fix: types and revert bg, fg in selfie segmentation

Author: chmjkb

packages/react-native-executorch/common/rnexecutorch/models/image_segmentation/BaseImageSegmentation.cpp

@@ -105,8 +105,8 @@ std::shared_ptr<jsi::Object> BaseImageSegmentation::postprocess(
     for (std::size_t pixel = 0; pixel < outputPixels; ++pixel) {
       bgPtr[pixel] = 1.0f - fgPtr[pixel];
     }
-    resultClasses.push_back(bg);
     resultClasses.push_back(fg);
+    resultClasses.push_back(bg);
   } else {
     // Multi-class segmentation (e.g. DeepLab, RF-DETR)
     for (std::size_t cl = 0; cl < numChannels; ++cl) {
@@ -121,9 +121,9 @@ std::shared_ptr<jsi::Object> BaseImageSegmentation::postprocess(
   auto *argmaxPtr = reinterpret_cast<int32_t *>(argmax->data());
 
   if (numChannels == 1) {
-    auto *fgPtr = reinterpret_cast<float *>(resultClasses[1]->data());
+    auto *fgPtr = reinterpret_cast<float *>(resultClasses[0]->data());
     for (std::size_t pixel = 0; pixel < outputPixels; ++pixel) {
-      argmaxPtr[pixel] = (fgPtr[pixel] > 0.5f) ? 1 : 0;
+      argmaxPtr[pixel] = (fgPtr[pixel] > 0.5f) ? 0 : 1;
     }
   } else {
     std::vector<float> maxLogits(outputPixels,

packages/react-native-executorch/src/modules/computer_vision/ImageSegmentationModule.ts

@@ -12,10 +12,7 @@ import { RnExecutorchErrorCode } from '../../errors/ErrorCodes';
 import { RnExecutorchError } from '../../errors/errorUtils';
 import { BaseModule } from '../BaseModule';
 
-const ModelConfigs: Record<
-  SegmentationModelName,
-  SegmentationConfig<LabelEnum>
-> = {
+const ModelConfigs = {
   'deeplab-v3': {
     labelMap: DeeplabLabel,
     preprocessorConfig: undefined,
@@ -24,7 +21,10 @@ const ModelConfigs: Record<
     labelMap: SelfieSegmentationLabel,
     preprocessorConfig: undefined,
   },
-} as const;
+} as const satisfies Record<
+  SegmentationModelName,
+  SegmentationConfig<LabelEnum>
+>;
 
 /** @internal */
 type ModelConfigsType = typeof ModelConfigs;
@@ -96,7 +96,10 @@ export class ImageSegmentationModule<
     onDownloadProgress: (progress: number) => void = () => {}
   ): Promise<ImageSegmentationModule<ModelNameOf<C>>> {
     const { modelName, modelSource } = config;
-    const { labelMap, preprocessorConfig } = ModelConfigs[modelName];
+    const { labelMap } = ModelConfigs[modelName];
+    const { preprocessorConfig } = ModelConfigs[
+      modelName
+    ] as SegmentationConfig<LabelEnum>;
     const normMean = preprocessorConfig?.normMean ?? [];
     const normStd = preprocessorConfig?.normStd ?? [];
     const paths = await ResourceFetcher.fetch(onDownloadProgress, modelSource);