feat(wallpaper-store): enhance previews, EXIF handling, and shuffle

These changes add image previews and robust image handling across platforms.
Android, desktop, and TS UI now share imagePreviews data and a
persistent shuffle queue, improving ordering and previews.
EXIF orientation is applied when decoding images and rendering crops.
Manifest and rendering paths were adjusted for portrait mode.

- Introduce imagePreviews in models and UI to show per-image crop data.
- Implement EXIF orientation handling and enhanced cropping.
- Improve shuffle with persistent queue and seen-tracking.

plugins/android/src/main/java/WallpaperStore.kt

@@ -8,6 +8,9 @@ import android.graphics.Canvas
 import android.graphics.Color
 import android.graphics.Matrix
 import android.graphics.Paint
+import android.graphics.RectF
+import android.media.ExifInterface
+import android.os.Build
 import android.util.Base64
 import android.util.LruCache
 import app.tauri.plugin.JSArray
@@ -15,6 +18,7 @@ import app.tauri.plugin.JSObject
 import java.io.ByteArrayOutputStream
 import java.io.File
 import java.security.MessageDigest
+import org.json.JSONArray
 import org.json.JSONObject
 
 object WallpaperStore {
@@ -23,11 +27,14 @@ object WallpaperStore {
   private const val KEY_CURRENT_ID = "current_entry_id"
   private const val KEY_INTERVAL = "interval_minutes"
   private const val KEY_SHUFFLE_SEEN_IDS = "shuffle_seen_ids"
+  private const val KEY_SHUFFLE_QUEUE_IDS = "shuffle_queue_ids"
   private const val CROP_PREFIX = "crop_"
   private const val INVALID_PREFIX = "invalid_"
+  private const val RENDER_VERSION = 7
+  private const val THUMBNAIL_VERSION = 2
   private const val RENDER_CACHE_MAX_BYTES = 128L * 1024 * 1024
   private const val THUMBNAIL_CACHE_MAX_BYTES = 64L * 1024 * 1024
-  private const val HOME_PREVIEW_LIMIT = 12
+  private const val HOME_PREVIEW_LIMIT = 6
   private val thumbnailCache = LruCache<String, String>(48)
 
   private data class CropSettings(val mode: String = "cover", val zoom: Double = 1.0, val x: Double = 0.5, val y: Double = 0.5, val rotation: Int = 0)
@@ -93,6 +100,38 @@ object WallpaperStore {
     return legacy
   }
 
+  private fun addedAt(entry: Entry): Long = when (entry) {
+    is Entry.Local -> entry.file.name.substringBefore('-').toLongOrNull() ?: entry.file.lastModified()
+    is Entry.Immich -> entry.addedAt
+  }
+
+  private fun writeShuffleQueue(context: Context, ids: List<String>) {
+    prefs(context).edit().putString(KEY_SHUFFLE_QUEUE_IDS, JSONArray(ids).toString()).apply()
+  }
+
+  private fun shuffleOrder(context: Context, items: List<Entry>, currentId: String): Pair<MutableSet<String>, MutableList<String>> {
+    val availableIds = items.mapTo(linkedSetOf()) { it.id }
+    val preferences = prefs(context)
+    val seenIds = preferences.getStringSet(KEY_SHUFFLE_SEEN_IDS, emptySet())
+      .orEmpty().filterTo(linkedSetOf()) { it in availableIds }
+    seenIds.add(currentId)
+    if (seenIds.size >= availableIds.size && availableIds.size > 1) {
+      seenIds.clear()
+      seenIds.add(currentId)
+    }
+
+    val storedQueue = runCatching {
+      val json = JSONArray(preferences.getString(KEY_SHUFFLE_QUEUE_IDS, "[]"))
+      (0 until json.length()).map { json.getString(it) }
+    }.getOrDefault(emptyList())
+    val queue = storedQueue.filterTo(mutableListOf()) { it in availableIds && it !in seenIds }
+    val missing = availableIds.filter { it !in seenIds && it !in queue }.shuffled()
+    queue.addAll(missing)
+    preferences.edit().putStringSet(KEY_SHUFFLE_SEEN_IDS, seenIds).apply()
+    writeShuffleQueue(context, queue)
+    return seenIds to queue
+  }
+
   fun intervalMinutes(context: Context): Int {
     val preferences = prefs(context)
     return if (preferences.contains(KEY_INTERVAL)) preferences.getInt(KEY_INTERVAL, 0)
@@ -109,7 +148,7 @@ object WallpaperStore {
   fun set(context: Context, name: String, value: Boolean) {
     require(name in setOf("shuffle", "lockScreenOnly", "allowMobileData", "prefetchImmich")) { "Unbekannte Einstellung" }
     val editor = prefs(context).edit().putBoolean(name, value)
-    if (name == "shuffle") editor.remove(KEY_SHUFFLE_SEEN_IDS)
+    if (name == "shuffle") editor.remove(KEY_SHUFFLE_SEEN_IDS).remove(KEY_SHUFFLE_QUEUE_IDS)
     editor.apply()
     if (name == "prefetchImmich") {
       if (value && ImmichClient.configured(context)) ImmichPrefetchWorker.enqueue(context)
@@ -126,8 +165,15 @@ object WallpaperStore {
   fun state(context: Context, includePreviews: Boolean = true): JSObject {
     val items = entries(context)
     val index = currentIndex(context, items)
-    val previewItems = if (index < HOME_PREVIEW_LIMIT) items.take(HOME_PREVIEW_LIMIT) else listOf(items[index]) + items.take(HOME_PREVIEW_LIMIT - 1)
-    val previewIndex = if (index < HOME_PREVIEW_LIMIT) index else 0
+    val previewItems = if (items.isEmpty()) emptyList() else {
+      val current = items[index]
+      if (shuffle(context) && items.size > 1) {
+        val queue = shuffleOrder(context, items, current.id).second
+        listOf(current) + queue.take(HOME_PREVIEW_LIMIT - 1).mapNotNull { id -> items.firstOrNull { it.id == id } }
+      } else {
+        (0 until minOf(HOME_PREVIEW_LIMIT, items.size)).map { items[(index + it).mod(items.size)] }
+      }
+    }
     return JSObject().apply {
       put("imageCount", items.size)
       put("enabled", enabled(context))
@@ -136,7 +182,7 @@ object WallpaperStore {
       put("lockScreenOnly", lockOnly(context))
       put("allowMobileData", allowMobileData(context))
       put("prefetchImmich", prefetchImmich(context))
-      put("currentIndex", previewIndex)
+      put("currentIndex", 0)
       put("currentId", items.getOrNull(index)?.id ?: JSONObject.NULL)
       val ids = JSArray()
       previewItems.forEach { ids.put(it.id) }
@@ -144,20 +190,24 @@ object WallpaperStore {
       val previews = JSArray()
       if (includePreviews) previewItems.forEach { previews.put(thumbnailDataUrl(context, it.preview)) }
       put("imageUrls", previews)
+      val imagePreviews = JSArray()
+      if (includePreviews) previewItems.forEach { imagePreviews.put(galleryImage(context, it, it.id == items.getOrNull(index)?.id)) }
+      put("imagePreviews", imagePreviews)
     }
   }
 
   @Synchronized
   fun gallery(context: Context, offset: Int, limit: Int): JSObject {
     val items = entries(context)
-    val selectedIndex = currentIndex(context, items)
-    val safeOffset = offset.coerceAtLeast(0).coerceAtMost(items.size)
+    val selectedId = items.getOrNull(currentIndex(context, items))?.id
+    val galleryItems = items.sortedWith(compareByDescending<Entry> { addedAt(it) }.thenByDescending { it.id })
+    val safeOffset = offset.coerceAtLeast(0).coerceAtMost(galleryItems.size)
     val safeLimit = limit.coerceIn(1, 100)
     val page = JSArray()
-    items.drop(safeOffset).take(safeLimit).forEachIndexed { pageIndex, entry ->
-      page.put(galleryImage(context, entry, safeOffset + pageIndex == selectedIndex))
+    galleryItems.drop(safeOffset).take(safeLimit).forEach { entry ->
+      page.put(galleryImage(context, entry, entry.id == selectedId))
     }
-    return JSObject().apply { put("total", items.size); put("items", page) }
+    return JSObject().apply { put("total", galleryItems.size); put("items", page) }
   }
 
   @Synchronized
@@ -215,8 +265,16 @@ object WallpaperStore {
     val json = JSONObject().apply {
       put("mode", normalized.mode); put("zoom", normalized.zoom); put("x", normalized.x); put("y", normalized.y); put("rotation", normalized.rotation)
     }
-    prefs(context).edit().putString(cropKey(id), json.toString()).apply()
-    return galleryImage(context, entry, items.indexOf(entry) == currentIndex(context, items))
+    val selected = items.indexOf(entry) == currentIndex(context, items)
+    check(prefs(context).edit().putString(cropKey(id), json.toString()).commit()) {
+      "Bildausschnitt konnte nicht gespeichert werden"
+    }
+    if (selected) {
+      check(apply(context, id)) {
+        "Bildausschnitt wurde gespeichert, konnte aber nicht angewendet werden"
+      }
+    }
+    return galleryImage(context, entry, selected)
   }
 
   @Synchronized
@@ -288,27 +346,42 @@ object WallpaperStore {
     val metrics = context.resources.displayMetrics
     val targetWidth = metrics.widthPixels.coerceAtLeast(1)
     val targetHeight = metrics.heightPixels.coerceAtLeast(1)
-    val quarterTurn = crop.rotation == 90 || crop.rotation == 270
-    val rotatedWidth = if (quarterTurn) source.height else source.width
-    val rotatedHeight = if (quarterTurn) source.width else source.height
+    val rotated = if (crop.rotation == 0) source else Bitmap.createBitmap(
+      source,
+      0,
+      0,
+      source.width,
+      source.height,
+      Matrix().apply { setRotate(crop.rotation.toFloat()) },
+      true,
+    )
+    val rotatedWidth = rotated.width
+    val rotatedHeight = rotated.height
     val widthScale = targetWidth.toDouble() / rotatedWidth
     val heightScale = targetHeight.toDouble() / rotatedHeight
     val baseScale = if (crop.mode == "contain") minOf(widthScale, heightScale) else maxOf(widthScale, heightScale)
     val scale = (baseScale * crop.zoom).toFloat()
+    val baseWidth = rotatedWidth * baseScale
+    val baseHeight = rotatedHeight * baseScale
     val scaledWidth = rotatedWidth * scale
     val scaledHeight = rotatedHeight * scale
-    val left = ((targetWidth - scaledWidth) * crop.x).toFloat()
-    val top = ((targetHeight - scaledHeight) * crop.y).toFloat()
-    return Bitmap.createBitmap(targetWidth, targetHeight, Bitmap.Config.ARGB_8888).also { output ->
-      val canvas = Canvas(output)
-      canvas.drawColor(Color.BLACK)
-      val matrix = Matrix().apply {
-        postTranslate(-source.width / 2f, -source.height / 2f)
-        postRotate(crop.rotation.toFloat())
-        postScale(scale, scale)
-        postTranslate(left + scaledWidth / 2f, top + scaledHeight / 2f)
+    val baseLeft = (targetWidth - baseWidth) * crop.x
+    val baseTop = (targetHeight - baseHeight) * crop.y
+    val left = (targetWidth / 2.0 + (baseLeft - targetWidth / 2.0) * crop.zoom).toFloat()
+    val top = (targetHeight / 2.0 + (baseTop - targetHeight / 2.0) * crop.zoom).toFloat()
+    return try {
+      Bitmap.createBitmap(targetWidth, targetHeight, Bitmap.Config.ARGB_8888).also { output ->
+        val canvas = Canvas(output)
+        canvas.drawColor(Color.BLACK)
+        canvas.drawBitmap(
+          rotated,
+          null,
+          RectF(left, top, left + scaledWidth, top + scaledHeight),
+          Paint(Paint.ANTI_ALIAS_FLAG or Paint.FILTER_BITMAP_FLAG),
+        )
       }
-      canvas.drawBitmap(source, matrix, Paint(Paint.ANTI_ALIAS_FLAG or Paint.FILTER_BITMAP_FLAG))
+    } finally {
+      if (rotated !== source) rotated.recycle()
     }
   }
 
@@ -319,11 +392,34 @@ object WallpaperStore {
     val targetLongSide = maxOf(context.resources.displayMetrics.widthPixels, context.resources.displayMetrics.heightPixels).coerceAtLeast(1)
     var sample = 1
     while (maxOf(bounds.outWidth, bounds.outHeight) / (sample * 2) >= targetLongSide) sample *= 2
-    return BitmapFactory.decodeFile(file.absolutePath, BitmapFactory.Options().apply { inSampleSize = sample; inPreferredConfig = Bitmap.Config.ARGB_8888 })
+    val decoded = BitmapFactory.decodeFile(file.absolutePath, BitmapFactory.Options().apply { inSampleSize = sample; inPreferredConfig = Bitmap.Config.ARGB_8888 }) ?: return null
+    return applyExifOrientation(file, decoded)
+  }
+
+  private fun applyExifOrientation(file: File, bitmap: Bitmap): Bitmap {
+    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) return bitmap
+    val orientation = runCatching {
+      ExifInterface(file.absolutePath).getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL)
+    }.getOrDefault(ExifInterface.ORIENTATION_NORMAL)
+    val matrix = Matrix().apply {
+      when (orientation) {
+        ExifInterface.ORIENTATION_FLIP_HORIZONTAL -> setScale(-1f, 1f)
+        ExifInterface.ORIENTATION_ROTATE_180 -> setRotate(180f)
+        ExifInterface.ORIENTATION_FLIP_VERTICAL -> setScale(1f, -1f)
+        ExifInterface.ORIENTATION_TRANSPOSE -> { setRotate(90f); postScale(-1f, 1f) }
+        ExifInterface.ORIENTATION_ROTATE_90 -> setRotate(90f)
+        ExifInterface.ORIENTATION_TRANSVERSE -> { setRotate(-90f); postScale(-1f, 1f) }
+        ExifInterface.ORIENTATION_ROTATE_270 -> setRotate(-90f)
+      }
+    }
+    if (matrix.isIdentity) return bitmap
+    val oriented = Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true)
+    if (oriented !== bitmap) bitmap.recycle()
+    return oriented
   }
 
   private fun thumbnailDataUrl(context: Context, file: File): String {
-    val cacheKey = "${file.absolutePath}:${file.lastModified()}:${file.length()}"
+    val cacheKey = "$THUMBNAIL_VERSION:${file.absolutePath}:${file.lastModified()}:${file.length()}"
     thumbnailCache.get(cacheKey)?.let { return it }
     val cached = File(thumbnailDirectory(context), "${digest(cacheKey)}.jpg")
     if (cached.isFile) {
@@ -336,7 +432,8 @@ object WallpaperStore {
     BitmapFactory.decodeFile(file.absolutePath, bounds)
     var sample = 1
     while (bounds.outWidth / sample > 360 || bounds.outHeight / sample > 480) sample *= 2
-    val bitmap = BitmapFactory.decodeFile(file.absolutePath, BitmapFactory.Options().apply { inSampleSize = sample }) ?: return ""
+    val decoded = BitmapFactory.decodeFile(file.absolutePath, BitmapFactory.Options().apply { inSampleSize = sample }) ?: return ""
+    val bitmap = applyExifOrientation(file, decoded)
     val result = ByteArrayOutputStream().use { out ->
       bitmap.compress(Bitmap.CompressFormat.JPEG, 76, out); bitmap.recycle()
       val bytes = out.toByteArray()
@@ -348,7 +445,7 @@ object WallpaperStore {
   }
 
   private fun removeThumbnail(file: File) {
-    thumbnailCache.remove("${file.absolutePath}:${file.lastModified()}:${file.length()}")
+    thumbnailCache.remove("$THUMBNAIL_VERSION:${file.absolutePath}:${file.lastModified()}:${file.length()}")
   }
 
   private fun digest(value: String): String = MessageDigest.getInstance("SHA-256")
@@ -360,7 +457,7 @@ object WallpaperStore {
       is Entry.Local -> "${entry.file.lastModified()}:${entry.file.length()}"
       is Entry.Immich -> entry.assetId
     }
-    val key = "${entry.id}:$sourceVersion:${metrics.widthPixels}x${metrics.heightPixels}:${prefs(context).getString(cropKey(entry.id), "")}"
+    val key = "$RENDER_VERSION:${entry.id}:$sourceVersion:${metrics.widthPixels}x${metrics.heightPixels}:${prefs(context).getString(cropKey(entry.id), "")}"
     return File(renderedDirectory(context), "${digest(key)}.jpg")
   }
 
@@ -394,18 +491,15 @@ object WallpaperStore {
     if (items.isEmpty()) return false
     val previous = currentIndex(context, items)
     if (shuffle(context) && items.size > 1) {
-      val availableIds = items.mapTo(mutableSetOf()) { it.id }
-      val seenIds = prefs(context).getStringSet(KEY_SHUFFLE_SEEN_IDS, emptySet())
-        .orEmpty().filterTo(mutableSetOf()) { it in availableIds }
-      seenIds.add(items[previous].id)
-
-      var candidates = items.indices.filter { items[it].id !in seenIds }.shuffled()
-      if (candidates.isEmpty()) {
-        seenIds.clear()
-        seenIds.add(items[previous].id)
-        candidates = items.indices.filter { it != previous }.shuffled()
+      val (seenIds, queue) = shuffleOrder(context, items, items[previous].id)
+      val candidates = queue.mapNotNull { id -> items.indexOfFirst { it.id == id }.takeIf { it >= 0 } }
+      val applied = applyCandidates(context, items, candidates, automatic, seenIds)
+      if (applied) {
+        val selectedId = prefs(context).getString(KEY_CURRENT_ID, null)
+        val selectedPosition = queue.indexOf(selectedId)
+        writeShuffleQueue(context, if (selectedPosition >= 0) queue.drop(selectedPosition + 1) else queue.filter { it != selectedId })
       }
-      return applyCandidates(context, items, candidates, automatic, seenIds)
+      return applied
     }
     val candidates = (1..items.size).map { (previous + it).mod(items.size) }
     return applyCandidates(context, items, candidates, automatic)

plugins/src/desktop.rs

@@ -15,6 +15,20 @@ pub struct Wallpaper<R: Runtime>(AppHandle<R>);
 
 impl<R: Runtime> Wallpaper<R> {
     fn demo() -> WallpaperState {
+        let image_previews = ["alpine", "waterfall", "coast"]
+            .into_iter()
+            .enumerate()
+            .map(|(index, name)| GalleryImage {
+                id: format!("demo-{index}"),
+                url: format!("/wallpapers/{name}.png"),
+                selected: index == 0,
+                crop_mode: "cover".into(),
+                crop_zoom: 1.0,
+                crop_position_x: 0.5,
+                crop_position_y: 0.5,
+                crop_rotation: 0,
+            })
+            .collect();
         WallpaperState {
             image_count: 3,
             enabled: true,
@@ -31,6 +45,7 @@ impl<R: Runtime> Wallpaper<R> {
                 "/wallpapers/waterfall.png".into(),
                 "/wallpapers/coast.png".into(),
             ],
+            image_previews,
         }
     }
     pub fn get_state(&self) -> crate::Result<WallpaperState> {

plugins/src/models.rs

@@ -14,6 +14,8 @@ pub struct WallpaperState {
     pub current_id: Option<String>,
     pub image_ids: Vec<String>,
     pub image_urls: Vec<String>,
+    #[serde(default)]
+    pub image_previews: Vec<GalleryImage>,
 }
 
 #[derive(Debug, Clone, Deserialize, Serialize)]