Viewer: TIFF subsampling & tiling

android/app/src/main/kotlin/deckers/thibault/aves/channel/calls/ImageFileHandler.kt

@@ -10,6 +10,7 @@ import deckers.thibault.aves.model.provider.FieldMap
 import deckers.thibault.aves.model.provider.ImageProvider.ImageOpCallback
 import deckers.thibault.aves.model.provider.ImageProviderFactory.getProvider
 import deckers.thibault.aves.model.provider.MediaStoreImageProvider
+import deckers.thibault.aves.utils.MimeTypes
 import io.flutter.plugin.common.MethodCall
 import io.flutter.plugin.common.MethodChannel
 import io.flutter.plugin.common.MethodChannel.MethodCallHandler
@@ -95,14 +96,24 @@ class ImageFileHandler(private val activity: Activity) : MethodCallHandler {
             return
         }
 
-        regionFetcher.fetch(
+        val regionRect = Rect(x, y, x + width, y + height)
-            uri,
+        when (mimeType) {
-            mimeType,
+            MimeTypes.TIFF -> TiffRegionFetcher(activity).fetch(
-            sampleSize,
+                uri,
-            Rect(x, y, x + width, y + height),
+                sampleSize,
-            Size(imageWidth, imageHeight),
+                regionRect,
-            result,
+                page = 0,
-        )
+                result,
+            )
+            else -> regionFetcher.fetch(
+                uri,
+                mimeType,
+                sampleSize,
+                regionRect,
+                Size(imageWidth, imageHeight),
+                result,
+            )
+        }
     }
 
     private suspend fun getImageEntry(call: MethodCall, result: MethodChannel.Result) {

android/app/src/main/kotlin/deckers/thibault/aves/channel/calls/TiffRegionFetcher.kt

@@ -0,0 +1,40 @@
+package deckers.thibault.aves.channel.calls
+
+import android.content.Context
+import android.graphics.Rect
+import android.net.Uri
+import deckers.thibault.aves.utils.BitmapUtils.getBytes
+import io.flutter.plugin.common.MethodChannel
+import org.beyka.tiffbitmapfactory.DecodeArea
+import org.beyka.tiffbitmapfactory.TiffBitmapFactory
+
+class TiffRegionFetcher internal constructor(
+    private val context: Context,
+) {
+    fun fetch(
+        uri: Uri,
+        sampleSize: Int,
+        regionRect: Rect,
+        page: Int = 0,
+        result: MethodChannel.Result,
+    ) {
+        val resolver = context.contentResolver
+        try {
+            resolver.openFileDescriptor(uri, "r")?.use { descriptor ->
+                val options = TiffBitmapFactory.Options().apply {
+                    inDirectoryNumber = page
+                    inSampleSize = sampleSize
+                    inDecodeArea = DecodeArea(regionRect.left, regionRect.top, regionRect.width(), regionRect.height())
+                }
+                val bitmap = TiffBitmapFactory.decodeFileDescriptor(descriptor.fd, options)
+                if (bitmap != null) {
+                    result.success(bitmap.getBytes(canHaveAlpha = true, recycle = true))
+                } else {
+                    result.error("getRegion-tiff-null", "failed to decode region for uri=$uri page=$page regionRect=$regionRect", null)
+                }
+            }
+        } catch (e: Exception) {
+            result.error("getRegion-tiff-read-exception", "failed to read from uri=$uri page=$page regionRect=$regionRect", e.message)
+        }
+    }
+}

android/app/src/main/kotlin/deckers/thibault/aves/channel/streams/ImageByteStreamHandler.kt

@@ -95,7 +95,7 @@ class ImageByteStreamHandler(private val activity: Activity, private val argumen
     private fun streamImageByGlide(uri: Uri, mimeType: String, rotationDegrees: Int, isFlipped: Boolean) {
         val target = Glide.with(activity)
             .asBitmap()
-            .apply(options)
+            .apply(glideOptions)
             .load(uri)
             .submit()
         try {
@@ -118,7 +118,7 @@ class ImageByteStreamHandler(private val activity: Activity, private val argumen
     private fun streamVideoByGlide(uri: Uri) {
         val target = Glide.with(activity)
             .asBitmap()
-            .apply(options)
+            .apply(glideOptions)
             .load(VideoThumbnail(activity, uri))
             .submit()
         try {
@@ -135,7 +135,7 @@ class ImageByteStreamHandler(private val activity: Activity, private val argumen
         }
     }
 
-    private fun streamTiffImage(uri: Uri) {
+    private fun streamTiffImage(uri: Uri, page: Int = 0) {
         val resolver = activity.contentResolver
         try {
             var dirCount = 0
@@ -148,18 +148,17 @@ class ImageByteStreamHandler(private val activity: Activity, private val argumen
             }
 
             // TODO TLAD handle multipage TIFF
-            if (dirCount > 0) {
+            if (dirCount > page) {
-                val i = 0
                 resolver.openFileDescriptor(uri, "r")?.use { descriptor ->
                     val options = TiffBitmapFactory.Options().apply {
                         inJustDecodeBounds = false
-                        inDirectoryNumber = i
+                        inDirectoryNumber = page
                     }
                     val bitmap = TiffBitmapFactory.decodeFileDescriptor(descriptor.fd, options)
                     if (bitmap != null) {
                         success(bitmap.getBytes(canHaveAlpha = true, recycle = true))
                     } else {
-                        error("streamImage-tiff-null", "failed to get tiff image (dir=$i) from uri=$uri", null)
+                        error("streamImage-tiff-null", "failed to get tiff image (dir=$page) from uri=$uri", null)
                     }
                 }
             }
@@ -192,7 +191,7 @@ class ImageByteStreamHandler(private val activity: Activity, private val argumen
         const val bufferSize = 2 shl 17 // 256kB
 
         // request a fresh image with the highest quality format
-        val options = RequestOptions()
+        val glideOptions = RequestOptions()
             .format(DecodeFormat.PREFER_ARGB_8888)
             .diskCacheStrategy(DiskCacheStrategy.NONE)
             .skipMemoryCache(true)

lib/model/image_entry.dart

@@ -178,7 +178,7 @@ class ImageEntry {
   // Android's `BitmapRegionDecoder` documentation states that "only the JPEG and PNG formats are supported"
   // but in practice (tested on API 25, 27, 29), it successfully decodes the formats listed below,
   // and it actually fails to decode GIF, DNG and animated WEBP. Other formats were not tested.
-  bool get canTile =>
+  bool get _supportedByBitmapRegionDecoder =>
       [
         MimeTypes.heic,
         MimeTypes.heif,
@@ -196,6 +196,8 @@ class ImageEntry {
       ].contains(mimeType) &&
       !isAnimated;
 
+  bool get canTile => _supportedByBitmapRegionDecoder || mimeType == MimeTypes.tiff;
+
   bool get isRaw => MimeTypes.rawImages.contains(mimeType);
 
   bool get isVideo => mimeType.startsWith('video');