feat: Add rotation to iOS (#548)

flutter-ml · Apr 15, 2024 · 315a7d6 · 315a7d6
1 parent 2d3b4f8
commit 315a7d6
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Showing 3 changed files with 61 additions and 3 deletions.
diff --git a/packages/example/lib/vision_detector_views/camera_view.dart b/packages/example/lib/vision_detector_views/camera_view.dart
@@ -378,6 +378,9 @@ class _CameraViewState extends State<CameraView> {
         rotation: rotation, // used only in Android
         format: format, // used only in iOS
         bytesPerRow: plane.bytesPerRow, // used only in iOS
+        cameraLensDirection: InputImageCameraLensDirectionValue.fromRawValue(
+                camera.lensDirection.index) ??
+            InputImageCameraLensDirection.front,
       ),
     );
   }

diff --git a/packages/google_mlkit_commons/ios/Classes/MLKVisionImage+FlutterPlugin.m b/packages/google_mlkit_commons/ios/Classes/MLKVisionImage+FlutterPlugin.m
@@ -32,12 +32,17 @@ + (MLKVisionImage *)bytesToVisionImage:(NSDictionary *)imageData {
     NSNumber *height = metadata[@"height"];
     NSNumber *rawFormat = metadata[@"image_format"];
     NSNumber *bytesPerRow = metadata[@"bytes_per_row"];
+    int rotation = [metadata[@"rotation"] intValue];
+    int cameraLensDirection = [metadata[@"camera_lens_direction"] intValue];
+    UIImageOrientation imageOrientation = [self imageOrientationFromRotation:rotation cameraLensDirection:cameraLensDirection];
     CVPixelBufferRef pxBuffer = [self bytesToPixelBuffer:width.unsignedLongValue
                                                   height:height.unsignedLongValue
                                                   format:FOUR_CHAR_CODE(rawFormat.unsignedIntValue)
                                              baseAddress:(void *)imageBytes.bytes
                                              bytesPerRow:bytesPerRow.unsignedLongValue];
-    return [self pixelBufferToVisionImage:pxBuffer];
+    MLKVisionImage *image = [self pixelBufferToVisionImage:pxBuffer];
+    image.orientation = imageOrientation;
+    return image;
 }
 
 + (CVPixelBufferRef)bytesToPixelBuffer:(size_t)width
@@ -66,4 +71,21 @@ + (MLKVisionImage *)pixelBufferToVisionImage:(CVPixelBufferRef)pixelBufferRef {
     return [[MLKVisionImage alloc] initWithImage:uiImage];
 }
 
++ (UIImageOrientation)imageOrientationFromRotation:(int)rotation cameraLensDirection:(int)cameraLensDirection {
+    switch (rotation) {
+        case 90:
+            return cameraLensDirection == 0 ? UIImageOrientationRight  // Rotates the image 270 degrees to the left
+                                            : UIImageOrientationRightMirrored;  // Rotates the image 270 degrees to the left (image is mirrored)
+        case 180:
+            return cameraLensDirection == 0 ? UIImageOrientationDown  // Rotates the image 180 degrees to the left
+                                            : UIImageOrientationDownMirrored;  // Rotates the image 180 degrees to the left (image is mirrored)
+        case 270:
+            return cameraLensDirection == 0 ? UIImageOrientationLeft  // Rotates the image 90 degrees to the left
+                                            : UIImageOrientationLeftMirrored;  // Rotates the image 90 degrees to the left (image is mirrored)
+        default:
+            return cameraLensDirection == 0 ? UIImageOrientationUp // Rotates 0 degreees
+                                            : UIImageOrientationUpMirrored;  // Rotates the image 0 degrees (image is mirrored)
+    }
+}
+
 @end
diff --git a/packages/google_mlkit_commons/lib/src/input_image.dart b/packages/google_mlkit_commons/lib/src/input_image.dart
@@ -56,10 +56,13 @@ class InputImageMetadata {
   final Size size;
 
   /// Image rotation degree.
-  ///
-  /// Not used on iOS.
   final InputImageRotation rotation;
 
+  // Camera lens direction.
+  ///
+  /// Not used on Android.
+  final InputImageCameraLensDirection cameraLensDirection;
+
   /// Format of the input image.
   ///
   /// Not used on Android.
@@ -76,6 +79,7 @@ class InputImageMetadata {
     required this.rotation,
     required this.format,
     required this.bytesPerRow,
+    required this.cameraLensDirection,
   });
 
   /// Returns a json representation of an instance of [InputImageMetadata].
@@ -85,6 +89,7 @@ class InputImageMetadata {
         'rotation': rotation.rawValue,
         'image_format': format.rawValue,
         'bytes_per_row': bytesPerRow,
+        'camera_lens_direction': cameraLensDirection.rawValue,
       };
 }
 
@@ -155,3 +160,31 @@ extension InputImageFormatValue on InputImageFormat {
     }
   }
 }
+
+/// The camera lens direction to be specified
+///
+/// Not used on Android.
+enum InputImageCameraLensDirection {
+  front,
+  back,
+}
+
+extension InputImageCameraLensDirectionValue on InputImageCameraLensDirection {
+  int get rawValue {
+    switch (this) {
+      case InputImageCameraLensDirection.back:
+        return 0;
+      case InputImageCameraLensDirection.front:
+        return 1;
+    }
+  }
+
+  static InputImageCameraLensDirection? fromRawValue(int rawValue) {
+    try {
+      return InputImageCameraLensDirection.values
+          .firstWhere((element) => element.rawValue == rawValue);
+    } catch (_) {
+      return null;
+    }
+  }
+}