support

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/src/main/java/no/naiv/tiltshift/camera/ImageCaptureHandler.kt

@@ -5,12 +5,15 @@ import android.graphics.Bitmap
 import android.graphics.BitmapFactory
 import android.graphics.Matrix
 import android.location.Location
+import android.net.Uri
 import android.util.Log
 import androidx.camera.core.ImageCapture
 import androidx.camera.core.ImageCaptureException
 import androidx.camera.core.ImageProxy
 import androidx.exifinterface.media.ExifInterface
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.suspendCancellableCoroutine
+import kotlinx.coroutines.withContext
 import no.naiv.tiltshift.effect.BlurMode
 import no.naiv.tiltshift.effect.BlurParameters
 import no.naiv.tiltshift.storage.PhotoSaver
@@ -38,7 +41,10 @@ class ImageCaptureHandler(
      * camera callback (synchronous CPU work) and consumed afterwards
      * in the caller's coroutine context.
      */
-    private class ProcessedCapture(val bitmap: Bitmap)
+    private class ProcessedCapture(
+        val originalBitmap: Bitmap,
+        val processedBitmap: Bitmap
+    )
 
     /**
      * Captures a photo and applies the tilt-shift effect.
@@ -80,10 +86,11 @@ class ImageCaptureHandler(
                             currentBitmap = rotateBitmap(currentBitmap, imageRotation, isFrontCamera)
 
                             val processedBitmap = applyTiltShiftEffect(currentBitmap, blurParams)
-                            currentBitmap.recycle()
+                            // Keep originalBitmap alive — both are recycled after saving
+                            val original = currentBitmap
                             currentBitmap = null
 
-                            continuation.resume(ProcessedCapture(processedBitmap))
+                            continuation.resume(ProcessedCapture(original, processedBitmap))
                         } catch (e: Exception) {
                             Log.e(TAG, "Image processing failed", e)
                             currentBitmap?.recycle()
@@ -104,22 +111,46 @@ class ImageCaptureHandler(
             )
         }
 
-        // Phase 2: save to disk in the caller's coroutine context (suspend-safe)
+        // Phase 2: save both original and processed to disk (suspend-safe)
         if (captureResult is ProcessedCapture) {
             return try {
-                photoSaver.saveBitmap(
-                    captureResult.bitmap,
-                    ExifInterface.ORIENTATION_NORMAL,
-                    location
+                val thumbnail = createThumbnail(captureResult.processedBitmap)
+                val result = photoSaver.saveBitmapPair(
+                    original = captureResult.originalBitmap,
+                    processed = captureResult.processedBitmap,
+                    orientation = ExifInterface.ORIENTATION_NORMAL,
+                    location = location
                 )
+                if (result is SaveResult.Success) {
+                    result.copy(thumbnail = thumbnail)
+                } else {
+                    thumbnail?.recycle()
+                    result
+                }
             } finally {
-                captureResult.bitmap.recycle()
+                captureResult.originalBitmap.recycle()
+                captureResult.processedBitmap.recycle()
             }
         }
 
         return captureResult as SaveResult
     }
 
+    /**
+     * Creates a small thumbnail copy of a bitmap for in-app preview.
+     */
+    private fun createThumbnail(source: Bitmap, maxSize: Int = 160): Bitmap? {
+        return try {
+            val scale = maxSize.toFloat() / maxOf(source.width, source.height)
+            val width = (source.width * scale).toInt()
+            val height = (source.height * scale).toInt()
+            Bitmap.createScaledBitmap(source, width, height, true)
+        } catch (e: Exception) {
+            Log.w(TAG, "Failed to create thumbnail", e)
+            null
+        }
+    }
+
     /**
      * Rotates a bitmap to the correct orientation.
      */
@@ -158,6 +189,107 @@ class ImageCaptureHandler(
         return BitmapFactory.decodeByteArray(bytes, 0, bytes.size)
     }
 
+    /**
+     * Processes an existing image from the gallery through the tilt-shift pipeline.
+     * Loads the image, applies EXIF rotation, processes the effect, and saves both versions.
+     */
+    suspend fun processExistingImage(
+        imageUri: Uri,
+        blurParams: BlurParameters,
+        location: Location?
+    ): SaveResult = withContext(Dispatchers.IO) {
+        var originalBitmap: Bitmap? = null
+        var processedBitmap: Bitmap? = null
+        try {
+            originalBitmap = loadBitmapFromUri(imageUri)
+                ?: return@withContext SaveResult.Error("Failed to load image")
+
+            originalBitmap = applyExifRotation(imageUri, originalBitmap)
+
+            processedBitmap = applyTiltShiftEffect(originalBitmap, blurParams)
+
+            val thumbnail = createThumbnail(processedBitmap)
+
+            val result = photoSaver.saveBitmapPair(
+                original = originalBitmap,
+                processed = processedBitmap,
+                orientation = ExifInterface.ORIENTATION_NORMAL,
+                location = location
+            )
+
+            if (result is SaveResult.Success) {
+                result.copy(thumbnail = thumbnail)
+            } else {
+                thumbnail?.recycle()
+                result
+            }
+        } catch (e: Exception) {
+            Log.e(TAG, "Gallery image processing failed", e)
+            SaveResult.Error("Processing failed: ${e.message}", e)
+        } finally {
+            originalBitmap?.recycle()
+            processedBitmap?.recycle()
+        }
+    }
+
+    /**
+     * Loads a bitmap from a content URI.
+     */
+    private fun loadBitmapFromUri(uri: Uri): Bitmap? {
+        return try {
+            context.contentResolver.openInputStream(uri)?.use { stream ->
+                BitmapFactory.decodeStream(stream)
+            }
+        } catch (e: Exception) {
+            Log.e(TAG, "Failed to load bitmap from URI", e)
+            null
+        }
+    }
+
+    /**
+     * Reads EXIF orientation from a content URI and applies the
+     * required rotation/flip to the bitmap.
+     */
+    private fun applyExifRotation(uri: Uri, bitmap: Bitmap): Bitmap {
+        val orientation = try {
+            context.contentResolver.openInputStream(uri)?.use { stream ->
+                ExifInterface(stream).getAttributeInt(
+                    ExifInterface.TAG_ORIENTATION,
+                    ExifInterface.ORIENTATION_NORMAL
+                )
+            } ?: ExifInterface.ORIENTATION_NORMAL
+        } catch (e: Exception) {
+            Log.w(TAG, "Failed to read EXIF orientation", e)
+            ExifInterface.ORIENTATION_NORMAL
+        }
+
+        val matrix = Matrix()
+        when (orientation) {
+            ExifInterface.ORIENTATION_ROTATE_90 -> matrix.postRotate(90f)
+            ExifInterface.ORIENTATION_ROTATE_180 -> matrix.postRotate(180f)
+            ExifInterface.ORIENTATION_ROTATE_270 -> matrix.postRotate(270f)
+            ExifInterface.ORIENTATION_FLIP_HORIZONTAL -> matrix.postScale(-1f, 1f)
+            ExifInterface.ORIENTATION_FLIP_VERTICAL -> matrix.postScale(1f, -1f)
+            ExifInterface.ORIENTATION_TRANSPOSE -> {
+                matrix.postRotate(90f)
+                matrix.postScale(-1f, 1f)
+            }
+            ExifInterface.ORIENTATION_TRANSVERSE -> {
+                matrix.postRotate(270f)
+                matrix.postScale(-1f, 1f)
+            }
+            else -> return bitmap
+        }
+
+        val rotated = Bitmap.createBitmap(
+            bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true
+        )
+        if (rotated != bitmap) {
+            bitmap.recycle()
+        }
+        return rotated
+    }
+
     /**
      * Applies tilt-shift blur effect to a bitmap.
      * Supports both linear and radial modes.

app/src/main/java/no/naiv/tiltshift/storage/PhotoSaver.kt

@@ -21,7 +21,12 @@ import java.util.Locale
  * Result of a photo save operation.
  */
 sealed class SaveResult {
-    data class Success(val uri: Uri, val path: String) : SaveResult()
+    data class Success(
+        val uri: Uri,
+        val path: String,
+        val originalUri: Uri? = null,
+        val thumbnail: android.graphics.Bitmap? = null
+    ) : SaveResult()
     data class Error(val message: String, val exception: Exception? = null) : SaveResult()
 }
 
@@ -44,10 +49,44 @@ class PhotoSaver(private val context: Context) {
         orientation: Int,
         location: Location?
     ): SaveResult = withContext(Dispatchers.IO) {
-        try {
         val fileName = "TILTSHIFT_${fileNameFormat.format(Date())}.jpg"
+        saveSingleBitmap(fileName, bitmap, orientation, location)
+    }
 
-            // Create content values for MediaStore
+    /**
+     * Saves both original and processed bitmaps to the gallery.
+     * Uses a shared timestamp so paired files sort together.
+     * Returns the processed image's URI as the primary result.
+     */
+    suspend fun saveBitmapPair(
+        original: Bitmap,
+        processed: Bitmap,
+        orientation: Int,
+        location: Location?
+    ): SaveResult = withContext(Dispatchers.IO) {
+        val timestamp = fileNameFormat.format(Date())
+        val processedFileName = "TILTSHIFT_${timestamp}.jpg"
+        val originalFileName = "ORIGINAL_${timestamp}.jpg"
+
+        val processedResult = saveSingleBitmap(processedFileName, processed, orientation, location)
+        if (processedResult is SaveResult.Error) return@withContext processedResult
+
+        val originalResult = saveSingleBitmap(originalFileName, original, orientation, location)
+        val originalUri = (originalResult as? SaveResult.Success)?.uri
+
+        (processedResult as SaveResult.Success).copy(originalUri = originalUri)
+    }
+
+    /**
+     * Core save logic: writes a single bitmap to MediaStore with EXIF data.
+     */
+    private fun saveSingleBitmap(
+        fileName: String,
+        bitmap: Bitmap,
+        orientation: Int,
+        location: Location?
+    ): SaveResult {
+        return try {
             val contentValues = ContentValues().apply {
                 put(MediaStore.Images.Media.DISPLAY_NAME, fileName)
                 put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg")
@@ -57,29 +96,23 @@ class PhotoSaver(private val context: Context) {
                 put(MediaStore.Images.Media.IS_PENDING, 1)
             }
 
-            // Insert into MediaStore
             val contentResolver = context.contentResolver
             val uri = contentResolver.insert(
                 MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                 contentValues
-            ) ?: return@withContext SaveResult.Error("Failed to create MediaStore entry")
+            ) ?: return SaveResult.Error("Failed to create MediaStore entry")
 
-            // Write bitmap to output stream
             contentResolver.openOutputStream(uri)?.use { outputStream ->
                 bitmap.compress(Bitmap.CompressFormat.JPEG, 95, outputStream)
-            } ?: return@withContext SaveResult.Error("Failed to open output stream")
+            } ?: return SaveResult.Error("Failed to open output stream")
 
-            // Write EXIF data
             writeExifToUri(uri, orientation, location)
 
-            // Mark as complete
             contentValues.clear()
             contentValues.put(MediaStore.Images.Media.IS_PENDING, 0)
             contentResolver.update(uri, contentValues, null, null)
 
-            // Get the file path for display
             val path = getPathFromUri(uri)
-
             SaveResult.Success(uri, path)
         } catch (e: Exception) {
             SaveResult.Error("Failed to save photo: ${e.message}", e)

app/src/main/java/no/naiv/tiltshift/ui/CameraScreen.kt

@@ -1,15 +1,20 @@
 package no.naiv.tiltshift.ui
 
+import android.content.Intent
+import android.graphics.Bitmap
 import android.graphics.SurfaceTexture
 import android.location.Location
+import android.net.Uri
 import android.opengl.GLSurfaceView
 import android.view.Surface
 import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
+import androidx.compose.animation.scaleIn
 import androidx.compose.foundation.background
 import androidx.compose.foundation.border
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.systemGestureExclusion
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -25,10 +30,14 @@ import androidx.compose.foundation.layout.statusBarsPadding
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.PickVisualMediaRequest
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Check
 import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.FlipCameraAndroid
+import androidx.compose.material.icons.filled.PhotoLibrary
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.Slider
@@ -46,8 +55,11 @@ import androidx.compose.runtime.rememberUpdatedState
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.foundation.Image
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.platform.LocalContext
 import androidx.lifecycle.compose.LocalLifecycleOwner
 import androidx.compose.ui.unit.dp
@@ -97,9 +109,47 @@ fun CameraScreen(
     var showSaveError by remember { mutableStateOf<String?>(null) }
     var showControls by remember { mutableStateOf(false) }
 
+    // Thumbnail state for last captured photo
+    var lastSavedUri by remember { mutableStateOf<Uri?>(null) }
+    var lastThumbnailBitmap by remember { mutableStateOf<Bitmap?>(null) }
+
     var currentRotation by remember { mutableStateOf(Surface.ROTATION_0) }
     var currentLocation by remember { mutableStateOf<Location?>(null) }
 
+    // Gallery picker: process a selected image through the tilt-shift pipeline
+    val galleryLauncher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.PickVisualMedia()
+    ) { uri ->
+        if (uri != null && !isCapturing) {
+            isCapturing = true
+            scope.launch {
+                val result = captureHandler.processExistingImage(
+                    imageUri = uri,
+                    blurParams = blurParams,
+                    location = currentLocation
+                )
+                when (result) {
+                    is SaveResult.Success -> {
+                        haptics.success()
+                        lastThumbnailBitmap?.recycle()
+                        lastThumbnailBitmap = result.thumbnail
+                        lastSavedUri = result.uri
+                        showSaveSuccess = true
+                        delay(1500)
+                        showSaveSuccess = false
+                    }
+                    is SaveResult.Error -> {
+                        haptics.error()
+                        showSaveError = result.message
+                        delay(2000)
+                        showSaveError = null
+                    }
+                }
+                isCapturing = false
+            }
+        }
+    }
+
     val zoomRatio by cameraManager.zoomRatio.collectAsState()
     val minZoom by cameraManager.minZoomRatio.collectAsState()
     val maxZoom by cameraManager.maxZoomRatio.collectAsState()
@@ -154,6 +204,7 @@ fun CameraScreen(
         onDispose {
             cameraManager.release()
             renderer?.release()
+            lastThumbnailBitmap?.recycle()
         }
     }
 
@@ -281,7 +332,8 @@ fun CameraScreen(
             modifier = Modifier
                 .align(Alignment.BottomCenter)
                 .navigationBarsPadding()
-                .padding(bottom = 24.dp),
+                .padding(bottom = 48.dp)
+                .systemGestureExclusion(),
             horizontalAlignment = Alignment.CenterHorizontally
         ) {
             // Zoom presets (only show for back camera)
@@ -299,6 +351,31 @@ fun CameraScreen(
                 Spacer(modifier = Modifier.height(24.dp))
             }
 
+            // Gallery button | Capture button | Spacer for symmetry
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.spacedBy(24.dp)
+            ) {
+                // Gallery picker button
+                IconButton(
+                    onClick = {
+                        if (!isCapturing) {
+                            galleryLauncher.launch(
+                                PickVisualMediaRequest(ActivityResultContracts.PickVisualMedia.ImageOnly)
+                            )
+                        }
+                    },
+                    enabled = !isCapturing,
+                    modifier = Modifier.size(52.dp)
+                ) {
+                    Icon(
+                        imageVector = Icons.Default.PhotoLibrary,
+                        contentDescription = "Pick from gallery",
+                        tint = Color.White,
+                        modifier = Modifier.size(28.dp)
+                    )
+                }
+
                 // Capture button
                 CaptureButton(
                     isCapturing = isCapturing,
@@ -322,6 +399,9 @@ fun CameraScreen(
                                     when (result) {
                                         is SaveResult.Success -> {
                                             haptics.success()
+                                            lastThumbnailBitmap?.recycle()
+                                            lastThumbnailBitmap = result.thumbnail
+                                            lastSavedUri = result.uri
                                             showSaveSuccess = true
                                             delay(1500)
                                             showSaveSuccess = false
@@ -339,7 +419,29 @@ fun CameraScreen(
                         }
                     }
                 )
+
+                // Spacer for visual symmetry with gallery button
+                Spacer(modifier = Modifier.size(52.dp))
             }
+        }
+
+        // Last captured photo thumbnail
+        LastPhotoThumbnail(
+            thumbnail = lastThumbnailBitmap,
+            onTap = {
+                lastSavedUri?.let { uri ->
+                    val intent = Intent(Intent.ACTION_VIEW).apply {
+                        setDataAndType(uri, "image/jpeg")
+                        addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
+                    }
+                    context.startActivity(intent)
+                }
+            },
+            modifier = Modifier
+                .align(Alignment.BottomEnd)
+                .navigationBarsPadding()
+                .padding(bottom = 48.dp, end = 16.dp)
+        )
 
         // Success indicator
         AnimatedVisibility(
@@ -564,3 +666,34 @@ private fun CaptureButton(
         )
     }
 }
+
+/**
+ * Rounded thumbnail of the last captured photo.
+ * Tapping opens the image in the default photo viewer.
+ */
+@Composable
+private fun LastPhotoThumbnail(
+    thumbnail: Bitmap?,
+    onTap: () -> Unit,
+    modifier: Modifier = Modifier
+) {
+    AnimatedVisibility(
+        visible = thumbnail != null,
+        enter = fadeIn() + scaleIn(initialScale = 0.6f),
+        exit = fadeOut(),
+        modifier = modifier
+    ) {
+        thumbnail?.let { bmp ->
+            Image(
+                bitmap = bmp.asImageBitmap(),
+                contentDescription = "Last captured photo",
+                contentScale = ContentScale.Crop,
+                modifier = Modifier
+                    .size(52.dp)
+                    .clip(RoundedCornerShape(10.dp))
+                    .border(2.dp, Color.White, RoundedCornerShape(10.dp))
+                    .clickable(onClick = onTap)
+            )
+        }
+    }
+}