Fix cropping and rotating photos with EXIF orientation set

app/lib/widget/image_editor.dart

@@ -90,6 +90,8 @@ class _ImageEditorState extends State<ImageEditor> {
       height: k.photoLargeSize,
       a: true,
     ));
+    // no need to set shouldfixOrientation because the previews are always in
+    // the correct orientation
     _src = await ImageLoader.loadUri(
       "file://${fileInfo!.file.path}",
       _previewWidth,

plugin/android/src/main/kotlin/com/nkming/nc_photos/plugin/BitmapUtil.kt

@@ -3,7 +3,9 @@ package com.nkming.nc_photos.plugin
 import android.content.Context
 import android.graphics.Bitmap
 import android.graphics.BitmapFactory
+import android.graphics.Matrix
 import android.net.Uri
+import androidx.exifinterface.media.ExifInterface
 import java.io.InputStream
 import kotlin.contracts.ExperimentalContracts
 import kotlin.contracts.InvocationKind
@@ -91,6 +93,7 @@ interface BitmapUtil {
 			resizeMethod: BitmapResizeMethod,
 			isAllowSwapSide: Boolean = false,
 			shouldUpscale: Boolean = true,
+			shouldFixOrientation: Boolean = false,
 		): Bitmap {
 			val opt = loadImageBounds(context, uri)
 			val shouldSwapSide = isAllowSwapSide &&
@@ -116,9 +119,13 @@ interface BitmapUtil {
 				logD(TAG, "Bitmap subsampled: ${bitmap.width}x${bitmap.height}")
 			}
 			if (bitmap.width < dstW && bitmap.height < dstH && !shouldUpscale) {
-				return bitmap
+				return if (shouldFixOrientation) {
+					fixOrientation(context, uri, bitmap)
+				} else {
+					bitmap
+				}
 			}
-			return when (resizeMethod) {
+			val result = when (resizeMethod) {
 				BitmapResizeMethod.FIT -> Bitmap.createScaledBitmap(
 					bitmap,
 					minOf(dstW, (dstH * bitmap.aspectRatio()).toInt()),
@@ -133,6 +140,62 @@ interface BitmapUtil {
 					true
 				)
 			}
+			return if (shouldFixOrientation) {
+				fixOrientation(context, uri, result)
+			} else {
+				result
+			}
+		}
+
+		/**
+		 * Rotate the image to its visible orientation
+		 */
+		private fun fixOrientation(
+			context: Context, uri: Uri, bitmap: Bitmap
+		): Bitmap {
+			return try {
+				openUriInputStream(context, uri)!!.use {
+					val iExif = ExifInterface(it)
+					val orientation =
+						iExif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1)
+					logI(
+						TAG,
+						"[fixOrientation] Input file orientation: $orientation"
+					)
+					val rotate = when (orientation) {
+						ExifInterface.ORIENTATION_ROTATE_90,
+						ExifInterface.ORIENTATION_TRANSPOSE -> 90f
+
+						ExifInterface.ORIENTATION_ROTATE_180,
+						ExifInterface.ORIENTATION_FLIP_VERTICAL -> 180f
+
+						ExifInterface.ORIENTATION_ROTATE_270,
+						ExifInterface.ORIENTATION_TRANSVERSE -> 270f
+
+						ExifInterface.ORIENTATION_FLIP_HORIZONTAL -> 0f
+						else -> return bitmap
+					}
+					val mat = Matrix()
+					mat.postRotate(rotate)
+					if (orientation == ExifInterface.ORIENTATION_FLIP_HORIZONTAL ||
+						orientation == ExifInterface.ORIENTATION_TRANSVERSE ||
+						orientation == ExifInterface.ORIENTATION_FLIP_VERTICAL ||
+						orientation == ExifInterface.ORIENTATION_TRANSPOSE
+					) {
+						mat.postScale(-1f, 1f)
+					}
+					Bitmap.createBitmap(
+						bitmap, 0, 0, bitmap.width, bitmap.height, mat, true
+					)
+				}
+			} catch (e: Throwable) {
+				logE(
+					TAG,
+					"[fixOrientation] Failed fixing, assume normal orientation",
+					e
+				)
+				bitmap
+			}
 		}
 
 		private fun openUriInputStream(

plugin/android/src/main/kotlin/com/nkming/nc_photos/plugin/ImageLoaderChannelHandler.kt

@@ -24,6 +24,7 @@ class ImageLoaderChannelHandler(context: Context) :
 						call.argument("resizeMethod")!!,
 						call.argument("isAllowSwapSide")!!,
 						call.argument("shouldUpscale")!!,
+						call.argument("shouldFixOrientation")!!,
 						result
 					)
 				} catch (e: Throwable) {
@@ -44,17 +45,18 @@ class ImageLoaderChannelHandler(context: Context) :
 	 * @param resizeMethod
 	 * @param isAllowSwapSide
 	 * @param shouldUpscale
+	 * @param shouldFixOrientation
 	 * @param result
 	 */
 	private fun loadUri(
 		fileUri: String, maxWidth: Int, maxHeight: Int, resizeMethod: Int,
 		isAllowSwapSide: Boolean, shouldUpscale: Boolean,
-		result: MethodChannel.Result
+		shouldFixOrientation: Boolean, result: MethodChannel.Result
 	) {
 		val image = BitmapUtil.loadImage(
 			context, Uri.parse(fileUri), maxWidth, maxHeight,
 			BitmapResizeMethod.values()[resizeMethod], isAllowSwapSide,
-			shouldUpscale
+			shouldUpscale, shouldFixOrientation
 		).use {
 			Rgba8Image(TfLiteHelper.bitmapToRgba8Array(it), it.width, it.height)
 		}

plugin/android/src/main/kotlin/com/nkming/nc_photos/plugin/ImageProcessorService.kt

@@ -518,7 +518,9 @@ private open class ImageProcessorCommandTask(context: Context) :
 			ExifInterface.TAG_IMAGE_DESCRIPTION,
 			ExifInterface.TAG_MAKE,
 			ExifInterface.TAG_MODEL,
-			ExifInterface.TAG_ORIENTATION,
+			// while processing, we'll correct the orientation, if we copy the
+			// value to the resulting image, the orientation will be wrong
+//			ExifInterface.TAG_ORIENTATION,
 			ExifInterface.TAG_X_RESOLUTION,
 			ExifInterface.TAG_Y_RESOLUTION,
 			ExifInterface.TAG_DATETIME,

plugin/android/src/main/kotlin/com/nkming/nc_photos/plugin/image_processor/ArbitraryStyleTransfer.kt

@@ -22,7 +22,8 @@ class ArbitraryStyleTransfer(
 		val height: Int
 		val rgb8Image = BitmapUtil.loadImage(
 			context, imageUri, maxWidth, maxHeight, BitmapResizeMethod.FIT,
-			isAllowSwapSide = true, shouldUpscale = false
+			isAllowSwapSide = true, shouldUpscale = false,
+			shouldFixOrientation = true
 		).use {
 			width = it.width
 			height = it.height

plugin/android/src/main/kotlin/com/nkming/nc_photos/plugin/image_processor/DeepLab3.kt

@@ -23,7 +23,8 @@ class DeepLab3Portrait(
 		val height: Int
 		val rgb8Image = BitmapUtil.loadImage(
 			context, imageUri, maxWidth, maxHeight, BitmapResizeMethod.FIT,
-			isAllowSwapSide = true, shouldUpscale = false
+			isAllowSwapSide = true, shouldUpscale = false,
+			shouldFixOrientation = true
 		).use {
 			width = it.width
 			height = it.height
@@ -54,7 +55,8 @@ class DeepLab3ColorPop(
 		val height: Int
 		val rgb8Image = BitmapUtil.loadImage(
 			context, imageUri, maxWidth, maxHeight, BitmapResizeMethod.FIT,
-			isAllowSwapSide = true, shouldUpscale = false
+			isAllowSwapSide = true, shouldUpscale = false,
+			shouldFixOrientation = true
 		).use {
 			width = it.width
 			height = it.height

plugin/android/src/main/kotlin/com/nkming/nc_photos/plugin/image_processor/Esrgan.kt

@@ -15,7 +15,7 @@ class Esrgan(context: Context, maxWidth: Int, maxHeight: Int) {
 		val rgb8Image = BitmapUtil.loadImage(
 			context, imageUri, maxWidth / 4, maxHeight / 4,
 			BitmapResizeMethod.FIT, isAllowSwapSide = true,
-			shouldUpscale = false
+			shouldUpscale = false, shouldFixOrientation = true
 		).use {
 			width = it.width
 			height = it.height

plugin/android/src/main/kotlin/com/nkming/nc_photos/plugin/image_processor/ImageFilterProcessor.kt

@@ -18,7 +18,8 @@ class ImageFilterProcessor(
 	fun apply(imageUri: Uri): Bitmap {
 		var img = BitmapUtil.loadImage(
 			context, imageUri, maxWidth, maxHeight, BitmapResizeMethod.FIT,
-			isAllowSwapSide = true, shouldUpscale = false
+			isAllowSwapSide = true, shouldUpscale = false,
+			shouldFixOrientation = true
 		).use {
 			Rgba8Image(TfLiteHelper.bitmapToRgba8Array(it), it.width, it.height)
 		}

plugin/android/src/main/kotlin/com/nkming/nc_photos/plugin/image_processor/ZeroDce.kt

@@ -14,7 +14,8 @@ class ZeroDce(context: Context, maxWidth: Int, maxHeight: Int, iteration: Int) {
 		val height: Int
 		val rgb8Image = BitmapUtil.loadImage(
 			context, imageUri, maxWidth, maxHeight, BitmapResizeMethod.FIT,
-			isAllowSwapSide = true, shouldUpscale = false
+			isAllowSwapSide = true, shouldUpscale = false,
+			shouldFixOrientation = true
 		).use {
 			width = it.width
 			height = it.height

plugin/lib/src/image_loader.dart

@@ -17,6 +17,7 @@ class ImageLoader {
     ImageLoaderResizeMethod resizeMethod, {
     bool isAllowSwapSide = false,
     bool shouldUpscale = false,
+    bool shouldFixOrientation = false,
   }) async {
     final result =
         await _methodChannel.invokeMethod<Map>("loadUri", <String, dynamic>{
@@ -26,6 +27,7 @@ class ImageLoader {
       "resizeMethod": resizeMethod.index,
       "isAllowSwapSide": isAllowSwapSide,
       "shouldUpscale": shouldUpscale,
+      "shouldFixOrientation": shouldFixOrientation,
     });
     return Rgba8Image.fromJson(result!.cast<String, dynamic>());
   }